While creating an earthship wall is simple, earthship floors require much more skill. However, the ingredients are still simple: flagstone, gravel, sands, Portland cement, and water. The flagstone pieces lay on top of a bed of cement about 6 inches thick. So you must keep a constant flow of mixed cement.
Finishing a wood plank floor in an earthship requires even more skill and patience. You need several layers that must be perfectly flat before laying the boards.
This won't be a complete description, only a rehash of observations made while being an intern on an earthship build. Make sure the unfinished floor is as flat as possible before laying out the flagstone. Then lay steel mesh on the ground and cover any areas that will have flagstone. Before applying cement, start in one corner of the floor laying out pieces of flagstone to make then fit together with a consistent 1-2 inch gap between the pieces. You should start in the corner with the least amount of traffic passing through. There will be other projects going on at the same time, so you'll want to minimize the amount of traffic on your flagstone.
Once a 1-2 meter section has been laid out, you can begin mixing and pouring cement for that section. The mix should contain two five gallon buckets of one inch gravel, 1-2 buckets of sand, and one half bag of 92 pound Portland cement. The gravel acts as fill material to reduce the amount of Portland cement needed. Pour the mix over the steel mesh and ground. Brush water on the underside of a piece of flagstone. Lay the piece of flagstone on top of the cement and pound any air pockets from beneath with a mallet. You will see air bubble coming out of the side of the flagstone. Pound until there are no more air bubble. Make sure the piece is perfectly flat with one or two levels. In selecting the next pieces to fit, you'll want to keep them as random as possible. They should be of random size and shape. Avoid rectangular pieces of flagstone. To maintain a consistent gap between pieces on a floor, some pieces may need to be cut with a motorized circular saw.
Sometimes the bottom side of the flagstone piece is not flat. It may have layers that are as much as one inch thick. This excess material should be chipped away with a chisel and hammer. You'll want the surface area of the bottom side of the flagstone to be as flat as possible to eliminate air gaps. The air gaps may give the floor a hollow sound, may cause the flagstone to crack, or may reduce the bond and cause the piece to dislodge from the cement. Also, don't bury the flagstone into the cement. It should rest on top of the cement. Later, you will fill in the spaces between the flagstone pieces with a finer grout material.
Once a section of floor has been laid, let it set overnight and avoid walking on it until the next day. If the section of floor is in a high traffic area for the work crew, you may need to blockade the area with a makeshift obstacle, such as standing up a large piece of foam board. The next day your crew may need to walk on to get to their work locations. So, it should be ready for foot traffic and you can use the space to work on your next section of floor. However, occasionally a piece of flagstone may become separated from the cement. In this case, you can use a cement mix with a higher bonding capability to reapply the flagstone.
Once several sections have been laid out, a couple of your interns can come behind you and fill in the spaces between the flagstone with grout. The grout used in earthships uses the same basic ingredients that have been used all along: Portland cement, water, and sand. It is essentially the same mix that was used to plaster and finish the walls. You'll want to wet the groove and the edges of the flagstone before applying the grout. Fill the crevices to the top surface of the flagstone. Then, with a damp sponge, wipe the top of the grout to make it a rough surface. Later a smooth finishing coat will be applied just as on the walls.
As stated earlier, wood floors in an earthship can be tedious. The foundation of the floor must be perfectly flat, which may take days to complete. The steps are pretty basic: flatten the ground, apply a layer of loose sand, add a layer of foam board, than finish with the wood planks.
Once the sand is perfectly flat, applying a layer of foam board is relatively easy.
The last step is applying the wood planks. The main difficulty with this type of floor in an earthship is that the edges around the floor are not straight. Your earthship walls, no matter how flat you make then, have indentations and protrusions from the tires and other imperfections on the walls. So, unlike a conventional house, where the drywall makes a nice flat edge with the floor, earthship walls are different. As a consequence, much time was spent cutting strange angles in wood to make it fit around the edges of the floor. To make matters worse, wood tends to change shape as it dries out and with changes in atmospheric humidity. So there may be warping or gaps in the wood planks with age. However, this is one example of how you can customize your earthship to your personal preferences.
Tags: Earthships, Alternative Building Materials, Tire Walls, Portland Cement, Recycled Cans, Off-grid Living, Thermal Mass, Greenhouse, Grey Water, Black Water, Ventilation, Cistern, Solar Panels, Rainwater Catchment