Instructables
Ferrocement is incredibly strong yet inexpensive and easy to build with. In this doghouse, I know my dog will be safe from hurricanes, tornadoes, earthquakes, and small tonnage nuclear detonations.
 
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Step 1:

Assemble a dense wire mesh in the shape desired. The surface must curve in two planes, as on a sphere or an egg. Flat plane, cylinder, or cone surfaces will not be strong. Use at least 4 layers of hardware cloth and/or chicken wire. The finished wire mesh should be mashed or laced to less than 3/4 inch thick with no holes large enough to stick your little finger through.

Step 2:

Slap on the concrete, working it thoroughly into the wire mesh, removing all voids. Excess concrete will fall through the mesh to the inside. Scoop it up occasionally and use it on the outside again. When the wire mesh is completely filled and covered, smooth the inside and outside surfaces so the concrete layer is less than 1" thick from inside to outside. Apply all the concrete in one session, to avoid a weak seam between old and new applications. Keep the concrete damp for a week by covering it with wet towels and plastic. (28 days for maximum strength).
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cathrynm7 months ago
If ferrocement is not waterproof, then why is there a large community of folks sailing the oceans of the world in ferrocement boats? Seems it would get a bit sticky the first time they dropped the boat in the water if ferrocement is not waterproof, not to mention, if you look up ferrocement and waterproof, you will find several sites that speak to the fact that ferrocement IS waterproof. Granted, you can add a waterproofing seal to ferrocement if your area is extremely humid, but you might want to check this site: http://www.ferrocement.org/ which discusses the fact that a ferrocement ship built in 1855 is still afloat. That would tel me ferrocement does pretty well in water!
dome_head (author)  cathrynm7 months ago
it doesn't leak like a sieve, but more like a sponge. See http://www.waterproof-concrete.co.uk/ for a description. If a little dampness getting through is OK, then a coating may not be necessary.
iti5 years ago
ferrocement is not waterproof. You can add waterproof agents to the mix before applying, or you can use housepaint, or roofing paints or sealers to seal it. But as it stands? This little guy will be really wet if it rains. :) Nice job building the wire frame, and mudding it. Looks great.
I seriously doubt the water will pour through an inch of concrete. If the house were submerged it would wick through, but I'm sure mr frisky will be just fine in the rain.
lol. Actually, rain will pour through 3 inches of concrete.  Lookat any road, driveway, carport etc.  Concrete is porous. You mightlike to do a google search on ferrocement, there are several excellent sites.

It needs a sealer of some form.  Because the house is curved, therain will run off, but if it rained for a week, it will  obsorb thewater, and sooner or later the saturation point will be reached andwater will run through.

It has tiny fractures throughout, over time if not checked, they grow,turning into hairline cracks, then big cracks.  Any wire insidewill rust, and expand the cracks more.  etc etc.

Sealants are required.  Just do a test, try it yourself.

Even cement walls on a house must be sealed on the outside if you wantan fha loan. Why?  because they will do the same thing, absorb therain, water from sprinklers and then transfer it to the inside.

