The spring project is to have our third floor walkup insulated so it can be a conditioned space. It is a century home, has original tongue and groove flooring. The roofline and exterior walls are exposed to I can insulate the best way possible.
My question is this. Can I spray 1" of closed cell foam on the roofline and exterior walls to air and vapor seal, than spray open cell foam in the remainder of the wall cavity? The open cell will provide additional insulation, noise reduction and is much cheaper than trying to spray closed cell to fill the cavities.
I do not have soffit vents, but I will have to seal off the roofline where it crosses over the house frame. I do have three roof vents that need sealed (piece of plywood than foam, or just spray foam it?)
Second question....are IC recessed lighting acceptable to have the spray foam right against it.