Hard to tell for sure without a close look, but the roofing / waterproofing material looks like TPO, a single-ply roofing membrance. It is not made for direct traffic, so appears someone has installe ... read more
Air sealing and insulation are the two biggest things you can do to globally improve the efficiency of the home.
There are several articles on this application and I have yet to be in a home that di ... read more