Re: Sub-floor options
I do understand about the "wet" issues in the northwest. However, if you are planning on using polyethylene sheets through out the entire process, I would think that they would be awefully hard to paint. I know how much wood I have used so far in my conversion, and to multiply the cost of it versus the sheeting by 12 to 13 times. WOW, that is an expensive bus conversion. Now, not saying that it wouldnt have special uses inside the bus. Like around the shower, sink, toilet areas. Or anywhere else it would be wet, polyethylene would be a good choice.
From what I know about polyethylene, is that it is used in the tubing for radiant floor/ceiling installations because of its ability to give off heat. If you are wanting something to insulate you from the cold coming from the floor, I would (did) 30# roofing paper for moisture barrier, 1" think blue polystyrene board, covered with 3/4" tongue and groove plywood.. Otherwise I think you will be cold with polyethylene as a part of your floor.
95 IH 72 passenger transit school bus w/ DT466 and 545 Allison.
79 IH Scout II/392 (0.030 over) Hamilton Injected/727/D300/Full size axles/36" Swampers/Lockers/OBA/38 gal Custom fuel tank, roll bar, tube doors.