NOTE: The below was originally to Paul but others may find it interesting, of use, etc. If I misquoted anybody's notes from the archives please let me know and I'll try to correct quickly. Just remember life is hectic. :) If you are quoted here and want your name removed, let me know and we'll make it impersonal. Thanks everyone for such a great discussion list. I learned a lot going through the archives and making these notes. Perhaps someday someone can make a real FAQ for the list! -Walter Standard Disclaimer: These notes are NOT comprehensive in any way shape or form. They are merely notes I made for myself to help me study the topic. If you follow any of the advice in here and get hurt, destroy a planet, cause an intergalactic war, etc then it is your own fault. You use any info contained here-in at your own risk! There is no warrantee or guarantee! From: Walter H. Jeffries Date: June 23, 2004 8:38:12 PM EDT To: Paul Sarnstrom Subject: FC Notes Hi Paul, Here are the promised notes on my reading through the FC archives plus other sources. The "black book" I referred to in another message is "The Visual Handbook of Building And Remodeling" by Charlie Wing published in 1990 by Rodale Press. It is an excellent reference for construction in general. All of this is copyleft or right what ever. Most of it is my own words but noted, annoted and referenced of other people's writings. Sometimes I added parentheticals to other people's comments with my initials (wvj). Lot's of URLs. You have permission to use anything of mine that appears in the notes below in any way you like. If you make a million, cazillion dollars maybe you can pay off my mortgage. :) I of course would not mind a mention. URL pointer to me and my stuff, etc. Cheers, -Walter in West Topsham, Vermont --- Laser Printer Iron-on Heat Transfer Toner: http://transfertoner.com/ Custom Transfers on Shirts, mugs & more: http://bltserve.com/ Holly's Pencil Portraits: http://hollygraphicart.com/ For Sale: 1825 post & beam farm house, 4 square cape with kitchen el, pit sawn boards, big beams, beehive oven, 2 fireplaces, helical chimney, own a piece of Vermont history - one of the first houses in the area. Must be moved! Foundation stones also available. FC Notes: Mixes Paul: http://ferrocement.net/archives/msg13809.html Be sure to get mason's sand and not concrete sand. Latter too coarse for fc. Masons sand $5-$7/cuyd at rm plants Don't put through screen door as it will yield too many fines. RichardMcCabe disagrees: http://ferrocement.net/archives/msg13850.html Suggests natural mix of sizes better for most projects. Refs Martin Iorns FC Houseboat book. "Fly ash processed for use in concrete can be substituted 1/3 to 1/2 the cement volume. Silica fume (optional) ...is used for ultra-high strength applications. Plaster sand passing a 15-mesh sieve." Range of aggregate sizes -> better mix Size should not be larger than lath openings though. Divine mix? I would put forward 2:1, sand and cement powder, by volume. The ratio is .35 -.4 parts water to 1 part cement. Basically the cement and water become a fluid that fills the interstices between the particles of sand. If the sand is wet when you prepare your mortar this will of course affect your final water-cement ratio. Corrections to book by Stanley Albercrombie 'Ferrocement" p.59: by volume 1 parts water 2 parts cement 4 parts sand p. 148: should have the feel of thick bread dough before rising FlyingConcrete's Fav Mix: 3 perlite, 1 sand, 1 cement, 1/2 lime +fiber for first coats http://www.ferrocement.net/archives/msg12485.html http://www.ferrocement.net/archives/msg02087.html Addition of fly ash will improve flowability of concrete or mortar. Usually, it is one of the components of Self-Compacting Concrete. To avoid strength loss use only 15% by weight as cement replacement. For instance: cement 0.85 kg fly ash 0.15 kg sand 2 (and up to 4) kg water 0.45-0.55 kg It will provide you with mortar similar to standard ASTM C109 test. To improve performance you could use 0.3-05% of superplasticizer SP admixture (and up to 0.8% of dry SP as weight of cement/binder) and reduce water ~20%. Overdosage of SP might reduce your strength in case of naftalin based SP (like Daracem200). If you can not provide precise control of SP dosage at site, better use melamine based SP (like Melment), which is more expensive, but has no adverse effect in case of overdosage. The best result you could achieve in case of silica fume addition into this mix. Use 5% (and up to15%) of silica fume by weight as cement replacement. Increasing of silica fume content will require more SP (and after optimal level will have no positive effect on strength). Use the following design for high performance mortar: cement 0.75 kg fly ash 0.15 kg silica fume 0.10 kg SP (Daracem200 from GRACE or Melment) 0.01 kg dry (or up to 0.03 kg in case of liquid) sand 2 (and up to 4) kg water 0.2-0.35 kg You will be surprised with flowability and strength of this mortar! I hope it will be useful. Konstantin Paul: http://www.ferrocement.net/archives/msg08886.html In the simplest explanation ferrocement is composed of layers of wire mesh for reinforcement and mortar composed of Portland cement and sand. The general ratios for the mortar are 1 part cement and 2 parts sand to 1 part cement and 3 parts sand. For a water proof structure the ratio of water to cement is .4 [or less] parts water to 1 part cement. All proportionsare weight. [Interesting as he previously said it was by volume.] How about good old hydrated lime. Thats what I always use to make things sticky. No more than 10% lime to cement powder. Also fire clay works. And it's great for pumping too. An oldtimer once told me about it. He said "Makes the mud slicker than owl shit." Lime and some synthetic fibers will go a long way towards making things stick. Incidentally, I've found steel fibers to also allow for a much better spray pattern. They somehow homogenize the mud as it's packing up and you end up with far less lumps and uneven areas. Peter. Min/Max Slumps: http://www.union.edu/PUBLIC/CERDEPT/FACULTY/GHALY/CONCRETE/WtUSAir.htm 1-2-3: cement-sand-gravel: http://www.angelfire.com/in2/manythings/page5.html "Throwing in a shovel full of construction lime for each sack of cement -> harder since lime and cement react with CO2 in air to form aragonite. Good for plastering jobs. Not useful for foundation work." Monolith Domes Shotcrete: http://www.monolithicdome.com/construction/mix/ Cement2bags(188lb):Water10gal(80lb):Sand2-FiveGalBuckets(690lb):PeaRock2-FiveGalBuckets(140lb):Kel-Crete2.5oz(add in water)($65/gal):KapejoFibers(1/3lb)(add fibers last)($3/0.75lb) KapejoFibers are a single strand fiber with minimal climbing and alki resistance for shotcrete. 1lb=millions of fibers. Konstantin: http://www.ferrocement.net/archives/msg06354.html Excel & HTML charts: http://www.ferrocement.net/archives/msg06376.html business.vsnl.com/mgadre/default.htm Andrew Bingham: http://www.ferrocement.net/archives/msg06335.html Forms = ready mix plant = 3.5/1 sand/cement = six sack concrete (6 sacks per cubic yard) Shotcrete = 2/1 = nine sack Ferro = 3/1 = 6.75 sack ratios can vary widely. Important to minimize water addition for strength and then keep damp for 28 days to maximize cure strength. Additives like Kel-Crete help with workability and retaining water for curing. CKunzeA: http://www.ferrocement.net/archives/msg05926.html Mix is sand 5 to cement 3 to liquid about 2, liquid was water 9/10 and acrylic 1/10, mixed wet consistency Chart of mixes and strengths: http://www.stableair.com/Page4.htm Low and beneficial water cement ratios, average w/c=0.30 http://www.ferrocement.net/archives/msg04111.html http://www.kuraray-am.com/pvaf/mix_designs.php Mix Proportions Water OPC S FA HPMC SP VF FA-48 380 678 484 291 1.91 6.46 26 Dosage of Fiber is 2.0vol% of composite. (1.4% by weight) / Units (kg/m3) FA-48 640 1143 816 490 3.2 10.9 44 Units (lbs/yd3) U OPC: ordinary Portland cement (specific gravity = 3.16), U S: silica sand (specific gravity = 2.62, mean diameter=0.2mm; 70 or 80 screen) U FA: fly ash (specific gravity = 2.00) U HPMC: hydroxypropylmethylcellulose, SP: superplasticizer: polycarboxyl-polyether compound U VF: Fiber: REC15x12mm (specific gravity = 1.3) Notice: Mixing conditions, procedures and materials will affect workability and fiber dispersion. Test your conditions. Mixing procedure Hobart mixer (Other mixers may require additional fiber mix time.) OPC.S,FA_1min_Water_1min_HPMC_2min_SP_3min_VF_3min_Pour Chris: a typical mix for me is 2 coffee cans portland, 3 coffee cans sand, one coffe can of water with polymer in it (usually 1/4 polymer, 1/2 for bonding if necessary), and about a 8 ounce cup of pva fiber i mix the sand and one can portland, then add all liquids, mix, then add fibers, mix, this is very wet and the fibers mix easily, add last can of portland and finish mixing http://www.ferrocement.net/archives/msg05443.html I had heard adding a little Joy liquid soap into the mortar mix would replace some water and make the mix smoother. Today I tried it. The only thing I had handy was Ivory ultra concentrated dish washing liquid. OH MY! a little goes a very long way. I added 2 good squirts to a dry mix that would have been perfect for the hopper sprayers. Right in front of my eyes the mix got wetter without adding more water. The mix also grew from the air in the mix. I just went out to see how it is firming up. It is like firm frosting. This was a quick and loose experiment with little attention to details and measuring. I did see that I needed to start with a much dryer mix next time and use a bit less soap. This mix would work great for pouring in thin forms. Very self leveling. Joy is poor man's Kalcrete. Nolan Herbert Crow did same with Ivory liquid soap and Tide powder soap 1tsp/gal and liked them but noted weaker and harder to know when concrete is set. Suggests don't use if using latex or polymer ameder. Suggested even less soap would be better and that it would help with spray gun work: http://www.ferrocement.net/archives/msg05447.html I did a similar thing in Texas, but after experimenting with several different additives i settled on the acrylic polymer for its strength enhancing abilities. Try a cylinder of your mix and see what changes it makes besides reducing the surface tension of the water. Haven't tried Kalcrete that I remember. The difference between the end product of soap which makes the water slippery, and Acrylic polymer which lengthens the molecular bond of the cement in the matrix, is that the polymer leaves a stronger concrete. Stronger concrete can be acheived by reducing the water, as you know, but not as much as adding the polymer makes it for the same workability. What is the basic chemical composition of the Kalcrete? Loren High Performance Concrete: http://www.silicafume.org/slideshow.cgi?p=43&c=2&l=73 Ted on EEC: http://ferrocement.net/archives/msg14590.html There must be a strong 'chain of command' staggered agr size for cement to grab onto. Perline is bad Sharp edges and rough particles are good Many dif particle sizes are good - think fractal matrix. For the ultimate try diamonds or carborundum :) PVA and fiberglass strands overlap and grip. Light concrete and EEC seem to be opposites (wvj) Benefits of Silica Fume in Shotcrete: - Reduction of rebound loss up to 50% - Increased one-pass thickness up to 12 in. (300 mm) - Higher bond strength - Improved cohesion to resist washout in tidal rehabilitation of piles and seawalls NYSDOT class HP concrete: - PC ............... 500 lb/CY ...... 300 kg/m3 - Flyash ........... 135 lb/CY ...... 80 kg/m3 - Silica fume ...... 40 lb/CY ...... 25 kg/m3 - Water Content..... 0.40 Lightweight Concrete: http://ferrocement.net/archives/msg11881.html mxSteve: pumace or scoria to concrete at 8/1 ferro, 10/1 blocks RichardAustin: perline/cement 6/1 or 8/1 no sand, 20pcf, 100psi compressive strength source is: http://www.schundler.com/const.htm Actual mix designs: http://www.schundler.com/perlcon.htm Various Concrete Mix Densities and strengths: Density Strength Vermiculite 15-40 300-1000 Perlite ~17-50 ~400-1000 Pumice 50-80 1000-~1800 Scoria 60-90 ~1200-~3000 Cinders 75-120 ~1700-6000 Exp. Shale/Clay/Slate 85-115 2500-~5000 Rotary Kiln Exp. Shale/Clay/Slate 90-120 ~3000-6000 Sintered Expanded Slag 90-120 ~3000-6000 Density in pounds per cubic foot (pcf) Strength in pounds per square inch (psi) Source: MxSteve's diagram which he got somewhere else I think... I forgot to anote this. Article on Concrete Mixes: http://ferrocement.net/archives/msg12807.html Odd mix: http://ferrocement.net/archives/msg13763.html Soil in Mix: http://ferrocement.net/archives/msg13647.html RexTarr cautions against using soil for structural elements like walls, ceiling, roof. Okay for floor. My note: varies with your soil. We have some that is pure sand. Others clay. Others gravel. etc. Paul & dlJohnson: http://ferrocement.net/archives/msg13815.html My existing soil is very low in organic matter and is mostly silt, sand and clay. I used a small concrete mixer and dry mixed 9 shovels of soil with 1 shovel ofcement so the mix is roughly 9 parts soil to 1 part cement. After the cement was thoroughly incorporated I shoveled the dry mix into the bags, laid them out and flattened them somewhat to provide a level base for the first course of bales. After the foundation was done I soaked the bags with a hose several times the first day and a couple of time the next day. Mix in by rotortilling. Like we make our driveway but using york rake. RichardMcCabe: clay good, organics bad - http://ferrocement.net/archives/msg14279.html High Performance Cements good for Ferro Concrete: http://www.geocities.com/ResearchTriangle/Forum/1657/Cement/high_performance_cement.html Surface Bonding home-mixed http://www.ferrocement.net/archives/msg05550.html Laminated Ferro Cement http://www.ferrocement.net/archives/msg05449.html http://www.ferrocement.net/archives/msg05484.html Laminated method of ferro cement developed in 1964 by Martin Iorns (on list): permits the placing of any type and amount of reinforcing, from flyscreen to closely-spaced rebar, and makes high-impact ferrocement boat hulls possible. A dome with compound curvatures is just like a boat hull turned upside-down, but needs much less reinforcing. The form can be any continuous surface, but the first layer placed on an inflatable form will probably need to be light-weight acoustical plaster or paper-pulp in a bonding agent. A layer of mortar about 3mm thick (with a water/cement ratio below .4) is brushed or sprayed on the surface of the form, and a strip of mesh is gently pressed in while the mortar is still soft. Successive layers of mortar and mesh are then added until the structure has reached the desired thickness and strength. This embedding concept ensures there are no voids. The most cost-effective mesh for boat hulls is expanded metal plaster lath, but chicken wire is okay for terrestrial structures. A spray rig replaces a hod-carrier and speeds up the process Regarding curing: add each new layer of lath while the mortar is still soft enough to embed the lath or other mesh. Before you break for several hours or days, brush back the mortar until the bare mesh is exposed. When you are ready to start again, brush or spray on a new layer of mortar and embed mesh as before. In critical applications, such as boat hulls, we use we start anew with a slurry of neat cement or a coat of acrylic latex with 10%-15% solids (Acryl 60, Larson 101, and most house brands contain about 25% solids, so can be diluted with an equal amount of water). In using acrylic latex as a bonding compound, be sure you add the new mortar before the latex dries out and becomes shiny, otherwise it might act as a release agent instead of a bonding agent! We bought formula E-330 (now MC76) from Rohm & Haas, in drums, containing 47% solids, and diluted it with water to 25% solids. I assume that Acryl 60, Larsen 101, and various house brands, are doing much the same thing, but probably adding de-foaming agents which were not needed for our purposes. The current price from Home Depot is about the same as a good grade of latex paint. There may also be some latex paints that could serve the same purpose, but the ones I tried had incompatible additives. I don't know what the additives are and haven't seen a need to ask, since I always use an acrylic latex that sells for about the same price as a latex paint. Don't confuse "acrylic" latex with "vinyl" latex. The acrylic is highly UV resistant, and once dry is waterproof. Do not allow it to freeze. Hobby latex is probably too expensive to