Talk:Underground Housing

Regarding the uphill patio: it should be no problem designing a 100% water tight roof. If polyethylene sheets is the chosen material, multiple layers will probably be needed. Another way is to build a ferrocement roof which will last for a long time and can be repaired if it ever does get damaged.

Most underground architects do use cement; Oehler focuses on houses that anyone can build with hand tools and ultra-cheap materials, hence the use of polyethylene.