Alrighty...I gutted the entire bus, tore out old insulation and am now looking to put the new insulation in. Through reading other threads it seems the spray in foam comes most highly recommended followed by the rigid board. My understanding is that the spray in foam is stand alone.??(meaning no vapor barrier or silver bubble wrap needed) and if I use rigid board, is it recommended to use the silver bubble wrap up against the metal roof, floor, walls. before using the rigid board, and then do I use plastic for a vapor barrier on roof, floor, and walls before I put my final siding, flooring, ceiling on.??Apologies in advance..i don't mean to beat a dead horse..I know this topic is raised a lot...and there are some threads out there...I've just not found the answer for dummies.. I just want to know the order of layers from metal skin to final siding, ceiling ,floors if I use rigid board...Living in full time, 4 seasons.