A.Steve Thomas, a stucco
industry veteran, responds: I have to admit
(even after a phone call to the builder), this one
has me stumped. There are several possible causes
for the cracking. The prolonged high winds could
have caused the finish to craze, but why on just
one wall plane? The framing lumber could have been
abnormally dry, then "stretched" as it picked up
moisture — but ordinarily the 1/2-inch
plywood should have prevented cracking. Conversely,
the lumber could have been excessively wet, then
shrank as it was protected from the rain. But
again, the plywood sheathing should have restrained
movement enough to prevent cracking. It’s
also possible that the 1/2-inch plywood could have
been butted too tightly, causing it to buckle at
edges and cracking the finish.
Another possibility is that the wind lifted the
roof and wall, or caused the wall to rack (not
uncommon in garage walls because of the large
openings and consequent lack of lateral bracing.) I
asked the builder whether impact loads or heavy
loads in the attic floor could have played a part,
but no such impact occurred, and there’s
no floor in the attic yet, so no loads.
The stucco itself could have been mixed way too
rich (too much Portland cement), which might cause
shrinkage cracks. But again, what are the odds of
this occurring on just one face?
My best advice to the builder is to try to
stiffen the gable end by installing hurricane
straps at the top and bottom of each stud and
installing metal X-bracing on the interior of the
wall. Then I would accept the stucco
contractor’s offer to span the cracks with
mesh tape and refinish the affected wall plane, in
hopes that the resulting color will match the
adjacent walls acceptably. It would probably also
be a good idea to secure the homeowner’s
signature that this attempt on the
contractor’s part is the last free effort
to solve the problem.