Ralph writes from Minneapolis: "I have an attic with 2x6 floor joists and blown in cellulose insulation. There is a finished wood floor on top. The room is used for storage. Can I stack up some rigid foam sheets on top of the wood floor and place a second wood floor on top of the rigid insulation or will I have moisture problems under the rigid foam?"

If you go thick enough on the foam - I recommend PINK FOAMULAR® 250 insulation - and maintain normal indoor relative humidity levels in the home - 40 percent or less in the winter - there shouldn't be an issue. This is, however, not an application we have ever tested so there are no guarantees.