How to Build with Papercrete
People who are truly earth conscious tend to live off the grid. They make every effort to conserve energy, make less impact on the earth, and use materials that are both readily available and sustainable in their building projects. No discussion on earth friendly buildings would be complete without talking about papercrete and how it is used to build homes. This article focuses on papercrete and how it is used, plus some of the advantages of a papercrete home.
What Is Papercrete?
Papercrete is made from recycled paper with a small amount of cement and sand added. The ratio is 60/20/20. The paper/concrete/sand mixture is stirred in a large barrel, much like a blender, until all paper is shredded and evenly mixed with the concrete and sand. Papercrete can be mortared, drilled, hammered, nailed, used as plaster and as an infill between poles or studs. Recently, some people made the mixture without cement, and created Fidobe or Paper Adobe. These products are dense building logs used in construction.
While researching, I found a gentleman that had made a mixer out of an old 55 gallon drum, which was mounted on an old car axle. A unique gearing system attached to an old lawn mower blade did the mixing. He would hook this contraption behind his car, take a slow drive around the block, and have perfect papercrete.
How Is It Applied?
Papercrete is handled much like adobe. It can be made in smaller bricks or can be used much as cement is, and poured into a monolithic wall. If papercrete is poured in a monolithic wall, the density on the bottom will be much greater than on the top. The papercrete will be cut off from the air, causing drying issues. This can cause pockets, creases and voids in the wall. Papercrete will also shrink 30% in height when drying. It stands to reason that building using the slip form method is the safest bet.
One method of construction is the wattle and daub technique. In this construction, a wall is woven using poles and reeds, and then the papercrete is applied. This method has been in buildings dating back to primitive times.
Another technique used is the slipform method. In this method, the papercrete is poured into the forms creating the exterior walls. Forms are placed one on top of the other until the correct height is reached. The papercrete slurry is used to fill joints and reinforce the blocks. This type of construction is very strong, and is used in high rise buildings, silos, and multi-story buildings. Using this technique for building a papercrete house is a good choice.
Papercrete has the disadvantage of not being waterproof, and extra care must be taken during construction to insure that the site is completely waterproof on the exterior. The exterior can be finished with one layer (1/2") of homemade stucco, the mix being Portland cement, slick lime, masonry sand, and water. Be sure to apply evenly, and take great care to ensure that the exterior is completely waterproof. The walls can then be painted with latex paint, using several coats.
The interior can be treated in the same manner. Environmentalists try to build these constructions using the least amount of wood possible. Interior papercrete walls are often painted just as the exterior walls are - with latex paint. A white lime wash, which is very nice looking, can be applied to the interior.
Flooring can be made from adobe, or a mixture of adobe and papercrete. Often, papercrete is used as a subflooring, thus making a good thermal barrier. Flagstones are also often used for flooring. Papercrete, unless mixed with greater proportions of cement, must be covered with another material because papercrete flooring by itself will be indented by heavy tables and chairs.
The Advantages of A Papercrete Home
So far, there has not been a lot of testing done on papercrete home. Because of its greater R factor and insulating qualities, papercrete homes use less energy. Smaller furnaces and air conditioning units can be used. You can use solar power systems in your home if you want to stay further off the grid.
Papercrete has a tendency to absorb water, either through condensation or as an actual liquid. It is imperative that the papercrete home be well sealed, and that it is inspected frequently for any sign of leakage.
The cost of building a papercrete home as compared to a regular stick build is much less. Paper can be obtained easily. The only expense is for concrete and sand. Consider a papercrete house in you next attempt to live off the grid.