Download PDF version (175k) Log In or Register to view the full article as a PDF document.
Q.We're seeing more mold and mildew on framing lumber (or maybe we're just noticing it more, with all the recent attention to mold). Should we try to remove this before we insulate and put up drywall? How? Or is it safe to assume that it won't be a problem in the future because the inside of the house will be dry?

A.Kevin Powell responds: The answer may depend on the perceptions of your customers. While it's a fact that mold will not grow once the materials dry out, you might want to consider other factors: Are the homeowners sensitive to the mold issue? Does your site get frequent visits from prospective customers? Is the moldy lumber being used where it might be rewetted, like an exterior wall in a bathroom?

If so, it might be a good idea either to not install the moldy lumber, or to clean any installed framing that has molded before close-in.

APA ­ The Engineered Wood Association recommends using either a commercial mold-mildew remover or a household bleach solution, while the EPA recommends the use of a detergent-and-water solution. Do the cleaning in a well-ventilated area and never combine bleach with ammonia.

A builder should have a mold protocol in place in order to consistently handle situations as they arise. The protocol should focus on mold prevention, which is typically less costly than remediation in both money and reputation. Inspect material deliveries for mold; establish an agreement with your suppliers that specifies how long you have to inspect a shipment and what steps will be taken if you choose to reject materials due to mold. Time deliveries so that moisture-sensitive materials can be stored in the dry. If materials can't be used right away, make sure they can be protected from the weather. This may seem like an obvious practice, but given the public's heightened awareness and sensitivity to mold, it's worth reviewing your storage practices.

Framing can endure a reasonable amount of wetting, but make sure you allow enough time for it to dry out before closing in. If some mold growth has occurred, try explaining to your clients that it will not compromise the structural integrity of the framing. Hopefully they will understand, but if they insist, you may have to clean off the mold.

Kevin Powell is a research analyst and wood products specialist at the NAHB Research Center.