The forty foot diameter of the home gives a square footage of 1,200. The interior space feels much larger because the entire space is open and you can see forty feet to the opposite wall from many spots inside the house. Its only the round rooms which have doors- the rest is one big open room.
The diameters of the round rooms were based upon the dimensions of available steel tanks. The tanks I used for the main entry and bathroom each cost $200 from a local property owner. I had no idea he’d want that little for them, as I had been thinking of using steel cargo containers to build with but the cost for them delivered in my area was about three thousand dollars each- I saw these round tanks behind a local mechanic shop and asked if he wanted to sell them. I borrowed a friend’s flat bed trailer and hauled the tanks with my ’69 Chevy bread truck- photos below.
Below you can see a chain leading away from the left side of the photo, which is attached to the bumper of another vehicle in order to hold the tank in place while the trailer is driven away from underneath it.
I stopped at a local well driller’s home and inquired about him using his crane to set the tanks upright on my concrete pads- he said, ‘let’s do it right now’ and charged me fifty dollars. Below is a photo of his vintage boom truck which he used to hoist the rusty towers into place.
Below is a picture of the 1946 Chevy Panel Truck which is seen to the right of the rusty towers in the photo above. It is a permanent resident, traded from a friend for several framed photographs of old trucks.
Below: the formwork and rebar for two of the supporting concrete slabs, with plant guard fabric beneath.
Admittedly, the above photo does show some barren looking landscape, but here the winter is the dry season when all the plants and grasses die back, and the area had recently been cleared by a bulldozer.
I found another two used tanks which I had delivered from Tucson (100 miles away) which cost significantly more than the first two, but the cost for both with delivery was still less than for a single cargo container, plus being twelve feet high allowed for a high ceiling which was preferable to the somewhat claustrophobic space inside of a cargo container.
Above is the layout of the tanks which become rooms inside the house. The fence in this photo is T posts and galvanized stock panels, laid out in a forty foot circle which is even with the outer walls of the tanks. The height of the floor will be two feet above grade (meaning above the surrounding ground level). This is why there is a black stripe of asphalt emulsion around the bottom two feet of the rusty tanks- because they will be underground- the other two tanks have since been treated similarly. A ferrocement (cement and steel) perimeter will be the base of the wall which anchors into the ground via the T posts. The wall instead of resting on the foundation, is the foundation. I realize this will irk a lot of folks but it works- as the Greek philosopher Antisthenes said, “The most useful piece of learning for the uses of life, is to unlearn what is untrue.” More to the point, the traditional methods of house construction work well within the scope of traditional building materials and practices. What I’m doing is basically building a monolithic (one piece) shell of the house- the walls and roof are a continuous thin sheath of steel-reinforced flexural masonry. In earthbag and strawbale construction, piles of rock are often used as a foundation instead of concrete. Concrete is subject to cracking and frost heave in freezing weather because it holds moisture, unless you use inexpensive additives which almost nobody does because its another step, and another expense. Rocks mortared in place with lime do not suffer this modern problem.
Below, twelve foot tall galvanized steel studs frame window openings. The assemblies were built flat on the ground and tilted into place.
Below, the steel framing begins to better delineate the shape of the house. To the right, the large framed opening will ultimately be a door leading into the kitchen from outside.
Below is a stack of roof trusses made from steel studs, steel track, and corrugated tin sandwiching the studs and track. One ‘leg’ of each truss is longer, as it will rest atop the center tank from which the trusses will radiate outward in a circle. The corrugated tin is staggered face-to-face instead of running in a continuous sheath along both faces of the steel ‘rafters’, so that air can flow within the plenum chamber or ‘vented attic space’ above the ceiling and below the roof.
(Below) My friend Charlie built this crane from scrap pipe and rebar. The boom arm and electric hoist from my 1947 International truck were also used in building the roof truss crane, which pivots on a large pipe nipple in the center of the steel tank at the middle of the house. I lost a bet with him that I could build the entire round house by myself while he toiled at manufacturing the rebar trusses for the sandbag structure. I lost in large part due to not being able to hoist the trusses into place with a rope, a pulley, and a ladder. Oh well.
(Above) The dark cement ring at the base of the building is a mixture of cement and sand worked through a matrix of vertical steel studs, T posts, two bands of 1/2″ rebar completing full circles, and a layer of expanded metal lath on the inside and outside faces which was all sutured together with staples made of baling wire, prior to being cemented. I added ‘Antihydro NC’ to the cement, which makes the cement waterproof as well as making it non corrosive to steel. Ferrocement and reinforced concrete without this sort of additive, has a design life of approximately fifty years. When cement is made with this product, it is FDA approved as ‘food grade’ for building ferrocement water cisterns.
Above, the stock panels are draped with burlap-crete (see the burlap-crete explained page for details.) Advantages of burlap-crete instead of plywood sheathing: cost. Also, it doesn’t warp, swell, delaminate, mold, burn, get chewed through by rodents. Its as strong as half inch plywood, requires no carpentry tools or carpentry skills, and can weather years (nearly ten years so far) in direct contact with mother nature with no noticeable adverse effects. In my climate, plywood left out to face the elements would warp and become sun rotted, possibly mold on the dark interior side, could easily be set on fire, etc. And a lot of plywood offgasses formaldehyde toward the living space.
The roof is covered by overlapping stock panels which are lashed to the conduit using rebar ties. The stock panels are covered with expanded metal lath which is attached using a pneumatic hog ring gun. Using this gun enabled us to attach the entire roof’s worth of expanded metal lath in a day and a half, instead of weeks which is how long it took in order to attach the lath to the roof of the sandbag structure, when using hand formed bailing wire ‘staples’ twisted into place using spring loaded pliers.
Below- windows and door openings are trimmed with expanded metal lath and then will be grouted. (The grout and burlap-crete where left in contact with each other for more than a year have shown no compatability issues.) Also below, note the fresh dirt. Instead of hiring a backhoe operator to dig up the local adobe soil for landscaping and backfilling the house to the height of two feet, I asked the county workers who were clearing washes along the road a mile from the building site, if instead of hauling the dirt they were removing to a dump miles away, if perhaps they’d like a closer location to dump it. They had me sign a document allowing them to deliver the silt to my land and brought over about a dozen ten-ton dump truck loads over the next two days, and we backfilled the house using shovels and wheeled carts, which was labor intensive but free.
(Below) Inside unfinished house, after roof has been coated with grout and walls draped with burlapcrete. To completely trap the steel framework of the walls, a lime based render was at first considered but has been covered with another layer of wire and covered with modified cement. The earthen floor will be covered likely with brick mortared with sand so that the floor can be installed piecemeal (like the rest of the building). I’m planning to spread a thin layer of type S lime over the tamped earth floor, then sand, then brick. The lime will prevent moisture problems and kill mold and bacteria from affecting the living space if the ground beneath should ever become damp.
Chris and Liz who helped on various parts of the building projects and lived on the property during much of the process. Oh, and one of those Arizona sunsets.
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