consider. Old latex may or may not be compatible--just test its reaction in a neat cement paste. It is not a problem to make concrete impermeable. The universal mix with silica fume or metakaolin will provide concrete which is impermeable to water. You could use it with fibers. Waterproofing Aqua-Lock made from crushed Novaculite (whetstone) in Malvern, AR 5:1 black acrylic latex paint + 1 cup of Acryl 60 and water to a thin paint consistancy and then paint on the wall (outer on ug house). http://www.ferrocement.net/archives/msg05535.html http://www.aquron.com/products.htm http://www.aquron.com/products/aqucpt2000.htm Loren finds it great. http://www.ferrocement.net/archives/msg05624.html Owens Waterproofing Products, Inc. P.O. Box 523 Hot Springs AR 71902 501.623.2320 http://www.ferrocement.net/archives/msg05525.html expensive water proofer to the mix that added about $30 per yard to the cost of the mud. it was called Krystal International Membrane from Kryton. They told me that they would actually trust it for a water proof roof with no other roofing. If a crack ever develops,it will use the water to grow crystals and plug the hole. http://www.ferrocement.net/archives/msg05725.html Xypex, Krystal ... I always use Tegraproof. They are very expensive, but near miraculous in their performance. Unlike regular cement, they grow very long crystals, they seal microcracks by capilarry action and most amazing of all, if a crack develops in the future they reactivate and start cyrstallizing again. If need be they could be resurfaced with another cement type coating with only a good scrubbing. They are NSF approved for drinking water too. Peter Keith Britton: http://www.ferrocement.net/archives/msg03434.html use an admix and a silicate paint or surface hardener where flexure is absent. I had forgotten about calcium stearate until JJ Arnold mentioned it, and I'm now looking hard at it as a possibility where flexure is significant. (Thanks JJ.) Stearine is used as a multipart mold release in ceramics, applied dissolved in an organic solvent. You have to be extremely careful not to get any on the absorbent plaster of Paris surfaces, because they will never pass water again. I'm trying to find out something about Berylex admix, because it reportedly protects steel with "chromium" and so might passivate zinc. Steve Miller: liked Quikcrete Cure-n-Seal: http://www.ferrocement.net/archives/msg06285.html Nolan: When I put a stain on DRY concrete, it actually suctions into the concrete about a quarter inch. Loren: 8cement 27 sand, water to consistency desired and Acrylic polymer to the desired workability, usually about a cup to a bag of cement. Then I throw in a small handful of poly fibers since I have so many bags of them. Nolan: Kim Krystol or Zypex: http://www.ferrocement.net/archives/msg06280.html Jean Wheel did not like Aliphatic urathane floor sealer - too soft, possibly not applied right she said: http://www.ferrocement.net/archives/msg07694.html Steve liked waxing (ivos brand Floor wax) and said Trewax should be similar (livos is carnauba, beeswax, citrus, etc). He has also used homemade mix of beeswax, turpentine, linseed heated which came from woodworking - use good ventilation when preparing and applying! Also danger of fire when heating or storing as rags or spilled.: http://www.ferrocement.net/archives/msg07695.html Jean Wheeler mentions beeswax heated with turpentine to protect metal Vapor Barriers: http://ferrocement.net/archives/msg11617.html 1. Use natural ventilation AMAP (As Much As Possible). Prefereably non-powered passive. 2. Vapor barrior goes on the warmer, moister side of the wall. Other side must breath. 3. Keep moist air away from cold surfaces so it won't condense. Someone had mentioned that plaster of paris is a barrier to vapors and water. Perhaps a high plaster of paris plaster mix would be good on the inside. Caulking: Ted: http://ferrocement.net/archives/msg15770.html really like how industrial grade urethane caulking performs. It cures into a hard rubber and really sticks! Silicone, and silicone with acrylic/vinyl is good. Vinyl caulking is good, but...not for the ages. I just don't trust this with all the lineal area you are going to caulk, that you'll get a 100% barrier. Additives: Flyash: Martin says 30% to 35% http://www.ferrocement.net/archives/msg05751.html Makes concrete stronger but it takes longer to cure. Possible increase in cracking and radiation levels though. fly ash is sticky: www.boralmti.com acrylic and latex are sticky. Acryl 60 is my favorite. Cement is sticky, of course. Rich mixes are good. Very fine silica sand - like 90 or 100-- are good for a variety of reasons. And the winner in the stickiness contest is www.easyspred.com but you can also go to home depot and get masons clay or whatever. Bentonite swells, so be careful there. Keith Britton: http://www.ferrocement.net/archives/msg05756.html It doesn't take long to see why P.K.Mehta commands respect from the guys who grub mud for a living, does it? I particularly liked his low key economic points - ~50% flyash eliminating need for superplasticizer while simultaneously eliminating need for permeability/corrosion admix at no (or actually reduced) binder cost... A subtlety which he didn't address may touch on field reports of reduced shrinkage cracking, of which Middlebrook's short paper at the same meeting is typical. http://www.buildinggreen.com/features/flyash/middlebrook.html Fly ash is the very fine mineral material that got hot enough to melt in a burner/furnace/boiler and was carried off in the flue gas. It's in the form of tiny spheres because that's the shape small liquid droplets take and the particles freeze back to solid the same way. They are commonly referred to a cenospheres, so that's as useful word for search engines. Latex Paint: http://ferrocement.net/archives/msg12003.html The quick answer is 10 to 20 percent solids, but there is more to it than that. Be careful not to confuse "amount of latex paint" with "amount of latex". Latex paint varies, but figure 25% solids by weight. Before considering latex, remember these caveats: 1. Do not use in enclosed structures like water tanks, (I don't know why, but I read that) 2. Remove forms as soon as possible; 3. Wet cure for only 3 days: after that you degrade the concrete 4. If you are in a continuously wet environment, wait the full cure period before getting it wet, or consider using only acrylic. I would not recommend using waste paint in mission-critical applications. There has been very little research on this, but one Canadian city had varied results. The problem is that there is stuff in paint--like solvents--that interfere with the hydration process. You want to get as much of that stuff out as possible, (more on that below). Acryl60 is the 'real-stuff' you want to use in mission critical applications. The normal ratio of Acryl 60 to clean potable water is 1 part Acryl 60 to 3 parts of water (1:3). Where increased physical and chemical resistance are required, increase the Acryl 60 content in the mixing liquid to a 1:2 or 1:1 Acryl 60 to water ratio. Always mechanically mix. Do not overmix or mix at a high speed. Acryl 60 is a common trade name by the Thoro group. If you sniff the additive it should smell like a dilute ammonia, only sweeter. The thicker it is, the richer and better value it is. If it smells like elmer's glue, it is. Not near as strong a finished product. I ran into an older friend today at Wal-Mart who said he had bought some Color Tile acrylic for 50cents a gallon at surplus in Chicago. It is 4 times the strength of the watered down Acryl 60. I'm going to stop by and get those off him!!! The Acryl 60 cost me $83 for a 5 gallon bucket the last time I bought some. Loren Aquagels manual: http://www.nalusda.gov/ttic/tektran/data/000008/36/0000083669.html Non-structural, air-entrainment, lightweight insulative wheat starch biopolmer composite. Roof tiles, floors, insulation in walls, roofs, around fireplaces. Coal ashes tend to settle things down well also. Ashes In fisheries ashes have been used to seal pond leaks by pouring the wood or coal ashes in the water at the suspected location of the leak without draining the pond. Evidently the ashes settle into the porous part of the pond bottom and tend to seal things off. This solution is not recomended for piping type of leak where you have a finger sized hole in the dike, just for slow seeps. So ashes may have some properties that would decrease the porousity of the FC. Rebar: http://www.ferrocement.net/archives/msg02805.html Reinforcing bars should be handled and stored in such a manner that they will not be bent out of the planned shape. They should not be stored directly on the ground. Open storage of reinforcing steel will in most cases result in rusting. The suitability of rusting reinforcing has been the subject of some concern in past years. Studies going back to 1920 have demonstrated that a rust film or tight mill scale, rather than harming the bond between steel and concrete, actually causes an improvement in the bonding characteristics of the steel. Andy Bingham 20040602: User 6x6 6guage not 10guage. Harder to shape but much more stable. Also 1/2" rebar is way stronger than 3/8" and his preference. Keith Britton: http://www.ferrocement.net/archives/msg03434.html Rust good Galv so-so Mesh watch for voids Wire always within cement by 3x wire diam Corrosion of rebar/metal in fc boats common - marine env hard on wire Reinforcing: 6x6-10-10 (#6666) gives much better results than lath, fiber or chicken wire in mxSteve's meteorite tests: http://www.ferrocement.net/archives/msg05994.html 2'x2'x2" slab 3/1 sand/cement vibrated tiles Unreinforced destroyed by 36kg steel dropped 1 meter - 8 chunks fiber 3/4" 20% more than recommended destroyed by same - 5 chunks ferro 3 layers 26 guage elath destroyed at 2 drops from 1.5 meters but holds together #6666 2 layers minimum failure after many drops from 2.5 meters Rebar must be 3" up in footings, tightly tied, ties are temp, metal must touch to prevent levers, inside by 3 diameters. Ted & Bo: http://ferrocement.net/archives/msg13582.html expanded lath creates shear planes not created by round wire WWM. WWM better in this. best is mix rebar, 66-10 WWM, fine WWM, hard sprayed on fiberous cement (several fiber sizes) RichardMcCabe: http://ferrocement.net/archives/msg13583.html Overly long fibers -> voids First coat w/o fibers(??? contradicts later info by email...???) Nolan: http://ferrocement.net/archives/msg08905.html Bending #4 is a b**ch compared to #3. Perhaps it is to late in the game but you might ask your engineer about the bar spacing if you choose to use #3 instead. My friend Norm did his first dome in #4 bar and then redid his calcs to use #3 from then on. [Thus use #4 for straights and #3 for bends. Someone else mentioned using a conduit bender. Or 3 pin bender. Or pipe. Or my fav, across my chest or my shoulder. :) -WVJ] Peter of HI ferrotank building fame uses 4 penny nails (100 lbs/cuyd of cement sometimes 250 lb/cuyd) (bright, not finished, larger nales or wire strands better if project can handle it) instead of steel fibers because they are cheaper for him in HI. Uses for free-form work, pools, ponds, not tanks.: http://www.ferrocement.net/archives/msg00492.html Richard tried nails and liked better than Dramix steel fibers because less finish work and didn't stickup through the floor surface. Dramix come glued together, nails don't. http://ferrocement.net/archives/msg08939.html Richard: http://www.ferrocement.net/archives/msg06012.html Nylon and Polypropylene have same modulus, stretchy, no good for tensile. 5% typical. (by weight, volume???) Poly fibers good for crack control. Steel better for reinforcing tensile strength but more expensive. Typically 0.25% to 5%. Others say 2% Dramix steel fibers are fantastic. 50 cents/pound: http://www.ferrocement.net/archives/msg12020.html Must coat with a surface layer to prevent rusting of exposed. 4D nails also good. Some like nails, others not. mxSteve: http://www.ferrocement.net/archives/msg12016.html Carbon ideal but very expensive. But brittle. $9/lb in 2002. Need 5%. Steel is excellent. Nylon stronger than Polyethelene: http://www.nycon.com and http://www.fibermesh.com/engineers/main.asp Kevlar excellent Zirconia-coated fiberglass a little brittle. Do NOT use regular fiberglass as it will deteriorate in alkaline environment. Must coat with Zirconia. Most plants use polyethelene fibers. Fibers are great but not a replacement for rebar. Good results with reinforcing fabric (AR - Alkali Resistant Glass): http://www.eifsfacts.com/ System mxSteve prefers: 2 FC skins 1/2 to 3/4" thick filled with 6-12" cellular concrete. http://www.nycon.com/ RichardMcCabe: http://ferrocement.net/archives/msg10009.html Dramix fibers 30 mm or so. 4 to 6% by weight. Mix well. I had some problems when I didn't mix long enough. (they come stuck together) If you are putting Dramix steel fibers into a conventional mix (7 bag? 9?) then drop the boxes off at the readimix yard and have them toss the boxes in: the boxes disintegrate. With the gravel in the mix, the Dramix fibers will get mixed in nicely. The problems I had was mixing with mortar--sand only--they tended to stay clumped together. Ron: Good fiber overview: http://www.fibersource.org/overview.htm Steve Miller: http://www.ferrocement.net/archives/msg06402.html I think the construction of concrete domes can be made safer and simpler by use of a geodesic armature, particularly as the domes increase in size. The gradual curves in non geodesic domes are more prone to starting cave ins. RichardMcCabe: http://ferrocement.net/archives/msg13846.html PVA mesh (not yet available) and Nylong mesh (esp free mesh) being good for mech req of holding mud while curing. Rebar Tieing/Welding/Attaching: Welding is stronger than tieing but dangerous if not done properly. Plastic/nylon ties used - fast & strong: http://www.ferrocement.net/archives/msg06200.html http://www.americanwiretie.com/tytools.htm Welded Wire Mesh has greater tensile strength than Expanded Lath but the latter some find easier to work with. WWM typically is 1/2" corrosion inhibited (galvanized?) Martin Iorns on this topic: http://ferrocement.net/archives/msg11051.html ExMetalLath is more cost effective and flat metal provides more bonding surface area. Layer & laminate. Use 2.5lb/sqyd or better 3.4 Freshly coated galv lath can cause gas bubbles to form on ungalv rods. Let sit in air. Or prevent with 200ppmillion Chromium Trioxide to mixing water. Buy 6 x 6-10 wire rebar seller and such. 100' x 60" or 72" widths. $65 a roll. Tying wire to rebar and wire: http://www.ferrocement.net/archives/msg04032.html Pneumatic Hog Ring Gun! I gave him $100 for it. Called around a bit, and found that Stanley-Bostich makes hogring staples-on-a-stick. A case of 10,000 sells for $28.50. (And the gun sells new for about $450.) Having experienced cramped hands after a day of squeezing clinching pliers, I think I'm gonna like this. Metals & Concrete: Ted Baumgart: http://ferrocement.net/archives/msg13937.html For partially exposed go stainless steel. Brass may be okay. Aluminum gets eaten by alkaline of concrete Hollow steel pipe protruding from concrete sweats inside & rusts Monel (74% nickel stainless steel) is best for longevity. Marine apps. Plastics like PVC get killed by UV and have dif rate of expansion See boat hardware catalogs. Design attachments so can be replaced later as wear out and make them robustly Build own plastics with A/B epoxy & glass. Delron is stronger than nylon and machines well and can be gotten with UV inhibitors. Urethane plastics bad. Or use rock [wvj] FerroCloth: Richard McCabe: http://ferrocement.net/archives/msg13918.html Polyester (or polyethylene?) 30" rolls landscaper's cloth, cut to 1' strips if needed, pure portland mix, dip, saturate, mache. Possibly use multiple layers. Then put concrete over this. Might be good for getting a mesh going. Not structural. Fibers http://www.ferrocement.net/archives/msg04448.html Glass may deteriate quickly. Carbon best. Be careful. You can't use the regular fiberglass type fibers. They will deteriorate in an alkaline environment. The glass fibers used for reinforcing concrete are actually made from zircon. Which probably helps to explain their cost. Most fibers that come from ready-mix plants are polyethylene. PVA: Richard McCabe: http://ferrocement.net/archives/msg12687.html Use fibers for micro crack control. http://www.ferrocement.net/archives/msg04141.html polyester cannot stand up to an alkali environment: http://www.ferrocement.net/archives/msg05030.html Nolan: I posted a while back about our last spray using fibers and the problems we had with voids. I think that some of the problem can be traced to our ready mix plant using 1.5" fibers. There are shorter 1/2" and 3/4" fibers that would probably have worked with no ill effects. Loren: Loves fiber, better than steel at times. http://www.ferrocement.net/archives/msg06038.html I add fibers at the rate of a handful per bag of cement. 