House wrap is gaining in popularity because of the race to build more energy-efficient homes. If you have looked at many new homes under construction, you likely have seen numerous plastic-looking jackets wrapped around the walls .
Its purpose? Simply to protect the insulation from blowing winds. As soon as moving air is introduced into insulation, its
R value decreases, and energy costs increase.
Building wrap promotes more energy efficiency by permitting moisture, but not wind, to pass through its material. If the seams are well sealed, the effect can be dramatic. Of course, home wrapping is not a necessity if the
exterior sheathing
is tightly caulked and sealed at every opening. However, because it is not terribly expensive, many builders like to use it as insurance against hidden energy losses.
Since the building wrap is not directly exposed to the indoor air, it is generally not considered to be source of serious outgassing.
Some people, however, choose an aluminum foil-faced product instead, often called "builder's foil". If is also referred to as reflective foil insulation as it is used to reflect radiant energy in some cases. It is typically sealed with a special aluminum foil tape. Two brands of foil tape that work well with the chemically sensitive are Polyken as well as a foil tape from Tyco Adhesives.
