Tom writes from Minneapolis, Minnesota: "I have a screened porch on a cabin in Northern Wisconsin that we will be converting into 2 bedrooms. Right now, the porch is raised about 1.5 feet off the ground, with 2x8 joists, no current insulation.

We are curious as to how to insulate the floor, without spending too much time crawling underneath to porch. Concerns: Rodents, warmth, sound, moisture, costs.

Ideas: Since there is a cheap thin floor on the joints, we were thinking that we could just rip up the floor, and put insulation in from the top. We would do this by nailing furring strips on the joists, and then lay plywood (Which we have plenty of scraps of) on the furring strips, then lay down the insulation on top of that. We were thinking we may need to prime and paint the 'suspension' plywood for moisture and rot. Is this necessary?

Do you think this system will work? What type of insulation should we use? It will be seasonal use. Perhaps heated a few weekends in winter. But since there will be two bedrooms, we are looking on cutting down the noise too. Please, give me your thoughts!"

Answer: I asked one of my friends at Owens Corning to review your note and he did not see any problems with the assembly you have proposed. You should use Kraft-faced insulation with the paper facing up. The only additional thing you may want to consider is installing some small screened vents in the band joist so there is ventilation.