Cealy writes from Brighton, Illinois: "We have an unfinished basement and want to insulate the ceiling of it. The floor is dirt and tends to get wet when it rains. I saw in another e-mail your answer was to treat it like a crawl space and put plastic on the floor. Since we use the area for storage and the washer and dryer are down there I don't want to have little bits of insulation floating down onto everything. Can I put a sheet of plastic over the insulation I put in the basement ceiling? Wouldn't this have the same effect as putting it down on the floor? Do you have any other suggestions? Or is there any other type of insulation material that might work better?"

Answer: We recommend putting plastic on the dirt floor of a crawl space to prevent moisture from coming up into the space from the ground. Putting plastic on the ceiling will obviously not do that. Also, putting plastic under the basement ceiling insulation may trap moisture that comes from the living space above. If you want to cover the insulation in the ceiling, we recommend using something breathable like plywood or sheetrock.