1.5 pound of fibermesh to a bag and you can check with the company to see what they recommend to a yard. Fibermesh Inc. 4019 Industry Dr. Chattanooga, TN 37416 615.892.7243 Richard McCabe: http://ferrocement.net/archives/msg10255.html Novocon fibers good for crack control but are thicker than dramix so not as good. Dramix mixes more evenly too. Dramix much better (structural) but need plenty of time to mix to break apart (even mix before adding to mix) Zircon-fiberglass on the otherhand are delicate and must not be overmixed. Recommends looking at Kuraray PVA fibers When asked about pouring a 60' dome on slab capable of holding up a dump truck Richard replied: I'm not qualified to answer this question, but if you held a gun to my head, I'd pour at least a [floor of] 2" 6% by weight dramix mix with 1:3 cement over 4" sand. and a 1.5" inch dome shell, same mix. Lots of fines. I'd use Acryl-60. http://ferrocement.net/archives/msg10619.html Nolan disagreed and said floor should be thicker in next post. Richard McCabe: http://ferrocement.net/archives/msg13803.html The amount of [PVA] fibers can be anywhere from 0.1 percent by volume to 4 percent. Two percent by volume is the normal amount used for high tensile strength, which is about 1.4% by weight. Half that is "structural". Half again is highly effective for crack control. RichardMcCabe on which PVA fibers to use: http://ferrocement.net/archives/msg13617.html RF4000 30mm shotcrete but too big for Tirolessa RECS100L best for Tirolessa REC15 for PVA-ECC and custom mortar - tricky, ultra-thin shells Max strength, REC15 @ 2% volume or 1.4% weight, custom mortar, damp cure full 28 days. Jim on using the PVA fibers 1st time: http://ferrocement.net/archives/msg13807.html Tossed in approximate 'right amount' of fibers by volume. Made two doors - 30"x40"x0.5" w/ 1 layer stucco lath. Laminate technique with fibers only in outer layers. Damp cure 3w @ cool temps. Doors look great but hasn't tried any destructive tests. Were quite hairy but burned off with torch. No visible fibers now. Found tiny bubbles in mix, but same as w/o fiber. Very dry mix. Will beat on test samples he made when they finish curing. Forms Plywood The best plywood is the type made specifically for concrete forms. It has more laminations and is surfaced with a hard smooth plastic type finish on both sides. Very nice stuff and not much more expensive than regular crappy plywood. But if you can make a mold out of concrete, do it. You can get the curves you want and the durability if you intend to reuse it. Richard's polyethelene forms low cost heat sealed blower: http://planetaryrenewal.org/ipr/models.html Martin Iorn's Technique of Lamination: http://ferrocement.net/archives/msg12745.html Air Forms Heat sealing polyethelene: http://www.ferrocement.net/archives/msg06611.html Richard: rotary hot-wheel heat sealer from AIE (http://www.aieco.com, about $120) I had a breakthrough. I tried taping a strip of ordinary cellophane "magic" tape on top of the poly. Since the cellophane melts at a higher temperature, I could easily find a temperature lower than cellophane but higher than poly and roll the hot wheel over the cellophane and totally melt the polyethylene underneath with ease into the bottom layer without the problem of excessive melting and sticking to the wheel (and subsequent damage). The tape would hold everything in place. I could easily melt two paths on a 3/4" wide cellophane tape. The seals appear reliable and strong, though I've yet to test them with the inflated form. I think this could even be done with an ordinary cloths iron or solding iron or $3 hot glue gun by using a light dimmer switch to control the temperature. In summary, if you want to heat seal two layers of plastic material together, put a higher melt material on top and seal through it with the temperature set between the two melting points. Update from Richard: A little more on heat sealing polyethylene. 1. Paper masking tape or the blue "painters" tape works better than cellophane tape to prevent damage and to enable welding without smearing or tearing holes. Doesn't melt. The tape can be reused over and over, so you only need 6-12 inches of tape which can be removed and repositioned until it finally wears through. Check the seal before moving on by inspecting underneath for continuous melt. 2. Sealing can be done quite well, if a little slowly, with nothing more than a cheap hot glue gun by heating through the tape from the top (no glue used). Hold the edge of the hot tip (laying on its side) against the tape and slide along slowly with a cardboard or wooden backing to press against. No temperature control necessary! Control the melt by speed only. Tried a cheap Walmart glue gun (under $2 I'm told). Control temp by speed. I can seal 4-6 inches a minute. Another update: http://www.ferrocement.net/archives/msg06611.html Rip Linton: http://www.ferrocement.net/archives/msg06617.html or seaming I use the Mini-Weld Model 5 airless welder by Urethane Supply up to about 10 mil, check out http://www.toolsource.com and search for plastic welder for the best price at about $136. Over 10 mil I use a Leister Triac PID and once you get use to the feel of it in your hand it works great. Check http://www.malcom.com for good prices on the Leister units. I also use a Weldy Power Heat Gun for welding and really do like it. Check http://www.heatgunkit.com for the Weldy line, note that this line is also made by Leister and the heatgunkit site is owned by Malcom. For some good info on plastic welding in general check out the Malcom site and http://www.urethanesupply.com both have a lot of info on welding different types of plastic. Release Agents You can use Pam from the grocery store. It's soybean based, lecithin. Motor oil works but makes it more difficult to color or seal the surface later. I just started using a wonderful new release agent called Strip 4.6 from Concrete Producers in Houston 1-800-231-6403. Water based, totally non-toxic, designed for difficult mixes with additives and will not impare future coating to the concrete. Very good stuff. Lightweight Concrete http://www.geckostone.com Most concrete is 150lb/cuft (pfc) density with 2500psi to 20,000psi Air entrained (7% air) used for increasing workability and reducing thaw freezing damage. Lightweight concrete is <120lb/cuft, trad made w/ exp shale, clay, vermiculite, pumice, scoria, etc->less strong Lightest mixes are 20 to 60lb/cuft and often made with foam. Insulating: See Heat Page Foam Cement TedB: http://ferrocement.net/archives/msg16443.html Break up the thermal conduction with isolated voids. KiethB on foamed cements: http://ferrocement.net/archives/msg16359.html Can't get 500psi and good insulation with poured mixer - requires autoclave aerated cement. 40 years ago exp showed optimized insul val & strength using eps beads with foamed cement matrix->500psi(?)@30pcf and 250psi@20pcf but no quoted insulative values given. Nolan on Mearlcrete http://ferrocement.net/archives/msg09334.html Complete saturation after 6 years of use in wall of fridge due to condensation: http://ferrocement.net/archives/msg09876.html Vapor barriers eventually leak. Must maintain excellent ventilation. Horroble experiences in Alaska with foam(urathane) holding condensation, saturating and rotting framing members, esp roofs. Urathane foam eventually becomes saturated with water. Hait umbrella seems better idea and have large mass of dry sand around shell. FC List leaned toward EPScrete over Urathane foam. Nolan suggests adding fibers to epscrete mix: http://www.ferrocement.net/archives/msg07066.html Richard: http://ferrocement.net/archives/msg13728.html PVA fibers work very well with foamed cement mortar and other low density/lower strength mix designs. As you move toward denser and stronger concrete, you have to add more fibers to attain the same result, so the weaker matrix is good. EPS Concrete Don't know the referred to additive (Methyl cellulose ether) and its availability. My limited tests with latex paint as an additive solved my similar problem of separation of styro balls and cement. I used 1 cement, 1 latex and 11 styro measured by volume. Maybe cheaper - I don't know if this was just a lucky formulation - how much variation there is in latex paints. I think this was interior flat... Patents boiled the beads rather than using dry steam as industrial processors would. The patent mentions this is one way to completely eliminate the static problem, and the beads can go directly into the mix. It also claimed the beads developed a thick skin by boiling rather than steaming, which made the concrete much stronger also. The density was higher, but that was also thrown off by absorbed water. Styropor: BASF is sending out a "packet" of EPS concrete info, maybe it's something new you should ask for. $12 for 15cuft of expanded virgine polystyrene beads: http://www.ferrocement.net/archives/msg05992.html BruceWard: http://ferrocement.net/archives/msg13777.html Compressor, tube, scrubbies, glycerin, detergent, portland w/o sand -> shavingcream foam cement Sodium silicate solution -> faster setup but careful as it can setup in mixer DougLacy: http://ferrocement.net/archives/msg13773.html Cellular Concrete makes this sort of stuff. Small foam generator is $6,000(!) If foam is too dry and not runny it will cause cement to recipitate in dry nodules and ruin mix. Recommends using Mearlcell rather than soap: http://ferrocement.net/archives/msg13783.html the quantity required of Methyl cellulose ether is 1 gm per kg of cement. If i compare this cost with latex addition, this is 1/40th of latex cost. this is for your information. Manufacturers I know are Hercules speciality chemicals (Aqualon products) and Shin-its Paul: http://www.ferrocement.net/archives/msg06534.html To produce1 cu. meter of insulative material use: 250kg. Portalnd cement 1 cubic meter EPS beads 2mm-3mm 100-125 liters water 1/4 liter dish detergent Maybe we could substitute granite fines or other small fines filler for some of the portland, maybe even 2:1. If so, we could reduce the amount of portland to maybe 4.5 * 1/3 or 1.5 sacks of cement, a considerable savings. http://www.ferrocement.net/archives/msg06472.html Christian Roux's 10 year old house with EPS: http://www.ferrocement.net/archives/msg06585.html Kieth B likes epscrete, others don't: http://www.ferrocement.net/archives/msg06497.html JJArnold: 11EPS/1Latex/1Cement measured by volume: http://www.ferrocement.net/archives/msg06686.html Andy: http://www.ferrocement.net/archives/msg06688.html How do you intend to use this mix? I take it that since you are shooting for air pockets in between the eps, strength isn't a major concern. If it is not incorporated as a structural member, but more as a filler/insulator, could you not just fill small bags with the eps and then tie the bags up to a wall with a layer of chicken wire and then ferro over that? Then you wouldn't need to mix it with any kind of binder. Nolan: 30 cubic feet of 1/8" or smaller Styrofoam beads 440-550 pounds of cement 52-65 gallons of water 8.5 ounces of liquid dish detergent. (Paul or Keith, which brand is best?) pound of 3/4" long fibers. I would use the short fibers to increase the chance that it will flow through the hopper sprayers. Try Kelcrete could substitute the detergent or in addition. Try to cut the water to as close to 24 gallons as I could to make a stiff stronger mix. Fraction3: http://www.ferrocement.net/archives/msg06903.html unhappy with load bearing capacity. Made 8" blocks EPS/latex mix. weight 22-35 lb/cu-ft From "A Pattern of Language": http://ferrocement.net/archives/msg11217.html mix of 1-2-3 cement-Kylite-vermiculite" Paracrete epsconcrete: http://ferrocement.net/archives/msg12922.html detailed article Cold Joints Alex Koster: http://ferrocement.net/archives/msg10641.html Connect cement to an old cement (new old or old old) by first applying a mix of 100% addmix and thinset which can be bought from Home Depot and then keep misted moist as you add your next layer. Other tricks are key, ridge, protruding rebar or dramix, rough surface Curing http://www.ferrocement.net/archives/msg07929.html Additives Company: http://moxie-intl.com/ Paint a coat of acrylic latex paint on outside or cover with plastic wrap, etc. Shade from sun. Max cure in 28 days. Mist concrete while curing Additives Silica Fume - dual actions of hardender (pozzolanic) and filler: http://www.norchem.com/appl-works.html Makes more CSH from CH increasing bond + strength=Pozzolanic Fills small spaces and increases packing density => greater longevity Greater density also protects rebar from corrosion as very low permeability to chloride and water Better abrasion resistance as well due to greater density(?) Many messages about Acrylic-60 and latex toxicity, head spins, very sticky, hard to cleanup. http://ferrocement.net/archives/msg10807.html Quikcrete acrylic additive at home depot I also picked up some sealant. 1 gallon covers 200 sf. Same brand. Bob Cook: vermiculite:Portland 10-1: http://www.ferrocement.net/archives/msg06265.html had some problems spraying with drying and mix 125psi 4hp. Nolan suggested turning down the sprayer pressure Nolan: Kelcrete makes concrete sticky: http://www.ferrocement.net/archives/msg06256.html http://www.kel-crete.com/ http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&safe=off&threadm=3A56D50C.75768F0D%40sprynet.com&rnum=1&prev=/groups%3Fq%3D(Kel-Crete%2BOR%2BKel-Prime%2BOR%2BKel-Flex)%2B(stucco%2BOR%2Bcement%2BOR%2Bconcrete%2BOR%2Bmortor)%26hl%3Den%26lr%3D%26ie%3DUTF-8%26safe%3Doff%26selm%3D3A56D50C.75768F0D%2540sprynet.com%26rnum%3D1 http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&safe=off&threadm=3A56D50C.75768F0D%40sprynet.com&rnum=1&prev=/groups%3Fq%3D(Kel-Crete%2BOR%2BKel-Prime%2BOR%2BKel-Flex)%2B(stucco%2BOR%2Bcement%2BOR%2Bconcrete%2BOR%2Bmortor)%26hl%3Den%26lr%3D%26ie%3DUTF-8%26safe%3Doff%26selm%3D3A56D50C.75768F0D%2540sprynet.com%26rnum%3D1 http://www.monolithicmarketplace.com http://www.makersgallery.com/concrete/links.html#suppliers Kel-Crete Super Dry Admixture is proprietarily blended and highly concentrated. (Only to 1 ounce per 94 pounds of portland cement is required). It is non-toxic, and multi-functional in that it is a water reducer, gelling agent, plasticizer, and air entraining all in one product. A number of our dry-mix producers are using Kel-Crete Super Dry per one of the enclosed mix design options. Kel-Crete admixture is compatible and enhances (reduced option) hydrated lime. There are three important facts that keep our clients dry mixed products proprietary. They are privatized labels, non-disclosures, and only small amounts are required. No laboratory in the world can find a trace of Kel-Crete admixture in a blended mix design. Kel-Flex Flexural Finish Coating is a proprietary blend of multi-polymers that is blended (1/8 to pound) with Kel-Crete Super Dry (1/2 to 1 ounce) to produce a premium one-coat plaster, premium three-coat plaster, and finish coat systems. Kel-Flex/Kel-Crete will produce a flexural finish coating that has a flexural hardness of 8-H (two points below a diamond). It has a tested resistance to over 16 stains and five acids, and is virtually waterproof. It has been tested at 10 perms for vapor breathing, and is non-toxic. http://www.kel-crete.com/drymix/drymix.html Kel-Crete Corp (800)845-1833 Foamcrete: http://www.ferrocement.net/archives/msg04651.html Glycerin blown under high pressure through series of screens 1/8" apart to make small bubbles and then concrete. Need rapid setting concrete and not react with soap/glycerin. looks like a pure cement paste mix, with no sand but some fibers might be used if the cement paste pre coats them before they make contact with the soap mix. It is also important the fibers be very soft, flexible since they could "pop" the bubbles before the cement paste sets. It may turn out paper fibers are the way to go from old newspapers. Cheapy foam machine. 