Soil-Based Monolithic Walls(Pise, Rammed Earth, Cob)

Soil based monolithic walls are not technologically advanced and require no more materials than an OVE wood framed house would. They use soil, Portland cement, some rebar for reinforcing, and sand while an OVE wall uses lumber and nails. The costs would be relatively close here with the exception of a few other pieces of equipment needed for the soil based walls. This equipment would be the forms, compactors, and dirt lift. Together these would probably rent for around $1,500 a day. The only other cost would be training the employees on how to build this kind of structure. I estimate that that would cost around $400-500 per employee to take a class and become skilled enough to be certified and confident. These costs, although seemingly little, add up once the number of employees rise. One must also think that a contractor would not want to build a government project with little or no experience in the industry. In the case of a soil based monolithic wall, a sub-contractor would be a better alternative. The subcontractor may be more expensive, but they will probably be faster, more experienced, qualified, and insured which means that the contractor can blame them if something goes wrong.  Since it is a government building, the contractor should want everything done right the first time to minimize problems in the future. A sub-contractor is a must in this case.

Rammed Earth and Pise walls are made from approximately 30% clay and 70% sand with a small amount of Portland cement.  All of these materials are readily available almost anywhere in the United States and are relatively inexpensive to purchase.

After geological testing is performed on the site, it will be known whether the clay excavated from the site can be used in the rammed earth, pise, and cob walls.

Since the products that go into rammed earth and pise walls are simply clay, sand, and Portland cement, all products can easily be transported to the jobsite.  If the clay is not reused from the project site, Lowe's Home Improvement stated that clay could be delivered to the project site within two to three days.  Sand could be delivered to the project site within two to three days as well from Lowe's.  Lowe's orders their Portland Cement through Quikrete, and stated that dependent upon the exact amount needed for the project site, it could take up to four days to get the cement to Lowe's in Radford, which could then be easily delivered to the project site.  Lowe's assured that there would be no difficulties delivering the necessary building materials to the project site in a timely manner.  The lead time for this rammed earth or pise is at most four days.

Cob walls are constructed of clay, sand, and straw.  Again, the clay can be used from the project site if the clay meets the specifications for clay necessary for the walls, and if not, clay can be delivered to the project site within two to three days.  Sand can also be delivered within three days.  The lead time for straw can be up to seven days, which is the maximum lead time for straw in the Southwest region of Virginia.  However, straw could be available for delivery within two days.

There are currently no constraints on the delivery of the materials needed for construction of rammed earth, pise, or cob walls.  The biggest factor of delivery is calculating exactly how much clay, sand, Portland cement, and/or straw is needed for an 1,800 square foot building.  No matter the quantity necessary, Lowe's Home Improvement in Radford, VA assured me that within four days the quantities of clay, sand, and Portland cement could be delivered to the project site.