And in the case of a sprinkler? It doesnt take days, lol. I tried this one too.  It was fun to watch and see that thepattern on the inside was the same as the outside.  I nice curve.  
I made a rain barrel from ferrocement; no sealant, no leaks.
milesnorth2 years ago
Love it! need to make a insulated dog house and this is giving me ideas. We live in Alaska and I think this might just be part of the trick. Cool.
I want to make a fort out of this!!!!! Then again, with the 3-4 feet of snow and ice that I'm buried in, I could make something similar.
anatole5 years ago
You did a nice job. A lot of work for a Dog House but also an interesting and rewarding experience I'll bet. I understand boat hulls were made similarly years ago and lasted a hundred years. In fact I read somewhere that one is still in existence floating somewhere. Ferrocement is labor intensive and some have built actual homes with this methodology. I wish I was a young man I might build a home in concrete as I think it is a very green and long lasting. Thanks for the project info, very nice! Anatole
xd12c anatole4 years ago
http://www.monolithic.com/
I would like to get/build one, but I don't have the resources :?
cd41 anatole5 years ago
i want to build a home of it now and with alot of green stuff.. maybe someday.. i would post a video or instructable of it of course!
ClayOgre cd415 years ago
Actually, as I understand it, the manufacture of cement isn't all that green. However, the stuff sure is cheap. I have considered using this idea to build an old fashioned claw foot bathtub, then just coat the inside of it with that acrylic stuff they make for refinishing bathtubs. I have also heard of people making hot tubs out of ferro cement.
In the sacred other Eath News of olde days, they did articels where people built Chord wood or bottle/can cement structures. Like this lay down a foundation /footing bring to grade or above. Then layer by layer use old bottles/ beer cans (all washed and dried)pointing the open ends into the structure (water can not fill them, should you get a leak), if you use chord wood use sold whole logs cut into say 2 foot lenghts. For a big structure youbuild a moving armature that rotates and raises, so you can keep the  dome shape (think lemon wedge, where the peel faces the wall and pivots on the thin edge)If you lay it out right , you leave space for doors windows etc. 

Cement structures take time to really dry out and some peolple compain of humidity for several years. I would think in SW USA this could be a lucky good thing, in Manitoba maybe not. 

Jest fer fun you could, with a small dome  use bottles (blue green or flint) with the ends exposed to the light so internally you have illumination.  A design even, say a constellation if it is a shed type building.  In a small structure like for the dogs you could make a two layer bottle wall (no tilt, then put your ferro cement screening and maybe 2-3 in a cluster at the top as a skylight.  If you use small bottles like mini juice things or ginseng bottles, you could do constellations and being a dog house do , errr do SIRUS, (Cannis Major).

The final coating can vary but the stuff they use to lay ceramic tiles is water proof on drying . Big bro waterproofed an entire basement with it, filled cracks and space too, so it is like hydrocement in that it filled cracks and stayed waterproof (over 10 years, no leaks). When we did the facade onhis bar/club we used it there as well.

It pays to add something to the cement mix that makes it water proof over a final coating of paint which peels.  It would be great to paint over it anyway.

A structure as small as this dogigloo might be better made with Struclite and then a finish coat of water proof cement with lotsa bonding agent. Structite is a cement mixture with styfoam and pearlite (perhaps) mixed in. With your wire mesh it should be self supporting and will be cooler in summer warmer in winter.

seeya in the funny papers

jamiebeau5 years ago
How about using a hypertufa material composed of cement, perlite and peatmoss to make it light enough to move about? Actual concrete would be a very heavy base to move about.
dome_head (author)  jamiebeau4 years ago
Would not be as strong, since ferro cement gets its strength from the compressive strength of the cement.  Make it thicker to compensate, but this increases weight.  Each type of structure would have an optimum set of compromises between weight, strength, cost, etc.  The additives would improve insulating value.
 