5 gallon pail with lid. Bubble mix with Ivory liquid soap (add glycerin if you like) Aquarium bubblers in the bottom fed with air pressure hose through sealed hole in the top or side. Light dispensing hose (sump pump hose) attached to the top lid which is filled with plastic kitchen scrubbers. Apply pressure and watch "shaving cream" bubbles appear from hose. Add foam slowly to wet cement mortar. I think 2:1 foam:cement. But for volume, a lightweight aggregate can do better. Perlite is commonly used at 6:1 and 8:1, but is more expensive than air. I have done experiments with this and have friends who had done it. If you try to make too light a product, such as 6-8:1 the product will have no strength. It will be a good insulator until it is damaged. It can crumble easily. Lower ratios of 2-3:1 can have modest strength. I think aluminum powder is a better idea than foam and I think lightweight aggregate such as expanded clays, perlite, etc. are even better. In some areas perlite can be bought from the manufacturer for around $50/ton. Hard to beat that. EPS is really ideal for lightness, but I don't like synthetics. Konstantin Sobolev suggests: http://www.ferrocement.net/archives/msg04700.html 1. Silica Fume 2. foam cement (aluminum?) 3. basalt fines (5%, unclear about this) patent (4031285) has suggested H2O2 and suitable reactants for foaming cement. They mention that H2O2 also is an accelerant for the cement also. 35% H2O2 for $12/gal. One person's formula: Sodium alpa olefin sulfate - a surfactant coconut diethanolamide - stabilizer + borax ( retarder) 3% by weight + cement Sherri Osborne: http://www.ferrocement.net/archives/msg07084.html Venturi sprayer with fine filter over output -> foam like shaving cream. Long lasting foam that doesn't break down is the key factor. focus your energy on obtaining good foaming agent . like the polypro mesh they all want to sell large quantities. look at a site called http://www.aquafoam.com/ , do a search on foaming agents they are used to cover landfills . oil drilling , cleaning . aerated concrete. Loren's comment on tree based foamer: http://www.ferrocement.net/archives/msg07097.html Sherri/Ron: The firefigting foams are usually based on surfactants (soap) , so they reduce the surface tension of water. Which in my experience doesn't help the durability of the foam. A protein based foam has a more durable bubble. Which some of the class b fire foams have. Doug Lacy: http://ferrocement.net/archives/msg14431.html For cellular concrete I like the Mearlcell from Mearlcrete A.K.A. Cellular Concrete LTD. You can fluff it with a drill paddle with a little window screen mesh tied to it. It is $120 to $130 for a five gallon pail. Mix with 37 parts water and fluff with air to expand it 17 to 20 times. Bubblestone Richard: http://ferrocement.net/archives/msg09110.html Portland Cement, Silica Sand, Lime and Aluminum Powder. Mix lime and aluminum -> hydrogen causing mixture to rise Needs something more thought to maintain bubbles to hardening. Interesting Aggregates Ideas: http://www.ferrocement.net/archives/msg05880.html Keith B says, There's a rule of thumb which says that for general concrete work your maximum aggregate size should not be larger than one third of the smallest dimension of your workpiece i.e. 1/4" for a 3/4" slab and 1" for a 3" one. There's also something called Fuller's Curve. Conceptually, if you have a big box packed full of soccer balls, you can fit golf balls in the gaps between them, then marbles into the spaces still left, then peas etc. You start with only a few soccer balls but, by the time you are down to rice grains, you have oodles of them. Fuller's Curve tells you how many of each size you need to pack solid. In practice, you only need the proportions for about three screen sizes, and any competent batch plant keeps charts for the particular aggregates they carry and blend to suit. Finishing Fines & Water resistance Fines are stuff like sand, but often the term is used for particles that are smaller. The older cement books did not think much of finer stuff, since the "paste" often is weaker with fines then without. Over the years it was learned that some fines work, some do not. These days we use all kinds of fines, that make the concrete mix much stronger. I suppose the best way of thinking of fines is to think about dust like particles. The idea is to make the concrete more dense, so as to limit the possible channels for water invasion. More on Fines & EPS concrete http://www.ferrocement.net/archives/msg03398.html Using paint rollers to finish cement - Bo: http://www.midcoast.com/~bo/FoamRoller.html cushion effect of a thick foam roller is the critical difference from hard metal, concrete slab rolling. The flattened part of the cushion presents much larger surface area of contact. Therefore the pressure is distributed and the rolled surface fairs out slight tolerances. Slight imperfections are automatically faired or graduated and therefore hidden. Considerable curvature is also accommodated by the cushion effect and streaks are not left on convex rounded surfaces. Smoothing to an extreme Belt sanders work great, for a super finish try a diamond polishing pad on a 4" grinder. Pads vary from 50 grit to 8500 grit!!! RichardMcCabe: Fineness is achieved by using fine mortar. Use 25% fly ash and 6% silica fume (% replacement of Portland cement) and 70 to 100 grit silica sand (the higher the better) to get smoothness, density and impermeability. Best of all is to cast the shower basin in a mold: then you can get glass smooth surfaces with this mix. But I would recommend against super-smooth surfaces for safety reasons. I had a concrete shower stall as a kid growing up and it was dark, dank and scary. I would suggest using white Portland cement and light sand and silica fume as a "painted on" skim coat to make it white and appealing. Find silane/siloxane and use 2% in the mix if you want it to be truly waterproof. Xypex is not the same thing, but they have it at Home Depot and it will help heal any cracks. PVA fibers of course to reduce the chance of cracking. Others mention molding, slicking with plastic when ready for steel, super fine sanding Andy: Don't smooth your rough coat, the finish coat will have a hard time bonding. try use a pool trowel on the finish coat. the rounded edges will be easier to get a smooth surface. drywall knife will leave edges. really, it is all in the mix and your level of experience. my shower was really smooth, but I added another layer for other reasons and I had a bad mix and ended up with a rougher coat than I wanted (too much water), but it still seems to work fine. Just clean it every week to not let mold get started. I just painted my shower. grinding or sanding cement really, really sucks. avoid it at all cost. Plastering Sukhad: http://www.ferrocement.net/archives/msg06461.html lime sand morter (1:4) or lime cement sand morter (1:1:9) using white cement and sand http://www.ferrocement.net/archives/msg06469.html Two types of lime: fat lime vs strongly hydraulic lime (slaked). The latter is prefered as easier but other is better quality. Check this. Course sharp sand must be used with lime. Lime sand takes a long time to harden. Fine finish coat is made with better slaked lime in multi step process - see link. Good plastering done in two or three coats. First coat fills uneven spots 12mm thick. 2nd and 3rd coats thinner so less shrinkage. Followup with finish coat too soon causes cracking and crazing. Dry slowly, avoid drafts or exposure to sun or severe heat which produce cracks. Lightly scratch or roughen previous coat before applying next. Throwing mix on makes it adhere better than trowling it on. Spraying on may be best. Plaster work in new construction should be defered as long as possible to allow building to cure, shrink and settle. Adding Water: Konstantin Sobolev: http://www.ferrocement.net/archives/msg06067.html If strength is important, you better avoid adding water in the construction site. You could add some amount of superplasticizer to make mix workable. It is the responsibility of ready mix supplier to provide concrete with required parameters among which strength and slump are most important and easy to control (I am not considering durability aspects here). If slump of the mix delivered is less than specified in the order you could just send it back to company (and next time they will take care about slump). Alternatively you could let company staff adding the water but ask them to cast the specimens for strength tests (after addition of water). If concrete strength will be less than specified by your contract you could get your money back. Don Strong: http://www.ferrocement.net/archives/msg06252.html Concrete only gets warm as it sets up when it's in a large mass (as in a mixer truck). When it gets warm to the touch it's going off; ie. the chemical reaction of ?hydration? has started and it's beginning to set up. ie. stiffen. You can place it as long as it's physically possible, that is it will come out of the bucket, or is still pumpable. You'll know when it's no longer good because you just won't be able to do anything with it. That's when you throw it away. Cold Joints There is a lot of disagreement here. Much discussion around early June 2004 and elsewhen. Some say one hour, others 24 hours, others fiber, others paint with latex or acrylic or cement slurry. Others leave original very rough and rely on mech bond. Ref. Paramasivam from India in Singapore at Thailand conference doesn't like any special additive or paint on. Considers joinable up to 10 days later if kept properly misted. It seems the best thing is to do a monolithic spray or pour and keep moist, tent, shade, mist, wet sheets/burlap/blankets. Second best is to do 1B1's suggestion of successive orange sections to minimize coldness of joints by spraying top to bottom of one area and then do each section on either side of that. Better yet with a sprayer on the opposite side working toward you. Better yet with four at 90 degree angles, etc. Much depends on humidity, sun, temperature. In a hot dry climate 12 hours is pushing it (PaulS 20040614). Since FC thinner than RC -> pay closer attention to curing. Color is not a good indicator of curing (TedB). Keep wet for min of 3 days. Cure 7 days to 80% or 90% and 28 days to almost full cure. Cure continues after that. Stressed Skins Richard Austin: http://www.ferrocement.net/archives/msg06117.html Monoconcrete's panels: eps and cement slurry with acryl 60 or similar polymer along with polypropylene fibers. I suspect the fiber percentage is fairly high. The polymer apparently gives enough stretchiness to the matrix to allow it to handle tensile forces, a long time question of mine. I think we are beginning to realize just how little material is required for housing architecture using the sandwich approach in which the core is unsubstantial with strong skins on inner and out surfaces. Try some test panels with 4 in eps, cement/sand acryl 60 or similar and polypropylene fibers. Applied with mortor sprayer on EPS board. Their walls and roofing panels appear to have no other connection between them than the shear strength of the EPS, which it is bonded to. A wing or fuselage has surfaces that wrap around and come together to form a tube or beam if you will. The Monocrete panel is a continuous sheet, with EPS holding it together. Nolan: Let me propose the next step. This would work for a hot tub or a greenhouse. Get some sheets of beaded Styrofoam and hot melt the edges together into the shape you want. Spray on a thin layer to make a bond. (one could build Bo's almost free sprayer for this) After it has set you now have solid object. You could overlay 1 layer of metal to give some impact resistance and then 1 more thin coat of mortar. Paint or seal. Nothing to complex. very inexpensive. Concrete on wood: http://www.ferrocement.net/archives/msg06969.html mxSteve (La Yucca/flyingconcrete): The underlying wood will rot ,quicky, even in AZ. Put in pillars every 3 ft on center.Assume no support from wood after 3 ? years. I'd vote for one layer of #66 10 10, and one of chicken wire. 3/4" thick. bent over nails and metal bottle tops as spacers. Granite Fines & Clay in mix http://ferrocement.net/archives/msg10586.html Bo: Fines are good if one can "surround" each grain with Portland. The easiest test is to make thin "wafers" to test for relative breakage ease- by hand. For controls, also make same thin wafers with known standard mixes. Ensure damp cure. Clays are likely finer than Portland cement, so a few % ratio has been suggested as rule of thumb, not to exceed. On the other hand it depends on application- for smoothing and stickiness, clay is great. Health Issues: Fly Ash & Silica Fume should be handled cautiously: http://ferrocement.net/archives/msg13697.html Protective mask, gloves... Use in slurry. Possible toxic, radioactive, carcinogenic components! Flyash, silica fumes, granite containing radon: http://ferrocement.net/archives/msg14722.html So vent well - only solution I see. I am going to have rock in house. Vent under to out and vent inside out with good invents. Like background radiation: http://ferrocement.net/archives/msg14726.html Engineered Cementitious Composites ECC: Supposed to be much better than standard concrete at handling stress, not cracking badly, not spaulding, etc. Basically: Specially Coated Fiber (e.g., PVA) + high cement content + Fly Ash (to reduce cost) + Rebar From report by Li: http://www.engineeredcomposites.com/publications/li_DFRCC02.pdf The additional cost of ECC over normal concrete derives mostly from the use of fibers and higher cement content. This is the reason why optimization of the composite to minimize the fiber content is so important, as pointed out in Section 2 above. In comparison to steel fibers used in many FRCs, polymer fibers such as PVA may be more expensive on a unit weight basis. However, it should be noted that polymer fibers have density six to seven times lower than that of steel, and it is the volume content of fibers and not the weight content which governs the performance of the cementitious composite. Partial substitution of cement with industrial by-products such as flyash should further reduce the cost of ECC, although the resulting change in interface and matrix properties and their effects on composite strain capacity should be carefully examined. RichardMcCabe: hinted at new PVA-ECC formulation: http://ferrocement.net/archives/msg15040.html Stains: http://ferrocement.net/archives/msg15530.html Glossary: PAHS - Passive Annual Heat Storage AGS - Annualized Geo Solar FRP - fiber reinforced polymer FC - Ferro Cement, Ferro Concrete RC - Reinforced Concrete FRC - Fiber Reinforced Concrete FFRRC - Ferro Fiber Rebar Reinforced Concrete :) ECC - Engineered Cementitious Composites PVA - PolyVinal Alcohol Fibers 1 MPa = 145 psi 1 N/mm2 = 1 MPa Books: Antoine Naaman's book, "Ferrocement & Laminated Cementitious Composites." You can order it online from http://www.technopress3000.com/. Ted Baumgart on overbuilding - general but interesting ramblings: http://ferrocement.net/archives/msg14083.html PAHS PAHS: http://www.ferrocement.net/archives/msg06712.html Passive Annual Heat Storage Improving the Design of Earth Shelters by John Hait PAHS building is designed to collect sun and sink excess into thermal mass for later use. Earth, rock, concrete, water, salts, etc. @ Mean Dewpoint > summer temp goal -> condensation @ Mean Dewpoint >> winter temp goal -> condensation Ave Seasonal Mean Temp -> ground temp @ Ave Seasonal Mean Temp < goal temp -> make "Hait umbrella" around thermal mass to seperate from earth (decoupling) Earth Tube Ventilation may be integrated with PAHS. Especially useful in our climate for warming winter air. Insulation should be outside of shell and slanted down & out at 45U. Typical rate of conduction of annual temp swings penetrate 20' down, sideways & up with most effect in top 10'. Thus umbrella. Water steals heat. High water table is bad. Rain penetration is bad. Umbrella protects from water from above. Keep mass dry. OK if water stays put but doesn't unless contained (pool). Beware of clay as it is a good conductor. Control & deflect surface water. Kieth B: "The hardest part to understand of John Hait's message is the crucial importance of the rates of thermal movement. That area bites you in lots of ways in a small installation while being what lets you live, comfortable and almost energy cost free, in a big PAH one." Intersting house: http://www.williamlishman.com/underground.htm John Burrit: http://www.ferrocement.net/archives/msg07862.html http://members.aol.com/mraichyk/OuterSpace/CulvrtHs.htm PAHS is essentially placing an insulation "umbrella" over and about 15-20 ft. beyond a typical earth sheltered home. 20 ft. is the nominal distance that heat migrates through typical soil in half a year. The insulation umbrella has the effect of raising the temperature of the earth, in which the dwelling is embedded, up significantly from the average (approx. 