Charlie: Dub in Nederland writes to us. He says, “I’ve been hearing a lot about moisture issues in beach houses subflooring down at Crystal, and new post-Ike builds, and what’s the best insulation system for flooring material in those houses?”
Tom: You know what? If I had my druthers, and they won’t let you do this if you’re gonna follow the new energy codes, and you usually have to when you get the permits, I wouldn’t insulate the floor at all. I had a beach house down there that was built in 1960. It’s still there today. It has no insulation in the floor whatsoever, and it stays bone dry all the time. You don’t have any heat gain coming up from the bottom of the house. It’s always gonna be through the attic is your big heat gains problem.
What I used to do in homes that we would build down there, it was formaldehyde-free fiberglass. That’s the best one to use because it’s not real porous and it won’t hold a lot of humidity and it’ll breathe real well. And use unfaced. No plastics, no vapor barriers. Just unfaced, formaldehyde-free fiberglass.