- Q.My son's house has been
sitting in 10 feet of water since the levee between
Lake Pontchartrain and the Mississippi River broke
following Hurricane Katrina. He's considering tearing
the two-story home down to the studs. I'm wondering if
wooden studs standing in water for at least 10 days
— and maybe more — are structurally
sound.
A.Paul Fisette, director
of Building Materials and Wood Technology at the
University of Massachusetts Amherst and a JLC
contributing editor, responds: Framing lumber
that has stood in water for 10 days will be
structurally sound once it is dried out —
if it was originally sound. However, swelling and
shrinkage associated with wetting and drying can
compromise the integrity of connections, delaminate
plywood, and cause irreversible swelling of
composites like particleboard and OSB. But as far
as the lumber itself goes, the simple answer is
yes: After drying, wood that was exposed to a
relatively short but extremely wet period should
not lose structural strength. It's important to
reduce the wood moisture content to 15 percent or
lower and keep the wood dry in service to ensure
good performance.
Naturally, there is also a concern about mold.
Affected finishes like drywall should be stripped,
insulation should be removed from the framing
cavities, and all structural lumber should be
exposed. The surfaces of the framing should be
cleaned with bleach and detergent. Bringing the
moisture content down below 15 percent will prevent
new fungal growth and cause any residual mold to go
dormant.
There are, of course, other issues to be
concerned about — pollution of the flood
waters has been widely reported, for example.
Bacterial contamination (such as E. coli) shouldn't
be a problem once everything dries out and all
reachable surfaces (you won't be able to touch any
contamination that has seeped into crevices) are
cleaned appropriately; the bacteria won't survive
for long in a dry environment. Ditto for viral
contamination, though viruses may persist a bit
longer.