maillemaker wrote:
I don't understand why the houses are not just made completely from plastic. Large blow-molded or vacuum-formed shell components.
The main reason is referred to as the "UBC" or "Uniform Building Code" known by some as the national bible for building construction. It does not apply (directly) to vehicles since they are not considered buildings.
The fact that most buildings are financed for at least +-30 years motivates most lenders to require that the materials used in construction, at least for the main structure, will outlast the initial loan period.
In other countries I have seen multistory residential buildings built from 2" thick styrofoam panels, covered with chicken wire with 1/2" of shotcrete both sides. The project Architects/Engineers assured me the expected design life was 10 years. The buildings were lucky to make that. You could think of them as recyclable soda bottles or insulated coffee cups.
Chum lee