In a previous post about natural building I talked about foundations and building from adobe bricks. Now, that the walls are erected it is time to introduce plastering. Plastering is similar to mortar, but needs to be stickier so cow manure is added. There are three coats of applied altogether. The first plaster mix is made from 15 parts single sifted earth (subsoil), 10 parts sand, 5 cow poop, and a bit of fiber. Although a plumb bob and leveling system is used when laying the bricks, the first plaster is applied liberally in order to create a more level surface. The additon of manure gives the mixture impermeability and stability because of the stomach enzymes and microfibers. Horse manure can be used instead of cow manure but it has fewer enzymes. The manure can be added in the mix either fresh or fermented. We applied the plaster using our hands to spread and smooth and just like laying mortar on bricks, the surface needs to be completely wet. Cracks will develop when it dries but we want that with the first coat. When the second is applied it fills in the cracks and adheres better to the wall. Once the walls are dry check over the areas with your hand and feel if there are loose pieces that need to be replaced with fresh plaster.
The second mixture of plaster is made from 12 parts double sifted earth, 10 sand, and 5 cow manure. This layer and the third do not have pine needles or fiber and have a higher proportion of sand because it makes it more stable and smooth, basically nice looking. It can be applied with both our hands and trowels. We used both methods, however, in seperate rooms to see the difference. Personally I prefer the hand method because I like the imperfection quality it gives.
The third mix is super liquidy and fills in the small cracks left by the second plaster. It is more of a slip layer and it is burnished into the wall using our hands once again. I was actually burnishing so much that I got blisters. Hardcore. So, plastic bags can be worn over your hands so that they are not so worn out like mine. The ration is half sand to half triple sifted earth. In general, plastering is used for protection and aesthetics.
The rooms we were building will be used as a bedrooms so a place for storage was designed into the plan. The great part about earthen building is that furniture can be made not bought. The shelves are built into the wall so when we were laying bricks there were spots that were marked to b left open. The holes would be filled with wood posts so that a wooden plank could be laid across. Bam! a shelf is made. Small shelves can be made with meatballs. Meatballs is a term used to call a mixture of first plaster and a lot of fiber. We shape it into a ball and spread it on the wall in areas that need filling. The fiber is smoothed with the mud and held up from its tensile strength. Window sills were also made this way. Bottles are installed during the building process as a decorative element that allows light to filtrate in. Bricks may need to be adjusted with a machete in order to make room for a bottle.