1,000 Year Doghouse

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Posted in WorkshopMolds-and-casting

Introduction: 1,000 Year Doghouse

About: EE, retired

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.

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).

Step 3:

Now Frisky will be safe and secure. When Armageddon comes, I'm heading for the doghouse!

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    user

    We have a be nice policy.
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    90 Comments

    user

    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.

    6 replies

    Here is an excellent article on ferrocement

    http://www.engineeringcivil.com/water-proofing-by-ferrocement.html

    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.

    user

    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.  

    Thanks for the LOL, but you missed my point: this is a dog house, not a containment pond or a driveway. It won't leak any more than a clay planter will. Maybe after a few years of freezing and thawing it will have hairline fractures, but this isn't a boat, it's a doghouse. Let's not overcomplicate things, hmm?

    I made a rain barrel from ferrocement; no sealant, no leaks.

    user

    The permeability (an cracking) of the cement/concrete depends on the ratio of the mix and the type of binders/fibers/reinforcement used. Also cements include more than the common Portland type that most people think of. Magnesium oxide based cements are far more moisture resistant *and way more expensive on a per lb. basis.

    If you want to ENSURE impermeability you will want to use the right ratio of the correct ingredients (including and acrylic latex binder) and then paint or coat with a flexible elastomer paint (like the EPDM paint used on RV roofs now). Over kill perhaps, but a good guarantee.

    The cement used in driveways, sidewalks, etc, is only poorly porous, which is why run off from developed areas is an ecological issue. But due to cracking and poor ingredient ratios it also doesn't keep the ground under it dry enough to prevent life forms from living under it...

    I love the FidoDome, DomeHead! You did a great job and the Master looks tail-wagging happy! Depending on what area you live in you could probably get by without sealers. With ferrocement/ferroconcrete and the dome shape the most will happen is rain will slowly absorb and then it will follow the path of least resistance. Downhill around the edge. It would be a rarity for it to leak at the top and as long as you don't have to worry about a wet FidoDome freezing then you could probably bypass sealer, but sealer would be a good thing.

    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.

    1 reply

    Maybe this will help

    https://en.wikipedia.org/wiki/Ferrocement

    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!

    1 reply

    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.

    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.

    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

    3 replies
    user

    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!

    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

    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.