50 degrees). The insulation is, of course, covered with more earth. Takes ~2yr to stabilize heat swing. Ron & Sherri wrote: http://www.ferrocement.net/archives/msg07867.html One aspect of Pahs that I take issue with is the 15-20 feet of apron around the structure . I remember tests where several temperature sensors were placed in a grid around the structure to test the effect of perimeter insulation as heat storage . The law of diminishing returns , indicated that at 4-6 feet away , the savings did not warrant the placement of insulation . It would be more cost effective to double up on the insulation @ the 2-4' area , then triple the 0-2' area. Worked for Rodale group in eastern PA. Earth Sheltered Houses Tom: http://ferrocement.net/archives/msg13224.html Loves his PAHS home: 10 outside, 66F inside w/o heater mxSteve: http://ferrocement.net/archives/msg12603.html Roof needs to be 2.5" thick or more of 3000psi concrete with 2 layers of #66-10WWM Ribs are good but not necessary according to Martin. mxSteve: http://ferrocement.net/archives/msg12704.html I use #6666WW (it's NOT the devil's mesh) below, 26 ga ungal. plaster lath on top. Then 3/4" shell, then the pour with light weight volcanic aggregate. The #66 comes out and is reused. Should work great with papercrete. Let me kow if your are actually going to do it -- I have further tips not up on my site--and send me a photo to post on my site. MtnCats Tom: http://ferrocement.net/archives/msg13385.html Open plan with careful air circulation One Gone Bad as found by Nolan: http://ferrocement.net/archives/msg09488.html Biggest problem is water not diverted -> pooling, leaking, mold Also used gypsum plaster and not cement plaster -> molding and rotting Hait Umbrella: http://www.axwoodfarm.com/PAHS/UmbrellaHouse.html Bo: http://www.midcoast.com/~bo/PAHS1.html Likes Hait Umbrella, cautions on water table, says to read JHait's book. $47 http://www.rmrc.org/order.htm http://mysite.verizon.net/res086ck/selfheatinghouses/index.html Charts of various things. Likes Hait Umbrella & PAHS houses. Annualized Geo-Solar (AGS) Heating According to his charts we have: Ann Mean Temp 42-45 The Annual Mean Temperature is the average over time of all temperatures during the year. It is alsoindicative of the average soil temperature about six feet down. Why do we care? It influences the amount of insulation and type of thermal storage that you need to accomplish your goals... Ann Heating Degree Days: >7,000 Annual heating degree days is the number of 24 hour periods thatthe average daily temperature is below 65 degrees F times the amount theaverage temerature is below 65 degress. Example: If the average daily temperature is 35 F forthree days,that is3 days x(65 degrees-35 degrees) = 90 degree days. Ann Sunshine Mean Total: 2400-2600 hours Sunshine Annual Mean Totalis the number of hours of full sunshine hours we receive on average for a year. Ann Cooling Degree Days Mean Total: 101-400 Cooling Degree Days is the number of 24 hour periods thatthe average daily temperature is above 75 degrees F times the amount theaverage temerature is above 75 degress. Example: If the average daily temperature is 95F forthree days,that is3 days x(95 degrees-75 degrees) =60 coolingdegree days. July Max Temp Mean F: 70-80 Maximum temperature for the day, on average. Pretty easy concept. This tells us, along with the following chart, whether short term mass storage will be helpful or not. Mean Relative Humidity: 50-80% Average July Relative Humidity is a measure of how saturated the air is with water vapor. If the value is 35%, it is about 1/3 assaturated as it can be. January Mean Daily Temp F: 20-30 (obviously this is way wrong for our microclimate - more like -20 to 0F mean daily range) Heating Degree Days: http://www.worldclimate.com/cgi-bin/data.pl?ref=N44W072+1306+435278C Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year Month 1541 1328 1138 720 371 115 43 85 265 590 914 1370 8489 Heating Degree Days (F) 24.6 27.1 37.2 50.5 64.6 72.9 77.9 75.2 66.9 55.6 41.7 28.9 52 Ave Max Temp (F) 15.4 17.6 28.4 41 53.2 61.9 66.7 64.4 56.3 45.9 34.3 20.8 42.1 Ave Temp (F) 6.3 8.1 19.4 31.5 42.1 50.9 55.6 53.6 45.7 36 27.3 12.9 32.4 Ave Min Temp (F) 0 0 0 0 11 25 99 67 5 0 0 0 211 Cooling Degree Days (F) 2.3 2.3 2.4 2.5 3.1 3.2 3.1 3.6 3 2.9 3 2.7 34 Inches of Precipitation Other date: http://www.eia.doe.gov/emeu/reps/recmap/rec_new-eng.html Ann Precipitation: 40" Nick (Pine?) about the PAHS John Hait book: http://www.ece.villanova.edu/~nick/usenet/00000367 Soil=R1 per foot Umbrella to 20' Hait has an interesting way of providing fresh air and conducting and storing heat in the earth around the house, like this: earth earth earth earth uuuuuuuuuuuuuuuuuuuuuumbrella solar gain --------------------- <-> uuuuuuuuuuuuuuuuuuu uu \ | | \ upper earth tube uuu uu | house | \ uu lower earth tube<-->| | \ --------------------- The lower earth tube slopes up to the house (to make an igloo-like heat trap) and enters the living space at floor level. The upper earth tube enters at ceiling level, and slopes down to exit at the same outdoor level as the lower. If the house becomes slightly warmer than the surrounding earth, outside air naturally enters the lower earth tube and warm air flows out of the upper one. If the house becomes cooler than the surrounding earth, flow reverses. In either case, heat is exchanged between earth tube air and surrounding earth, storing excess house heat in the earth or removing it to heat the house. The book ends with design guidelines: Insulation/watershed umbrella: 1. Extend umbrella out and around the entire home and above also, if the home is fully earth sheltered. 2. Extend out 20 feet (6 m) wherever possible. 3. Taper insulation from 4 inches (10 cm) down to one (the first inch is the most important.) 4. Insulate the backs of retaining walls and other items that will be backfilled before the main umbrella goes into place. 5. Plastic: (6mil (0.006 inch) (0.15 mm), largest sheets practical.) a. 3 layers min. b. Separate layers with soft insulation or dirt that will drain well. c. Provide adequate drainage out the end of the umbrella. d. DO NOT stretch, but allow for settling with folds and slipping overlaps. e. Lay like shingles. f. Prevent future ponding after settling by allowing sufficient drainage angles. g. Pay particular attention to possible extreme settling and the problems that might occur given its new confuguration. h. Make underground gutters to guide water off the front and away from the building. i. Cover it with flashing if it exits the ground. Earth Tubes: 1. Size... 4 to 18 inches (4-46 cm) in diameter. 2. Length...60 feet (18 m) min. More like 100-200 ft. 3. Must go downhill from the house at least a foot plus the tube diameter. 4. Must be kept relatively level (1/4 inch to the foot for drainage in those places where heat exchange is to be minimized. 5. The greatest angle of grade must be in those areas where heat exchange is preferred. 6. At least TWO tubes must be used. a. One enters the home at the highest point where air can be taken. b. The other enters the home at the lowest point where air can enter. 7. Provide for condensation removal. 8. Provide for backfill settling so that the tubes will not be sheared off. (Backfull with gravel under the tubes.) 9. Provide bug screens. 10. A small umbrella should be provided over the tube if it is not under the main umbrella (About 8' wide, full length.) 11. Do not "short out" the storage zone of an earth tube by placing it too close to an interior wall so that conduction becomes a more prominent factor than the convection through the tube. 12. Plastic tubes should work quite well; their R-factor is small (given their thickness) and they can withstand the earth environment for a long time. Internal design: 1. Light colored walls and ceilings to spread the heat around. 2. Medium colored floors so they will be slightly warmer than the ceiling, to help avoid stagnation. 3. Carpet SHOULD make little difference [Hait likes Mike Oehler's carpet over poly film over earth.] 4. Allow for free flow of air between places where sun comes into the home and conductive surfaces near storage, so heat can be transferred by convection. 5. Provide a place for the WARM air to go. 6. Provide a place for the COOL air to go. Window layout: 1. Use moderately sized windows. Greater than the 10% required by law [?], and less than the usual passive solar recommendation. Probably about 25 to 30% of the equivalent floor area in glazing. 2. Do not localize the windows all on the south, as if it were a regular passive solar building. Spread the windows out so the heat input is spread over the whole day. 3. At the same time (be careful) DO NOT severely reduce the conductive surface area, and thus the storage mass accessibility. Adjustments: 1. EXTERNAL shading devices that are ADJUSTABLE! 2. Earth tube shut-offs and one way doors. 3. Windows, floor vents, skylights. 4. Provide for cross ventilation and high and low vents also with earth tubes. Monitoring: At least, monitor critical temperatures inside, outside, and in the storage mass. Waterproofing: Insulation/watershed umbrella. Gravity drainage. Do not allow hydrostatic pressure from water table. At least one layer of plastic as a vapor barrier. USE THE COMPLETE WATER CONTROL PROGRAM. Toby calcs: http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&safe=off&threadm=85490f%24iee%40ufo.ee.vill.edu&rnum=13&prev=/groups%3Fhl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26q%3DPassive%2BAnnual%2BHeat%2BStorage%26sa%3DN%26tab%3Dwg > Underground house with earth tubes. Approx 24' front-back, and 60' wide. > It is to be an 'Umbrella' house. For 20 feet in all directions > from the house, there will be an 'umbrella' made up of alternating > layers of insulation and plastic sheeting. This 'umbrella' will be > about 2' under the surface, and is meant to keep the dirt around > and under the house dry. It will also prevent the sun's heat from warming up the ground underneath it... Basically, you are insulating an area: (24+20+20) wide by (60+20+20)long = 6400 sqft Area the sun might normally heat in 4 summer months by perhaps 6400 sqft * 1000 BTU/sqft/day * 30day/month * 4 month = 768 million BTU's This is a very rough calculation... Some of the heat gets reflected back.. I should look at the actual data to see how far off I am --- which is probably alot... But it's something to work with... > 'Earth tubes' will be used to draw in fresh air and exaust stale > air. The tubes will travel under the 'umbrella', and around the > house in varying ways. > > In the summer, hot air from the house will rise, exit the upper > tubes in the rear of the house, and lose their heat into the dirt > around the house. Fresh air will be drawn in through the lower, > front tubes. *IF* we had 2 people (at 250 Btu/person/hr) in the house 12 hours per day for 4 months, they would generate: 2*250*12hr/day * 30day/month * 4 month = 0.720 million Btu *IF* your fridge/TV/radio/clocks/water-heater/lights/computer/etc. draw an average 15amps @ 120V per hour for 4 months, they would add: 15*120Watts-hrs * 3.41 Btu/hr/1W * 24hrs/day * 30day/month* 4 months = 17.7 million Btu's (assuming all the heat went into the ground and didn't escape into the outside, when you flow it through your tubes and exhaust it to the outside...) Without the insulation (768 + 18.4 million BTU's), I would think that the ground would heat up more during the summer months, than without it (18.4 million BTU's)... But then, you would lose WAY more heat in the winter because there would not be any insulation. So... I don't know.. What would be nice would be to have a thermal blanket which you could throw on the ground at the end of summer. [it's called snow. -WVJ] Or, build an insulated thermal battery underneath the floor in your underground house. Run your earth tubes (dirt bags?) in this battery, it warms up the dirt in the summer, then in the winter, the heat will rise up through your floor because it can't escape out the sides of the battery because they are insulated with strawbales. But that's kind of off topic from your post, so I'll spare the details... Robert's Actual experince with his Earth Sheltered house (berm): http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&safe=off&selm=aCwh4.1592%24om5.150224%40news1.primary.net&rnum=24 From: ffm (ffm@dialnet.net) Date: 2000/01/19 Subject: Re: Underground House... Newsgroups: alt.energy.homepower, alt.energy.renewable FYI for a real example, and some thoughts after living in it for 9 years..... We asked ourselves a lot of these questions, and did a lot of research before we started our owner built home 9 year ago. I thought that the dirt over the roof, while not cost effective and not calculating out as that much of an advantage, would provide the "comfort factor" to make it worth while, our budget in both time and money did not allow for this so we went with the following roof on our "walk out basement level" house. Earth Air Tubes http://www.eere.energy.gov/consumerinfo/refbriefs/aa1.html PVC, Polypropylene, metal all perform about same. Non metal hold up better and easer to install. Optimum dia varies with tube len, cost, flow velocity & flow volume. 6 to 18" excellent. Inlet should be in shady area (screened, filtered & below house) Depth of 6' below grade is idea (riiight... not here! :) Ours are about 2' to 3' below grade with 4" of foam on top. 1' of dirt = R1 so 4" foam = R20 = 20' except there are edge effects, etc. Soil temp at 20' to 100' below surface the temp is 3F > annual air temp. No optimum length, 70' works well in our tubes which raised outside air temp 70F at -40 outside and 35F Soil should be well drained Drainage holes in first 10' to 20' of pipe in ours on bottom to deal with possible condensation (never had any since 2001) Slopes downhill and make cleanable Top end can be black and exposed to sunlight to get thermal pump Government says not economical - but it is very economical if have own backhoe or doing trench for some other reason (electric) fence. J.Hait recommends 100' to 200' long earth tubes in umbrella. Four 4" pipes for each tube. Primarily Convection. Small fan if needed. Guards against radon, indoor pollutants, excess moisture/dryness. Jeanette mentions fellow in Dakota with PAHS house and earth tubes who likes: http://ferrocement.net/archives/msg13393.html Also mentions Ray Davis home from 70s which ended up sealing of tubes due to humidity in them. Tools Cement Sprayer http://www.ferrocement.net/archives/msg04133.html Reports on Tirolessa sprayer: David Grizzle: http://www.ferrocement.net/archives/msg05973.html mxSteve: http://www.ferrocement.net/archives/msg05984.html Paul: http://www.ferrocement.net/archives/msg06244.html here should have been a 'Tips' sheet enclosed with your sprayer. If there wasn't please send me youe address and I will send you another one. The factory recommended minimum air supplied to the compressor is 80PSI at 7CFM. 'Carpenter' and hobbyshop type compressors lack the ability to provide the volume necessary. They will have high intial pressure, but that will change very quickly once the air-lever is held down on the sprayer and air is flowing. The 125 or so PSI of the smaller compressorscan drop to 60PSI in a matter of 15-20 seconds when using the sprayer. Andy 20040601 (punabing@yahoo.com) just finished building his house in HI and if did again would buy good pump/sprayer. Hand troweling tough work. Would also hire some help. Did with wife. HI deals with fungus, termites, insects, rot, rains, hurricanes, earthquakes. Fell off roof but was okay. [Should use a climber's harness like I did for the pole work. -wvj] House is basically a ferro-cement water tank with windows and a door. See house at: http://eric-randall.com/AndyBingham/ http://mysite.verizon.net/res8hec7/ http://mysite.verizon.net/res8hec7/id3.html Doug Lacy House 20040531: For Sale $125,000 on four heavily wooded acres. 1 bedroom cottage and shed. 