Expert: Dave Johnson - 1/4/2009

Question
is there some form of waterproof blow-in insulation i can use under 2x6 decking outdoors(attached to house) before i put in the sub-flooring ? i am enclosing an existing porch with only 3 inches of ground clearance and covered by wire mesh at the bottom thus making rigid or rolled insulation installation impossible. Please help !!!

Answer
Hi Kenny,
No, anything that lays on the ground will absorb too much moisture to be of any value.
If I understand you correctly, your wire is below (or under) the joists, if that is so, put 2" ridgid foam between the floor joists (or more) and seal with spray foam insulation. you might also put a barrier between the joists and the sub-floor.
Don't put fiberglass in the framing, it WILL take on moisture.
Best of luck.

Dave