A Rotting
Timber Frame
Foam sheathing, too much moisture, and
a broken vapor barrier almost spelled disaster
for a four-year-old timber-frame house in
southern Vermont.
by Steven Bliss
"If you don't put in a vapor barrier,
your house is going to rot away."
You've heard this many times, but it's
not so simple.
Thousands of insulated houses with
no vapor barrier (or a lousy vapor barrier
such as kraft paper) have not rotted
away. Furthermore, sticking a sheet of
poly in the wall is no guarantee against
problems. Take the rotting timberframe
house that I visited in southern
Vermont last November...
The 1,800-square-foot, 1-1/2-story
Cape is four years old. The walls are
framed with 8x8 timbers, which are
exposed on the interior