'hand-crafted' (ugly) http://s95170375.onlinehome.us/webdata1/1086039396.html http://s95170375.onlinehome.us/webdata1/1086039717.html http://smithrealestate.com/images/19559.html Ron: http://ferrocement.net/archives/msg14667.html Pumpers usually put some clay through the line first to add a little "slippery" mxSteve: http://ferrocement.net/archives/msg14682.html Helped buddy train 7 man crew, averaged 22sq M/hr both days, walls only, half on scaffolding Sprayer was running half the time. Tirolessa claims 30 M/hr - Steve suggests 4 sq M/worker/hr is good which is 2.5x by hand Celilings are slower - angled version better for ceilings. RichardMcCabe: http://ferrocement.net/archives/msg13649.html PVA REC15, mortar mix, drill attachment for dispersion in bucket, flyash, prewet fibers(?) before adding He says mortar mixer maybe but other people say no, fibers will catch and that corkscrew is better. Paul: http://www.ferrocement.net/archives/msg06059.html Main points: Only need to coordinate 2 pieces of equipment, sprayer & compressor. Sprayer can be built for $20 (1 opening) or bought (Tirolessa) for about $200 (4 opening) Compressor can be rented by the day 5HP 7cfm 80psi Can apply morter a little at a time and stop when you want Can shoot 1" and then gunite or pour additional over that Paul: http://ferrocement.net/archives/msg14582.html I generally spray at 85-90PSI using a 7HP cmpressor with a 40 gallon tank AndyB: use 1oz kelcrete per sack portland, nylon fibers, seal surface next day or same day with kel-prime to seal in moisture & prepare for stucco/plaster which should be done in 5-7 days or later(?). Can use up to 5/16" aggregate - mxSteve used 3/8". Did pool with 3 passes, 3 hours apart, ~1/2" per pass.http://www.ferrocement.net/archives/msg08564.html Nolan: me and a helper can easily spray a 22' dome in an afternoon [using the Tirolessa]. This means no cold joints. RexTarr: http://ferrocement.net/archives/msg10844.html Tirolessa modifications: 1/ a handle on the hopper, similar to a regular bucket handle, attached via holes drilled in the hopper sides. Holding this handle instead of the (pipe) handle keeps the hopper upright, so you don't accidentally spill a load. 2/ a nylon shoulder strap from that handle to the stem of the sprayer near the trigger. 3/ An insert in the hopper shaped to go around the four air outlets. Using the sprayer, you will notice where some mortar remains after the rest of the hopper is emptied (sprayed); a custom shaped metal insert placed in that area helps with efficiency. I'll probably use JBWeld to place the insert once I have the shape correct. 4/ a sheet metal extension on the top side of the hopper, on the business end (furthest from operator). This is an extension of the hopper; imagine a taller hopper on the front end and you have it. You may want to duct tape it in place in case you need to remove it to get into tight quarters, etc. Gary: http://ferrocement.net/archives/msg14580.html Didn't like the Tirolessa. Switched to a mortar sprayer. Compressor was too small, didn't get his mud mix right. mxSteve told Gary: http://ferrocement.net/archives/msg14586.html Compressor too small, start with simple mortar mix, a little extra cement to be stickier, screened sand, cement, lime, spray at 90psi, be happy, later try exotics. Home Made Hand Sprayer and Mix: (Stucco) Version 1 and pressure info: http://www.johnkingsley.ca/strawbale/sprayer/v1.html Version 2: http://www.johnkingsley.ca/strawbale/sprayer/v2/index.html Plans 2p1: http://www.johnkingsley.ca/strawbale/sprayer/v2/plans/sprayer_v2_1.html Plans 2p2: http://www.johnkingsley.ca/strawbale/sprayer/v2/plans/sprayer_v2_2.html Building & Operation: http://www.johnkingsley.ca/strawbale/sprayer/v2/tls.html Using a sprayer: http://shop.store.yahoo.com/mortarsprayer/diforuse.html The mix we used was 6 sand - 1 cement - 1 lime. Paul mentions in his article that the leanest he could run his sprayer was 12 - 1 - 1/2 before he got a sand pack (the sand settles and makes a very dense clot). Speaking of sand ... be sure your sand is stone-free! We had clean sand but it was moved by a backhoe from one spot to another and picked up some stone in the process. The stone gets clogged in the sprayer's 5/8" orifice and slows down work very quickly. We ended up screening all our sand by passing it through a sieve made from stucco lathe nailed over some 2x4's. We used polypropylene fibers in our mud and it went through the sprayer with no problems. I'm not sure if chopped straw will work - someone should give it a try and let me know! (you might need a bigger orifice) After stucco has been applied to an area, it should be lightly troweled. This troweling is to cut down the high points and fill in the holes. If it is not troweled before it stiffens, the wall will not be as smooth as it could have been. While troweling on a straw wall, straw will stick out. Dont worry about the straw that is sticking out. Do not slick the wall down. If a steel trowel is used and the wall is slicked, the fines (cement) come to the surface. As they dry and hydrate, shrinkage occurs and cracks show up. Trowel as little as possible at this point. A wood or manganese trowel will leave a rougher surface. Allow the stucco to cure for at least 48 hours before adding the second coat. This will prevent any plastic shrinkage cracks that may form in the first coat from passing through the second coat. galvanized diamond mesh is superior to cheap, galvanized, chicken wire Nolan on Tirolessa: http://ferrocement.net/archives/msg09847.html I have mainly shot sand/cement mixes with a bit of lime. 1 bag of cement and 1/3 bag of lime. 2 tests to judge ifthe waterwas just right. We would roll it into a firm ball that you could toss around and it would keep its shape and then we would throw it on the wall to see if it would stick. Not very scientific butI hope it will describe the feel to you. I would scoop the hopper full from the wheel barrow. Sometimes if it is dry enough that just air was rushing out below the mortar, I will shake it a little to help it settle or tap the hopper on the side of the wheel barrow. Thehosethat I used hasbeen aminimum of 3/8" with 80 psi on the regulator. Rebar Tiers: U-Tier http://www.unitedequipmentsales.com/rebarutier.htm Battery operated, 5lb, 200 ties per spool up to 3/4" rebar Nylon Strapper: $15 + $5 resupply 590' 100 locks: http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=40579 Mixers in a 5gal pail using motor and rebar blade: http://www.midcoast.com/~bo/BentRebarMixers.html Make our own 35 or 55 gal drum, hydrolic motor on tractor bucket. OneBone HoleHawg: http://www.ferrocement.net/archives/msg03618.html http://ferrocement.net/archives/msg13762.html Brent: Drill press mixer - trash can, paddles, 2yards in 2 hours no sweat: http://ferrocement.net/archives/msg14222.html Compressors Motor Vibrator The mortar vibrator is a converted orbital pad sander, not a drill. They are also known as finish sanders, Makita makes a good one. Instead of a sheet of sandpaper, you place a piece of sheet metal on the sander and hold it briefly into the mud that you want to vibrate. It will cause the mud to penetrate wire mesh like nothing you have ever seen before. Another vibrator suggested is the $39 massage handheld units. Another for deep vibration in forms is a squiggly wire on a drill. Tools Pneumatic hog Ring gun: http://ferrocement.com/tools.en.html Hog ring pliers Bo: http://www.ferrocement.net/archives/msg06926.html Richard: http://planetaryrenewal.org/ipr/examples.html Can spin both ways, works well in 5 gal plastic bucket or wheelbarrow. Made by wrapping metal stock around small diameter pipe. I would think one might want to spring harden it after forming. (Flame & rapidly cool) Swimming Pool Trowels: available at most lumber yards & Home Depot, larger size better and still easy to use for putting on final smooth coat. $25 in 2001 WA state. Get the flexible one, not the rigid one. Not as good for leveling though. Parker Hydraulic Motor: http://www.surpluscenter.com/item.asp?UID=2004051616310359&catname=hydraulic&item=9-5908 3.0 cu-in per rev displacement, reversible, 1" x 2.5" shaft, 1/2" NPT ports, 678 rpm @ 9GPM max, 946 in-lb torq intermittent, 693 in-lb torq continuous, 2400 psi int, 1800 psi continuous. Low speed, high torque hydrolic motor. $149.95 new Mudslinger. It is manufacturered by Hyde Tool Company, having their number 46565: http://ferrocement.net/archives/msg09755.html Nolan's favs:http://www.ferrocement.net/archives/msg00500.html Marsha: Tie gun: http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=40579 Wire Crimping Tool: http://ferrocement.net/archives/msg13560.html Ted: http://ferrocement.net/archives/msg13564.html says don't use rings as they don't pull tight enough says crossing rebar must be tightly touching to avoid lever action suggest using tie wire, plain, uncoated, doubled suggest var speed elect drill with 2prong attachment Design Some useful checks to be performed on a project: 1. Always plan the activities in advance 2. Prepare the detailed estimate of the project. 3. Check all the architectural and RCC/structural drawings from time to time before starting the actual work or the phase 4. Prepare the bar chart of the entire project 5. Calculate the monthly requirement of the Cash inflow for the project. 6. Draw a graph of Cost against the Duration. This will enable you to know the monthly requirement of the fund.. 7. Prepare the approximate reuiqrement of materials per month. 8. Prepare the ordering schedule for major items i.e ABC items. 9. Identify the vendors and contractors and make an enquiry from them regrding the rates. 10. Generally the Labour contracts are awarded on built up area method. 11. Before awarding the contract check the following things:- 1. Arrive at a general rate from the estimate before strating the discussions with the contractor. 2. Check the old records in the office and prepare a comparative table for your referance. 3. Arrive at a rate which is acceptable to you and the contractor. 4. Finalise the mode of measurement and the payment terms. 5. Clearly mention the retantion amount and Income tax deductions 6. Prepare the work order including the above points. Barrel Vault: mxSteve: http://ferrocement.net/archives/msg13639.html 18'x14' 70lb/cuft light concrete 1200psi R0.5 2.5" thick 1 layer #6666WWM Assumes dead load 50lb/sqft, live load 50lb/sqft Vault=have circle Tensor bars are 2 each #4 rebar with saddles every 12" in 3" thick x 10" wide pour of 2500psi concrete Has ribs every 10' of 10" deep Has 8" dia columns. Side beams running 18' length are 4 each 3/8" rebar with 6"x6" saddles every 10" in 8" pour 2500psi concrete Already built it and guaranteed for 400 years, now he wants to know if he was right. :) Also wants to know about end beams that keep the vault from spreading. DougLacy gives a seat of the pants answer: http://ferrocement.net/archives/msg13662.html Basically mxSteve has lots of leeway at the current arch (14') but at double that it would be another question. Martin Iorns: http://www.ferrocement.net/archives/msg05934.html Ribs not necessary on barrel vault. Metal lath needed only within 3mm of upper and lower faces for crack control. Reinforecement can be layers of 6x6 10guage Welded Wire Fabric (Mesh) (WWF or WWM). Best method is to apply mortar to lath either by spray or stiff brush push broom. Add more laminations of mortor and lath as you proceed. Paul: http://www.ferrocement.net/archives/msg05933.html FC = Ferro Concrete, RC = Reinforced Concrete E-lath is specifically for reinforcement under tension - that's its purpose. RC has slightly better compresive strength than FC. Hollow FC column with RC fill -> 20% stronger than either alone. I would build my arch or vault with FC and add rebar and concrete for a hybrid element. The FC takes up tension and the RC resists compression. Paul: http://www.ferrocement.net/archives/msg05931.html FC can be flexed more times than RC. FC fails more gradually and predicatably than RC. mxSteve: http://www.ferrocement.net/archives/msg05878.html Likes rounder than flatter domes and barrel vaults. Dealing mailing with compressive forces and be very careful during back-filling as it can cause uneven forces. Brace the structure! Says figure lateral load as 1/3 of vertical load at any depth. For basic load calculations, figure 125pcf for soil and lightweight and 150pcf for your reinforced ferro. You aren't going to have much load with 1 ft of soil, maybe 2 psi. If vehicle or other traffic then consider you are designing a bridge. Like arched culvert and those are designed as corrogated tubes for most strength. mxSteve is not an engineer but his sister is and much of the above is passed from her. mxSteve: http://ferrocement.net/archives/msg14121.html Meteorite tests convinced him two layers #6666 WWM (66-10) for earth sheltered barrel vault Now things even better is PVA in combo (I think that is what he meant) Andy concures: http://ferrocement.net/archives/msg14128.html 6x6x6 + 6x6x10 + chwire out + lath inside + 1/2" rebar armature rock solid Geodesic Domes: http://www.ferrocement.net/archives/msg03853.html domes made of sheet metal and ferocement were consistently successful, as were bent plywood pods. sheetrock(don't use it!), leaky skylights (don't use them either), insulation(Astrofoil aluminized bubblepack works for me, combined with big air pockets) False Rock: http://www.2ndnatr.com/instructions1.html Ponds: RexTarr - made pond - Long article - Fabric dipped in cement: http://ferrocement.net/archives/msg13604.html Bathtub: Mold, release agent (used motor oil works, 30W). Using adequate wire mesh, the proper ratio of water, cement and sand and proper curing of the element will all prevent cracking. Use 1 part cement and 1 or 1.5 parts clean sand with only enough water to make a workable mix. Plasticizers will increase fluidity and workability of the mix. Proper curing is to allow the piece to cure on or in the mold for at least three days, keeping the piece covered in plastic to hold in moisture. For the bestcure immerse the piece in water after removing it from the mold for another 7 days. Bo: If you have had a chance to look at a few boat building books (in ferrocement) you will have some good ideas for a sink. In your case you are concerned about the inside rather then the out side surface. The reinforcement is the same. Most sinks have rounded corners so they are easier to clean while under use. A simple plywood box mold would work well, and I would recommend rounding out the corners by cutting away the corner and repairing with auto body putty and fiber glass. Then I would get some candle wax from the craft store, melt it, paint it on. After it has cooled, I would lightly sand it down smooth with some open grid sanding material. That is the stuff that looks like bug screen made for rough sanding. The final smooth job would be placing the whole think in the oven for a few minutes at around 160 degrees. You should end up with a glass like finish. If you have no open groves, holes or other finish problems, your mold is ready for use for ferro. If you take some care to not damage the wax coating, a thin 1:2 sand mix carefully placed over the mold to 1/4 deep should give you the proper base skin. Once it has set up some (2 days?) you could carefully place some 4x4 mesh over it (2 layers) with some heavy wire along the edges, tied to the 4x4. Then carefully plaster that to the first sand mix layer, or ferro skin. I would recommend at least 1/4" of sand mix over the wire to ensure a good coverage. That is 1/4"+ the thickness of the wire layers. The outside work will not be seen, so it is the mold that is your appearance work. Just don't forget to work in all your faucet holes, drain holes and such before, cause making holes later is not practical. It will also most likely damage the sink. Another reason ferrocement sinks are not very practical is you can not crank down on the faucet nuts, since it might cause the ferro to crack. It is very hard to get ferro to accept much localized pressure like is down with nuts and bolts. In your case you need to use silicon sealer to make a gasket, let it completely cure, then crank down on the faucet nut just enough to squeeze the silicon gasket a bit. Same deal for the drain. If you do go through the process and make a sink, I sure would like to hear of the details. Working with thin ferro that requires connectors like faucets is a bit tricky. 1) I used free forming methods, no mold on mine, just a mesh cage sewn together and integral with counter surface. 2) Any molding i do now is with "parting agent" as in sand mold, the mold material surface comes off to be part of finish, (endless artistic experimentation). Cement is cheap, you need to experiment first and fearlessly, but read up on basics in any textbook first. 