basement ceiling insulation thread (hey, why not?)

[davester]

Personally, I wouldn't use sprayed in foam as the primary insulation in the joist bays. I'd only use the handheld aerosols for sealing pass-throughs. It will make it very difficult to access plumbing, wiring, etc. (might not even be legal for covering wiring). Also, I think I'm backtracking on foam panel insulation since it does burn with highly toxic smoke. At my house I used AirKrete, which is a nonflammable foam but is difficult to get. I supplemented it with cotton insulation which is great and easy to work with. However, I'd be leery of the cotton in a basement if there was potential moisture.