Notebook...
JUNE JLC 1997
Consider a typical wooden wall assembly: A 2x4
or 2x6 stud wall, sheathed with plywood or
OSB; fiberglass batt insulation and a poly vapor
barrier; housewrap or felt paper over the sheathing,
with wood siding nailed over that; and paint or stain
on the siding.
Should be fine, right? The poly protects the wall
from interior moisture, the painted siding sheds most
rain and blocks most wind, and the housewrap keeps
the remaining wind and water out while letting vapor
escape.
But in fact, this wall assembly can fail dramatically
under severe exposures, according to Joe Lstiburek of
Building Science Corporation in Westford, Mass., and
Paul Fisette, director of the Building Materials
Technology