3)Cracking is generally due to excess water. "Perfect" water ratio is difficult to work, paradoxical! I tend to cheat with sand molds since they can absorb excess water, especially if you use water reducer which jumps out to sand. 4) I like rubbing just prior to set, but sanders work, after set. 5)This list has discussions on reinforcement, search through archives and scale your size according to discussions. white marble sand and white cement. Mix 1-1/2 parts sand to 1 part cement. Use acrylic binder for adhesion and water reduction in the mix if you like. Most people don't but they probably should. Apply a first coat over the entire surface. In about an hour or so it should have taken initial set. Apply a second coat and as start to sculpt your masterpiece. Use trowels, spoons, sheets of 20 mil plastic (they make great trowels, drag them over outside, rounded edges) anything to smooth and even things out. In a few hours, depending on the temperature and humidity, the plaster will feel hard enough that you can fill the tub with water without the cement washing out. Leave it full for a week if you can. If you want a smoother-than-baby-butt finish you can polish the marble with diamond pads. AVOID EPOXY POOL PAINTS. They suck. Peter http://www.ferrocement.net/archives/msg04853.html See Smooth finishing. Doors: Advantage of FC door: stop fire, decay proof, security door, freeform mxSteve: http://ferrocement.net/archives/msg13638.html 1.5x weight of oak -> big heavy hinges needed. Weld a ring around the inside of the frame of 1/4" pencil rod to attach lath to. http://www.geocities.com/flyingconcrete/ Recommends PVA Try light concrete, epsconcrete, foamconcrete, dual skinned "Bag End" Painting by John Howe: http://www.fortunecity.co.uk/library/fantasy/11/bagend.htm It had a perfectly round door like a porthole, painted green, with a shiny yellow brass knob in the exact middle. The door opened on to a tube-shaped hall like a tunnel: a very comfortable tunnel without smoke, with panelled walls, and floors tiled and carpeted, provided with polished chairs and lots of pegs for coats and hats--the hobbit was fond of visitors. -from The Hobbit Ted: http://ferrocement.net/archives/msg15033.html 1/8" skin PVA-ECC skin on EPS foam core is good with metal tie throughs every foot or so. Estimated weight 65lb to 100lb Loren mentioned his doors hinges flexed into foam - reinforce better, also suggested X brace - rebar welded [wvj] Walter: In our extremely cold winters I would want: carbon or nylon tie throughs for better R value and thermal break embed 6 pane window in process. 2" thick EPS instead Doug: http://ferrocement.net/archives/msg15100.html Uses long thing bolts from hinges to other side through foam core. 70lb door with five tempered glass windows. Brent on Mold Making: http://ferrocement.net/archives/msg15851.html painted a door with high gloss elastomeric paint, no release agent, made rubber (latex?) mold, cast cement in it. Didn't try to save mold. Some release agent would have let him do so. Sprinkler Systems: PVC based residential? Insurance effect? Counter Tops: http://ferrocement.net/archives/msg10453.html Cast against smooth plastic c:s of 2:1 and lots of fines. Use stains. Keim mineral paint to seal which precipitates silica Hypoallergenic Maybe use granite or marble fines PeterE: http://ferrocement.net/archives/msg10478.html Likes Siloxane sealers AlexisK mentions Glaze & Seal: http://ferrocement.net/archives/msg10491.html Has a wet look but requires annual recoating due to scuff marks RexTar: http://ferrocement.net/archives/msg13801.html 1.0 parts white portland cement 2.0 parts sugar sand 0.38 parts water 0.02 parts Rheobuild 1000 superplasticizer added last All by weight Consistency of runny cake batter. Total slump. Mixed with mortar mixer. Vibrated to remove small bubbles Notes: adding plaster of paris weakens concrete. Worked over w/ steel trowel again next morning (12hr?) and removed wood frame & tooled edges. Counter top ended up too sandy, should have used finer sand (he says) and floated more (I say). Rob O'Donnell: http://ferrocement.net/archives/msg13823.html Milestone: www.artisanfinished.com or milestonehpc.com - portland+high powdered acrylic + pigment, then apply sealers and wax RichardMcCabe: http://ferrocement.net/archives/msg15785.html key is super dense strong morter via particle packing down to very fine sizes Very fine sand ( 90 silica), Premium fly ash (Boral 3) or a premium metakaolin (PowerPozz) 8% Silica fume 2% silane/siloxane solution for impermeability - might be able to use acrylic, cheaper but not as good 2% by volume PVA REC15x6 (bien sr) for structural support White portland Cement Says 1/4" to 3/8" thick is enough Probably never need maintenance other than wash down For really cool, cast over a mold to yield a glass smooth final surface Water Tank: http://ferrocement.net/archives/msg11218.html http://ferrocement.net/archives/msg12084.html Aquaponics: http://www.ibiblio.org/ecolandtech/links/start-392001/msg00415.html http://www.i55mall.com/aquaponics/ Diving Board: http://ferrocement.net/archives/msg12794.html Beams: http://www.ferrocement.net/archives/msg06979.html Basically wrap wire around an old wooden beam or air form, add wire & cement. mxSteve's Ferro UG Cement Wine Cellar: http://www.ferrocement.net/archives/msg07030.html 24'x40' w/ central 8"x16" beam down length -> M shape Used two moveable forms to pour 10' sections at a time. Masonite covered with 6mil plastic. Arched trusses of 1/2" and 3/8" rebar 2' on center. Chicken wire over plastic on forms 1" light weight concrete (expanded shale and vermiculite) 2 layer #6666 sep by 3/4" ladder spacers. 1/2" rebar bent 60 then 90 -> vertical ribs triangular Ribs are 10" high but would do 8" next time. Lapped pours at ribs. Poured 2.5" concrete over all this. Poured columns, beam and first vault from single truck of 7 sack, 3/8" chip, 2" slump and vibrated it like mad with 2hp pencil vibrator. Had minor blowout.Ideally would have a different vibrator for membrane (vault) areas vs columns/beams. Five day cure and then moved forms. 2nd and subsequent vaults poured by hand from mix made up on site. Misted for 2 weeks. Filling ribs was a challenge Jurek's Torus House: http://www.ferrocement.net/archives/msg06296.html #3 rebar, 12" grid, 3 layers chicken wire both sides, sprayed paper concrete (yuk! -wvj) with Kel-crete admix. 12" of carved layers of EPS sprayed with papercrete and then painted with ceramic paint for insulation, waterproofing and looks. Paid $60/gal to Monolitic for Kel-Crete (2001, same in 2004-5) Swimming Pool: http://business.vsnl.com/mgadre/default.htm Counterforts at 1m on center anchored in base foundation Additives like hyproof and plastermaster by roff were used in the MIX. Sukhad: http://www.ferrocement.net/archives/msg08200.html Recommends against lots of acute corners, make smooth to avoid leaks, uses 1:1 cement:sand at joint, avoids paints as they tend to peel and blister, esp at subgrade, recommends Xypex which forms crystals (brushed on surface in paste form) and becomes part of concrete rather than a surface skin coat, _never_ have cold joints PeterEpperson: http://ferrocement.net/archives/msg11165.html Pool heated by deck. 400' of 3/4" poly tubing. PeterRobinson: http://ferrocement.net/archives/msg11171.html Suggests use 4 runs of 100' or 8 runs of 100' each since water comes to equilibrium temp w/i first 100'. AndrewNickolas Endless Swimming Pool: http://ferrocement.net/archives/msg11581.html Loren: http://ferrocement.net/archives/msg14711.html Plaster the inside of the pool with marble dust (granite ok?) aggregate cement. Tile at water lines for eaiser cleaning. Ted: Notes on pools: http://ferrocement.net/archives/msg14713.html Likes gunite, not epoxy paint, vinyl, fiberglass, etc. Likes PebbleTec - claims 50 year life or longer. Doesn't like Plast as it is not waterproof, must be acid washed periodically, algae eats into it, must be replaced every 10 years. Tile is good but expensive. Just use around water line. Ionizer/ozonator inline with filter likes. Says next pool he makes he would do as a natural pool filtration (our system -wvj) Pay particular attention to piping system. Can cut energy usage by half if avoid 90 turns, 2" dia in drain & skimmer, keep pump and filter slightly below water level, pay special attention to flow returns and stir up water (our design is whirl to center drain for self cleaning -wvj). Uses true DC 1/3rd horsepower motor powered by photovoltics (day only?) and gets 70gpm He doubled amount of rebar as standard in construction. Double walls of rebar. 4' retaining wall, 6' masonry property walls. PeterEpperson(HI): http://ferrocement.net/archives/msg14714.html Leaks are ~always at return jet s and almost never in concrete itself due to gunite sagging when shot. Need very, very stiff mix. If want extra shell seal coat with Thoroseal before plastering. Plaster 1 white cement : 1.5 marble sand -> bright white finish which looks aquamarine under water. Cheapest way is to make a ferrocement water tank and backfill AFTER filling with water. 1.5" to 2" thick Making a Cement Tank: http://www.equipinternational.com/Rach/How_To_Pages/page5.html http://www.unitech.ac.pg/ATCDI/wtank.html http://ferrocement.com/aquaculture/aquaculture.en.html Ventilation: Air Heat Exchange Air Ducts bringing in 15 cubic foot a minute (cfm) of outside air per person Drying space for cloths http://www.monolithic.com/plan_design/airquality/index.html bringing in 15 cubic foot a minute (cfm) of outside air per person The concrete for a moderate-size gymnasium or church will weigh about 900 tons or 1.8 million pounds. The amount of heat to raise or cool one pound of concrete is about two-tenths of a BTU per pound of concrete per degree Fahrenheit. For five degrees, one pound of concrete absorbs one BTU. People like 70 to 75F 1.8 million BTUs are the equivalent to 150 ton-hours of air conditioning. keep CO2 levels within safe tolerances Monolithic Dome's = $395(!) http://www.monolithicmarketplace.com/cgi-bin/shopper.cgi?key=INCO2&preadd=action Ted makes good arguments about over engineering - my thoughts exactly: http://ferrocement.net/archives/msg13735.html Stairs: Ted & mxSteve's Adventure: http://ferrocement.net/archives/msg14207.html Beams: Doug Lacy: http://ferrocement.net/archives/msg14430.html Make beams by folding lath over 2xX etc with plastic sheath, cement, rmv 2xX, cement inside(?) TedB: http://ferrocement.net/archives/msg14433.html Points out one should use some rebar on tensors Bottom cord must be able to take full load under normal live & dead load situations In earthquake top cord and side cords will also have to be able to handle uplift and wave. Doug then points out he was comparing with wood joists. Ted then suggests putting slight upward bow (camber) in beams. e.g., make them arches which compress to near flat stressed beams. CaRon: http://ferrocement.net/archives/msg14448.html UCLA makes prestressed beams by start rebar at top of beams on ends, bottom at center like bridge spanning cable. Walter: a concern I would have is that in fires these members might fail fast... Think: 9/11 - Twin Towers - Unbreakable - Titanic... Pouring a Roof Story: Andy: http://ferrocement.net/archives/msg14669.html Gak! Didn't have enough poles supporting the roof. I would think curing the first spray on coat longer would also be a good idea in my design. Big lesson he relates: use 3x support you think you need. Uses fibers and Kelcrete in his ceiling plaster but feels is not getting strong mix. Too much water? Boats: RichardMcCabe: http://www.ferrocement.net/archives/msg09016.html Dramix steel fibers # 6% by weight (50/lb) Rebar keel and gunwales Laminated Spray in polyurethane foam for insulation & flotation? Then skin with rich cement & PVA + latex? Says uninsulated boat is too cold. Ake's boats are 18mm thick??? Keep water to cement ratio below 0.4 is key to making concrete waterproof RichardAustin adds: http://www.ferrocement.net/archives/msg09017.html Density of concrete is say 150 pcf max. Density of water is 62.5 pcf 150-62.5=87.5 pcf of extra water displacement or 1.4x the volume of cement (87.5/62.5=1.4) Add a bit of a safety factor to that by doubling. If 18mm shell use 36mm foam within it assuming weightless foam. But need to account for inner shell so go to 50mm foam with 18mm shell on outside of boat and Still need to deal with keel ballast vs floatation. Martin Iorns: World leading expert on ferro cement boat building: http://www.ferrocement.net/archives/msg09031.html Standard 3.4# per-square-yard metal lath can be obtained for about 53 cents a pound, and provides both crack control and structural strength. Of course, the lath should augmented by rebar at high-impact points such as the keel, waterline, and deck edge. RichardMcCabe: http://ferrocement.net/archives/msg15842.html Use lamination 3mm spacing ideal 5% to 8% silica fume replacing portland cement Polycarboxylate superplasticizer to reduce water/binding ratio below 0.35 Beware that thickness is not strength. Study Martin Iorns work. Good curing is essential. Acrylic helps with self-curing but still need to wet cure for all important first 48 hours. 28 days damp ideal even w/ acrylic. Avoid latex products like Acryl 60 as not reliable in aqueous (marine?) environment Ake Thorsen is another excellent boat builder: http://www.ferrocement.net/archives/msg11477.html many boats of fiber only using shotcrete rebar only on gunwales & keel 17,400psi concrete (~3x normal) Sergei: http://www.ew-assistance.com/partners/ferro/cruiser50.htm His project is 50' sailer & 50' motor sailer Internal three layers: 3x (19x19x0.9mm) Wire 3mm 100x50 (extra strong) External two layers: (19x19x0.9mm) + 2x (12x12x0.8mm) Suma(???) = 20mm Has also repaired boats: http://www.ew-assistance.com/partners/ferro_boat/ferro_boat.htm Mother Earth News article: http://www.motherearthnews.com/menarch/archive/issues/016/016-059-01.htm Thermal Expansion: http://ferrocement.net/archives/msg14871.html Material a (x10-5 C-1) Glass (ordinary) 0.09 Glass (Pyrex) 0.32 Concrete 1.20 Steel 1.24 Copper 1.76 Aluminum 2.34 Lead 2.90 Solar Parabolic Reflector - Satellite Dish: Richard McCabe: http://ferrocement.net/archives/msg15590.html Plot x=y^2 on pice of plywood. Can vary curve to focus (steam) or broad (cooking) area. At inside of curve attach pipe section. Drive rod in ground coming up several feet. Put pipe on rod (fit tight but spins) so can spin plywood curve around to create dome (spheroid). Clamp to keep from hitting ground. Pile up bricks and hunks of concrete until have lump of concrete (?) close to temlate. (I think he means around the rod.) Mix up very fine batch of concrte. Spin template around to make a perfect inverted parabola with a smooth surface. After curing, wax to make smooth and apply mold release. Now can make thin parabolic reflectors off of mold with fc and fibers. Beware of high windloads during storms on solid dish. Needs some metalic mesh within FC to reflect or metallic paint on inside surface if using for radio, for solar use white or ?. Could use iron-oxide (waste toner?) painted, flash cured or mixed with cement. [wvj] Handycapped Accessibility: Jetgraphics: http://ferrocement.net/archives/msg16429.html There are many reference guides on-line for Accessible Housing. http://www.allabilities.com/house.html http://www.pva.org/ Lights: LED solar-powered http://ferrocement.net/archives/msg16185.html LEDtronics Series SLR001 and SLR002 solar powered 12v lightning systems for indoor lighting. http://www.led.net/pages/News113.htm $365 for 10watt system. Expensive. wvj: building your own is better Railings: mxSteve's How-to: http://ferrocement.net/archives/msg16611.html http://www.geocities.com/flyingconcrete/stairs.htm Do all in one day. 1/2" rebar to shape of railing. Triangulate attachments. Wrap with 3 to 4 inches of thin ga. lath along length of rail. Wrap additional strips of lath at 45 degree angle to rail. Squeeze tight with leather glove to 1.25" Coat with fine sand cement (2.5:1) Use mall trowel & leather glove. Wait 20 minutes and then vibrate with a bagged palm sander. Recoat and revibrate until everything completely consolidated. Always dampen prev layer before applying next. Allow to firm and then scrape to reveal top layer of lath. Even out rough places with glove. Add 3/8" layer of 2.5:1 with PVA fiber 1% mix (13gm/liter of mud) to prevent cracks. Let firm up and rub smooth with leather glove. Apply 3/8" layer of fine sand polish coat with rubber glove. Damp sponge to grade & smooth before finish coat dries too much to prefent cracking. When smooth and firm, go back one last time with bare hands (???) and get smooth. Allow to cure overnight covered by plastic strips to keep moist Final smoothing - wvj Benches: dlJohnson: http://ferrocement.net/archives/msg16659.html Design Considerations for a