Nearly 20 years ago, plastic housewrap burst onto the building scene
with the introduction of Dupont's Tyvek. Since that time, Tyvek
and a host of imitators have become standard materials, and are
displacing tar paper in much the same way that plywood displaced
board sheathing. Housewraps were originally marketed
chiefly as air infiltration barriers, but since
these materials are commonly used instead of felt
paper, they are also relied upon as weather barriers. This means that in addition
to preventing outside air from leaking through, the housewrap also has
to keep out any rainwater or snowmelt that finds its way behind the siding.
The plastic wraps are touted for another