Insulation, Radiant and Vapor Barriers - Insulation for 3-season porch floor

Hi -

I am thinking about turning a 3-season porch into a 4-season porch. I can easily get underneath the porch, where all the floor joists are exposed. I would like some advice on how to best insulate the floor - use 6-8 inch thick fiberglass insulation, and cover with some kind of thin plywood just to protect it from the weather, or use Styrofoam insulation, which may or may not be covered. What would be best? If I went with the Styrofoam, do you think the entire depth of the cavity would need to be filled (I guess that would mean having a double or triple layer, since I have only seen it 2 inches thick)? Other than cost, are there advantages of one over the other?

Thanks - Dave

As far as best closed cell spray foam is the best. Your two options are about the same. you will need to cover both with something like ply wood. If you use the foam two layers should be fine.

Hi -

My nephew was just here. He suggested, instead of just insulation, to run radiant floor heating in the porch floor instead. I can get up underneath, possibly run the lines myself (with advice), and have a plumber come in and hook it up to a heating zone we have just in the next room.

How hard is this stuff to deal with?

Dave