handicapped accessible home http://www.specialneedsfamilyfun.com/accessible-home/ U The lower range of reach of a standing person is within the reach of the wheelchair user so that the location of hand controls, switches, and storage can be placed within reach of both. U For walkways, no obstructions or gratings should occur. A width of 4' provides space for a wheelchair and a pedestrian to pass and also allows for a 90 degree turn of a wheelchair. However, a width of 5' provides space for the passage of two wheelchairs and a 180 degree turn of a wheelchair. U Ramps should be developed at a grade no steeper than a 1:12 ratio. Curbs should also be provided so that a wheelchair cannot accidentally run off the ramp or crutches or canes cannot slip off. There should also be at least 5' of straight clearance at the bottom of the ramp U Entry for persons with disabilities should be at primary entrances, not service areas. Revolving doors and turnstiles are hazardous to the mobility disabled. U Doorways should be wide enough to allow for wheelchair passage. Some codes specify 34" while 36" requires less precision of the user. U Elevators should be integrated into all buildings with two or more floors. Controls should be placed low enough for a person in a wheelchair to operate. Also, a 5' diameter of the space would enable the user to turn around. U A curbless shower stall is the most convenient way for a wheelchair user to shower. It can also be used by persons without disabilities. U A side-by-side refrigerator is best for the mobility impaired and wheelchair users. Built in ovens at counter height is reachable for wheelchair users and the elderly. Cooktops should be placed at 30" is convenient for wheelchair users and others. No space should be allowed underneath because of the danger of hot spills. Sinks may be located at a height of 36". If space is provided underneath, pipes should be covered in case the user has no sensation in their legs. U dining tables should have a 4' width for two wheelchairs or a 4'6" width for four. U Handrails and grab bars should be placed no more than 1 1/2" from a wall to prevent a person's hand from getting caught between the rail and the wall. Also, bars should be 1 1/4" to 1 1/2" in diameter to allow ease in gripping. U People with mobility or hearing impairments should have access to TDD and telephone bank installed at an accessible height. U Ramps can be aesthetically incorporated into the overall design. Carpeting of the ramp also prevents slipping. U Asymmetrical doors allow adequate width for a wheelchair in a space where double door of the same width would have been inaccessible. U Desks with lowered portions that retract when not in use provide a writing surface of wheelchair users. U Entrances should be on-grade with a slip-resistant surface and awning of some type. Also, a drop-off area should be visible from the front door. U Straight staircases with resting places on the landing should be provided for those with mobility differences and who tire easily. U Light switches with large controls are easy to use and often come with dimmer capabilities to adjust the amount of light needed for task surfaces. Thermostats should have raised, easy to read numbers. Controls with audible clicks are also helpful. U Recessed lighting under stairs should be provided to prevent accidents. Careful attention needs to be paid so that the lights are not visually confusing. U Lighter color schemes should be applied in rooms with large or many windows as to prevent the "dazzle" often caused with drastic differences in light levels, and for people to recognize objects near the window. U Well-textured patters should be used on wall coverings. Slick, shiny surfaces offer no friction for stability and may cause glare that can be visually confusing. U Carpet wearablility and institutional versus residential appearance must be taken into consideration when selecting. Also, mobility of a wheelchair on certain types of carpet is a consideration. U Door closers such as automatic and delayed-action closer will allow passage for the mobility disabled and wheelchair users. U Tile with an abrasive face that will prevent slipping is a must in surface material selection. Joints between tiles must be kept small to prevent tripping. U A comfortable sleeping system with storage within reach is necessary for people with disabilities who spend more time in bed. U Tables with legs are more stable than pedestal legs, if users require leaning on the table in order to stand up. U Signs with contrast, proportion, and redundant cuing must be provided for all users. Also, tactile cues are needed for people with impaired vision. The international symbol for accessibility must be placed to indicate accessible facilities and parking. U Extra counter space should be provided in pull-out work surfaces. These also enable a wheelchair to be placed beneath the surface. U Wheel-in showers are not only easy for wheelchair users to use, but can be aesthetically pleasing and even luxurious. Wheelchair dimensions: http://www.dpa.org.sg/DPA/access/95appena.htm See Rodale Black Book by Charlie Wing. Septic in Vermont http://www.umass.edu/bmatwt/publications/articles/perc_testing.html Vermont governs on-site sewage through subdivision regulation. Lots larger than 10 acres are exempt from state regulation, but many towns control the construction of wells and septic systems with local ordinances. Lots smaller than 10 acres are considered single-lot subdivisions. Soils in single-lot subdivisions must be tested and approved before title of ownership is conveyed to a new owner. You can't break up a 60 acre tract of land into 10 lots without having each septic area approved first. An approved septic permit runs with the land's title. Four deep-holes must be evaluated on each single-lot subdivision: two in the proposed leaching area and two more in a reserve area. A reserve area must be available in case the primary system fails. In Vermont, it is assumed that all septic systems will fail, so you have to prove that you have adequate area and soil conditions suitable for two systems. In fact many states have similar provisions for reserve-area testing. Vermont's observation holes must be 7-feet deep and 4-feet below the bottom of the proposed leaching field. Seasonal high-water must be three feet below the disposal system. If the regulation offers you an acceptable range of hole sizes, pick the smallest one. Smaller->faster drainage due to area:volume ratio. Ideally do when water table is low. Having a septic perced and designed costs $1,000 to $2,000 or... become your own Septic Design Site Technician for only $55 ($100 after 20040630) Exam (written + oral) Allison Lowry DEC Principal Soil Scientist - technical contact 802-241-4455 Virginia Little, Administration & Compliance Section Chief - handles literature, web site, etc. 802-241-3833 http://www.anr.state.vt.us/dec/ww/sitetech.htm Heat Sun Chart Notes: http://www.srv.net/~tm_crw4d/opt/sunchrt.html U Only rises exactly in the east and sets exactly in the west on two days of the year - the first day of spring and the first day of fall. U Rises in a direction north of east and sets in a direction north of west during the spring and summer months (northerly latitudes). U Rises in a direction south of east and sets in a direction south of west during the fall and winter months (northerly latitudes). U Peak (zenith) at a point due south of the observer (northerly latitudes). The time this occurs is defined as solar noon. U Zenith is closer to the horizon during fall and winter months, and is higher in the sky during spring and summer months. U Rises earlier and sets later during the spring and summer months, with the opposite being true during the fall and winter months. Insulation http://www.ferrocement.net/archives/msg16520.html Reflectix, Astrofoil, foil-bubblewraps, etc make excellent outer insulation and if lapped could be water shedder that breaths due to lap joints. Put ground cloth protection outside of it and then gravel for drainage. tried the foam-in-a-can as a glue between the cement and foam sheets? I know you would have to do just spots and quickly press the foam sheet in place before the can foam started to skin over, but that stuff sure is sticky. It seems to stick to my concrete driveway too well. It might be the cement has to be very dry first, but I have notice if I spray a little foam between foam sheet and cement, then press for a few minutes, it seems to be a very good bonder between the two. I hold the foam sheet away from the cement about an inch or two, spray, then quickly press the foam sheet down. RobO'Donnel: http://ferrocement.net/archives/msg16609.html Stresses reflective foils Gary an ex-pest control man says: http://ferrocement.net/archives/msg16646.html Boric Acid should be part of foam to keep away insects and fungus. Perlite: http://www.ferrocement.net/archives/msg08893.html R 2.5 (0F) to 4.7 (100F) - Less insulative value if in cement matrix of course. 6:1 mix -> 125-200 psi R1.7 to R1.5 8:1 mix estimated at R2 Silica fume would increase density some. Perline - prob not good choice: http://ferrocement.net/archives/msg11948.html Also see Foams, EPScrete, Bubblecrete, etc in FC Insulation, Heat Movement, window shades http://www.ferrocement.net/archives/msg07243.html heat moves in three ways: conduction - high R/low U stop convection - seal up cracks, double windows, create dead air space, pockets, seperate windows by 5/8" optimally radiation - metal films stop 97%, 2 layers stop 97% + 97%*3% = 99.91% nomially FBBF Bubble wrap combines two radiation barriers with two conduction barriers and convection barrier if properly taped. Beware of condensation - need air exchange. Can get foil wrap less expensively from steel building suppliers , they use it extensively. www.insul.net makes Astro-foil Bay insulation supply Co. Alpha www.alphainc.com www.thermaldesign.com temp shield www.mwicomponents.com Microfoil www.nofp.com Reflective paints: http://www.marathoncoatings.com or http://www.new-technologies.org/ECT/Civil/supertherm.htm www.low-e.com another one superior to bubble wrap www.rfoil.com Roman Shades are a type of window treatment which folds panels horizontally by pulling up the bottom say 4" horizontal rectangle till it lifts the next 4" horizontal panel ending with a flat stack at the top of the window when fully open. Like venetian blinds but with a connecting fabric cover and a different lifting mechanism. KiethB: http://www.ferrocement.net/archives/msg07248.html For duct insulation, the Reflectrix application notes call for 1/2" spacers to separate the insulation from the duct. For a narrow space like that, air motion is inhibited, so convective heat flow is small and the space acts mostly like a poor heat conductor. Mount the insulation in contact with a surface, and you lose not only the skin effects, but also any benefit from the temperature differential across the gap of the spacer case. SteveMillerVT: http://www.ferrocement.net/archives/msg07237.html http://www.ferrocement.net/archives/msg08016.html http://www.sover.net/~triorbtl/ Likes Reflectix and Astrofoil Claims as good as 6" of fiberglass batts and immune to moisure & age. The use of tight sealing and ventilation where it is needed are important parts of this strategy. Says neighbors burn 400 gal of fuel oil/month but he burns 600 gal/year. Covers windows at night. Not much in the way of windows - dark inside. His wife "keeps house warmer than he likes". We used Astrofoil in library & Groom. Window heat shrink film Shrink-It (might be just for boats & not windows): http://www.shrinkit-inc.com/ Polyethylene shrink-wrap film is shipped in boxes, as centerfold flat sheeting. Hypercaust Air Heated Floors: http://www.axwoodfarm.com/house/Hypocaust.html Radiant Floors: mxSteve:http://www.ferrocement.net/archives/msg07874.html I've built a bunch of these in the USA using solar heated air.They all work great. Seems to me what you want is heat transfer from the heated air (or fluid). To get a good transfer of heat, blow the air through a gravel bed (8-24" deep,depending on gravel size and flow length) under the floor (slab 2-4") I can't see enough transfer happening through ferro tubes or fire hoses. Keep it simple and put the radiant floor section in the center of the room-no need to do the whole floor. 2" ridgid insulation underneath over vapor barrier. Seems much less expensive and easier to tweek than this annual heat storage idea. Ron: http://ferrocement.net/archives/msg13224.html Runs 300' ideal, 8" to 10" apart, claims aluminum unnec Wirsbo best but not worth cost. Says little dif between brands and strengths. Fireplaces/Chimneys: MezouCrete $40 55lb bag: http://ferrocement.net/archives/msg13070.html Galvinized because of zinc fumes: http://ferrocement.net/archives/msg13034.html Fiberfax blanket for inside fire box: http://ferrocement.net/archives/msg13067.html FC Firebox: http://ferrocement.net/archives/msg13088.html Super 3000 (air setting phosphate bonded mortar) watered down and soaked into fiberfrax. Rocket Stone: http://ferrocement.net/archives/msg13095.html Janoahsh: http://ferrocement.net/archives/msg12561.html To a scoop of power-station ash, add some steelworks slag. Toss in caustic soda, .... a bit of waste-water ....and mix well. After ten minutes in a moderate oven.....a quick-setting geopolymer! Can make from a wide range of materials containing mixture contains reactive sources of silicon and aluminium Bo: http://ferrocement.net/archives/msg13124.html Super30000 & FiberFrax Refrigerator/Freezer Thoughts: Use spring water to make a spring box to chill most things. Use a custom built freezer out in entry. Superinsulate both. Put thermal chill mass in both (Granite) On Freezer use an efficient 12v DC motor that can run off of a battery for days if nec. Can be very small compressor if well built freezer and heat coils cooled by spring Both should be chest access rather than upright. Vapor barrier is critical inside & out! Reflectix or similar FBBF so also a radiant barrier. InsideWall: 1/8"AirGap:ReflectixFBBF:1/8"AirGap:1/8"AirGap: Chilling Coils (Spring/Moon/Compressor) ThermalMassGranite: 6"FoamInsulation(Urethane=R7to9/inch=>R48): 1/8"AirGap:ReflectixFBBF:1/8"AirGap:1/8"AirGap: OutsideWall Condensate drains below all insulation, etc. Use Lunar collectors to release heat to northern night sky Seal all joints with urethane foam. Heavy latching lids. Small spring box for milk, juice, fruit/veggie snacks, etc with side door(?). Stainless steel for hinges, etc. Magnetic double seals Condensate drain. Easy to defrost, clean, wipe, ultra smooth finish epoxy white Glass shelves Boxes baskets StephenKeating: http://ferrocement.net/archives/msg14928.html Clay tileliners exist for this. Maybe you can stack them, and layer on the FC from the outside. Check for cracking a lot, and laminate another thickness if you need to. I personally would use about 3" of FC, so I had some real durability and thermal resistance, with a clay liner inside. The thermal expansion of steel and concrete is virtually the same, and are not dielectric.. That is why they are so compatible, and why other metals are not used SteveME: http://ferrocement.net/archives/msg14936.html 8" round shiplapped joint refractory chimney tiles are as good as 8"x10" rectangular and easier to clean. SteveMillward ex-firemarshal on Chimney & Fire: http://ferrocement.net/archives/msg14978.html burn hot for first 90 minutes to: 1. get creosote cleaned out and heat from any creosote used 2. increase flue gas velocity 3. heats up chimney liner so creosote won't be as likely to be deposited Must do this from start (e.g., don't let creosote accumulate). I would add inspect regularly and clean chimney, firebox, etc. [wvj] dlJohnson: http://ferrocement.net/archives/msg14945.html http://ferrocement.net/archives/msg15008.html Sand conducts too fast. Min 2" perlite with maybe just enough portland to get it to hold together. Lighbulb Heater: WalterJeffries(wvj): There is all of this discussion of energy efficient lights but maybe that is the wrong tact in some situations. In the winter in an earth sheltered efficient house the incandescent bulbs might give off just the right amount of heat to warm the house radiantly. Home energy systems often use either or both the hot water tank and incandescent lights to handle over production. dlJohnson: http://ferrocement.net/archives/msg16658.html Suggestion by several people about using a light bulb to heat up highly insulated/reflective ovens. wvj-This might be a good backup to a wood cookstove in addition to a microwave.