Jeff writes from Jackman, Maine: "We are building a new house this summer. My building contractor says that my specification that he install 6-mil poly film over the 6" Kraft-faced insulation he will be installing will make the house "too tight," as he puts it. I think it's important to span the potential vapor barrier gap that occurs between studs to make sure moisture from the room does not get out into the insulation and condense on the backside of the exterior plywood. Am I right, or am I going to regret building a house that is "too tight" if I overrule him?"

Answer: In many locations I would say the poly should be avoided. However, in Maine a good vapor retarder on the interior is a good thing. There is no need to use Kraft if you are using plastic. I also think you would be fine with just the Kraft paper. No, you really can't get a house too tight. You do need to be careful that the tighter the house the more attention you need to pay to your HVAC system. You do need to bring in outside air to keep the home fresh. Basically, you want the house to breath but you want to control how it breathes. Your HVAC contractor should be able to help with achieving the proper amount of air changes in the house.