Wilcox remains a distributor in California for the time being. Yet another company, Rastra Technologies, handles engineering and technical development. Rastra of the Americas and Rastra Technologies. In an encouraging move, Rastra officials have backed away from previous claims that the wall system achieved an R-36 thermal performance. Rastra has contracted with Oak Ridge National Laboratory to document this benefit, and results of their simulations should be available soon.
Rastra walls are also very airtight, which further enhances energy performance.
A proprietary additive helps with the mixing process. This efficiency, together with the use of recycled EPS, makes Rastra environmentally attractive. Functionally, Rastra has a big advantage over most other foam form systems in that the cement prevents insect infestations. Although insects don't eat polystyrene, they often nest in it and can be hard to remove. A modified, half-width version of each panel is used for corners and at rough openings.