This is a pretty cool idea. Are there any paints that can be used on this?
Having roofed for more years than I care to share. An excellent product and compatible with most substrates is Elastomeric. Can be purchased at your local home center. Latex product cleans with water. When applying several layers use the fiberglass re enforcement mesh 6" wide roll.
You can use regular water base paint or better yet the anti fungi type like the one regularly use in bathrooms, or even better get it paint while the cement is drying using diluted paint and when it dries it will be fix forever, Imagine a dog house with murals on the walls. How cool is that!!!
thepelton vhcl5 years ago
Painting on fresh plaster is the concept for fresco. What occurred to me is that you could cover the outside with glass beads, stones or something of the like for a kind of mosaic decoration.
Trollfish5 years ago
(removed by author or community request)
MrLWJ Trollfish5 years ago
Just to clarify. Liberty ships were not built by the navy nor were they made of concrete. They were built by a number of contractors, Kaiser, Todd Shipbuiling, etc. They were built of welded steel plate, a new technology at the time as ships were built with rivets till then. The only Concrete on the ships was used as a checp version of armor around the bridge and gun tubs.
glorybe5 years ago
It is ferro-cement not ferro-concrete. The wire replaces the stone aggregate in concrete. Also to space the layers of wire some people make little slugs of cement to use as spacers between the layers. Ferro-cement can be super strong to say the very least. It is a wonderful medium and the world is just catching on to it. Homes can be built with this method.
Briguy95 years ago
I thought it only works when the dog is inside the house? lol.
studiobil5 years ago
Just a note about rust and concrete. They don't mix! Avoid using rusty metal ie rebar, chicken wire, wire ties etc. The moisture in the cement mix will help accelerate rust in the end job which will eventually cause cement/concrete "spalling" - more dramtically known as 'Concrete Cancer". Yikes! This causes the concrete to crack from the inside and eventually it fails. If you see any rust on reinforcement for construction projects etc it means the inspector isn't being tough enuff -- rust is a no-no. However unless you're building a house, hi-rise or boat, rust is probably not an issue. It can take 10-30 yrs to destroy your project! I don't think Frisky is in any immediate danger!
glorybe5 years ago
There is a huge error in this how to. Concrete is not cement. Trying to stuff concrete into this mesh will not go well at all. Ferrocement is usually about 15% cement, 85% sand and no rock at all. Water is added until the mix is a sort of stiff , plaster like, substance. Also, good ferrocement jobs require either a form or someone on the inside keeping the mix looking decent so that the mix stays within the wire matrix.
I've seen monolithic domes made with air forms inside the metal frame and allow the exterior to set up first, then go inside and finish after deflating the airform. I hope to someday build a home, but not dome style, but still stylish.
it would be awesome if you had a hill in your back yard and you put the house into the hill (except for the entrance/exit hole)..............BUNKER STYLE!!!!
watermelon7 years ago
Ever thought about using that stuff to build him a boat?
Ferrocement is used for boats, often in primitive countries. When I first looked into ferrocement for building houses, about 30+ yrs ago, in the old Mother Earth Catalog, they showed pictures of some native fishermen on the beach, making big "forms" out of hard-packed sand -- basically shaped like an upside-down boat hull. Then they'd lay chickenwire over it, tightly woven, and start packing in the ferrocement with trowels. When it was cured, they'd flip it over and have a boat. In the old original Mother Earth catalog they showed people who'd made their houses of ferrocement, and often many of the interior walls and furniture (or at least chair and couch-like platforms to hold cushions. For big projects you need to use re-bar to hold the chickenwire skeleton stiff. Some say you should really use thicker, stronger mesh than chickenwire for larger structures, but it probably doesn't make much difference as long as the cement coating is thick enough, or unless you're aiming for a 40-yr lifespan for the bldg and it takes a significant load. CAUTION: When you pick the chickenwire or welded fencing wire for the skeleton, make sure you do NOT use the newer plastic-coated stuff. While it might seem like it would hold up better, I'm pretty sure the cement will not bond to it properly. Using dirty or rusty chickenwire is also a no-no. Some cement guy who does a lot of re-bar work could probably also give us some useful hints on tying the wire, etc. I believe chickenwire is sometimes available in different gauges, like chain link. Obviously you should use the heavy stuff if your structure is bigger than a doghouse.
What is the problem with using rusty wire? I'm building some steps, taking a long time, and the re-bar is rusty... ... is this going to cause issues?
