When air is allowed to flow through a building insulation system (i.e., insulation, vapor retarder, adhesive, clips, etc.) the resulting R-value is zero. The air flowing through the insulation usually carries moisture with it, resulting in condensation, mildew, rot, and corrosion. These conditions occur due to a faulty vapor retarder/insulation system design and/or inadequate installation.

In this paper, the author reviews 40 years of consulting on insulation/moisture problems. Insulation systems need to be carefully designed and installed for thermal efficiency.

Units: Dual