Dear Folks, Does anyone have any opinions/experience building with Rastra? It sounds really great. I've copied/excerpted some text below from various websites. Molly RASTRA is a concrete form system made of a lightweight material Thastyron which provides a permanent formwork for a grid of reinforced concrete to form load-bearing walls, shear walls, stem walls, lintels, retaining walls, foundations, and other components of a building. 85% of its volume is recycled material - postconsumer polystyrene waste. Beneficial properities include: No toxic outgassing; non-toxic or low-toxic additives. breathes like a house made of natural materials Makes thick, adobe-like walls. Can be easily molded or cut into desired shapes. Easy to make curved walls. Construction does not require high skill level (similar process to strawbales). Basement walls and Stem Walls can be built in less than half the time it takes to form, reinforce, brace, pour, strip, and insulate a conventional concrete block wall. Does not require wood framing (wood is enormously expensive these days) Very strong--superior wind, earthquake resistance; load capacity can be adapted to any requirement. strong pest resistance mold-unfriendly good soundproofing and acoustics 4 hour class A fire rating good insulation value (I think, due to thick walls. It might need to be lightly supplemented for Ithaca; not sure) Can be quickly finished with a single coat of stucco - no mesh or lathing is required. OK with building codes; local examples of large buidings exist if needed.