A little bit of rust is actually helpful, because it makes a pitted surface. Too much rust forms a dusty/flaky layer that helps the metal slide within the concrete, and is therefore bad. If you're doubtful, take a stiff brush to the armature, and knock off anything loose. --Goedjn
Rust is corrosion. Rust will continue inside the concrete until your chickenwire base is powder. Ever see an old ship with orange streaks on it? That is Rust, and it is causing the ship to degrade to powder.
I was hoping someone really experienced in cement would answer this -- I don't really feel qualified. Since chickenwire and smaller-gauge stuff is so thin, I believe rust is more of an issue, since there isn't much metal to begin with. For regular rebar, I don't think minor surface rust is a real problem. I've seen somewhat rusty rebar laying in the trenches for footers, before the concrete truck arrived, and no one seemed concerned, including the inspector that approved it. Once the rebar is dropped onsite, it's often many days before it actually gets installed and covered with concrete (sometimes even weeks), so apparently the surface rust isn't an issue there. I do recall reading, decades ago, that rusty chickenwire should be avoided in ferrocement, but I'm just guessing that the thin gauge of the wire is the issue here.
Thanks smokehill, I appreciate the answer. I think you are substantially correct, and I've been assuming pretty much what you said. I've since learned that the reason for steel or iron in cement is that cement is very resistant to compression, while it only weakly resists flexion, tension and torsion. The metal re-(inforcing) bar and chicken wire help to resist tensile forces, while torque and flex are resisted by the combined structure of the tied/wired framework of metal. The combination of the cement mass and the armature (the tied wire/rebar structure) gives even more strength than either material by itself. So depending on the stresses which will affect the finished project, the armature becomes more -- or less -- crucial. On the steps I'm building, rusty rebar should do just fine, the main load is going to be people walking on it (compressive forces) and we don't live in an area where frost or freezing will likely have a significant impact. Thanks again for trying to help, smokehill. Much appreciated.
I have first hand experience helping to build a 73 foot motor-sailer. 1/2" hardware cloth made of pre-galvanized steel wire was used - meaning that the wires were not welded where they crossed to eliminate the need to cut out pieces for fitting curves. We laid up 11 layers. The advantage of a boat over a house is that a boat can take you places and can provide a living. We planned dive charters in the Caribbean. Ferrocement houses can be free-formed with just chicken wire if enough layers are used. The Japanese build ferrocement boats all of the time using wood forms and chicken wire. Damage from things like hitting a reef are very localized and will seep from damage that would knock a hole in a wooden boat. Most ferrocement housing projects, however, are done to provide the interior layer for a geodesic shell that can be covered with a thick layer of polyurethane foam. Some builders even do the exterior polyurethane shell first and then come inside to tack the wire followed by application of the cement.
Wow -- Ferrocement has fascinated me since I read those old Mother Earth catalog articles. When I was stationed in Turkey in '72, I saw several rural motels and small housing projects that seemed to be basically ferrocement domes, but my Turkish wasn't good enough to get a clear explanation of how they did it. I've always wanted to do a ferrocement project, but never seem to do it. I had a plan for enclosing our 50-dog kennel with a ferrocement dome, but wound up cutting back to 25 rescue dogs and gradually moving them into the house & an attached bldg to make the upkeep easier, and free up a bunch of chainlink panels to make dog runs next to the house. We still need a few doghouses in the adjacent yards, so I may try this idea on a small scale. Any thoughts for basic insulation that a dog can't chew? I thought about using that expanding spray foam, but I suspect the dogs would regard it as entertainment instead. I suppose I could make a dome, cover it with the spray foam, and then do another ferrocement dome over that ... but it seems like a lot of work, and a REALLY heavy doghouse to move around occasionally.
put it on rollers
I wonder if a similar idea would work to make a storm shelter? Dig a hole, line with mesh in this manner, then line with concrete and build a roof in the same way. Hmm...
Here are a few positive and informative articles about the "green" dynamics of concrete building by the Portland Cement Association

http://cementamericas.com/mag/pca-honor-green-efforts/

When I say "green" I also mean resource efficient. :)

http://cementamericas.com/mag/cement_cement_concrete_environment/index.html

Have a good one. :)
fishcatcher8 years ago
i like it but 1 problem does it melt in the summer?
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