Thanks for the follow up. I am pondering laying down 2 inches of board, and then a final one inch thick coating of spray foam. It seems to cost about the same per inch of thickness.
Originally Posted by "steve.c":3lrxzp43
I have been thinking about closed cell spray foam, thoughts?
First of all I would google spray foam vs rigid and see what you find
Condensation is a big issue for me. Anything other than a spray that adheres directly to the metal surface is going to allow for condensation. This condensation is eventually going to cause your insulation to rot. Not to mention rigid board won't make your bus airtight. There is always some place for air to get through, and if air can enter or escape through an exterior surface the rest of the insulation is pretty much useless.
We spent about $1200 for enough R6.2 closed cell foam to cover the inside of our 40' bus.
It's really messy and really difficult to spray evenly and really difficult to trim, it's a lot more work in general than doing board. But I would do it again in a heartbeat.
Originally Posted by aaronsb
I like the idea of spray foam. I am not so sure about what happens when you have to get back into certain areas that have been foamed.
The answer: I hope you don't have to get back into certain areas that have been foamed.
For me it was half pro, half con-- I wouldn't have been able to hide wires behind the same amount of rigid board. Spraying over wires is easy.[/quote:3lrxzp43]