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.
