How should moldy lumber in a wall cavity be treated?

The correct approach for treating moldy lumber in a wall cavity is to utilize abrasive methods followed by HEPA vacuuming. This method is effective because it allows for the physical removal of mold growth from the surface of the lumber. Abrasive cleaning can include techniques such as sanding or scraping, which help to dislodge and remove the mold colonies.

After the abrasive cleaning, the use of a HEPA vacuum is crucial because it captures the mold spores and particulate matter that have been disturbed during the cleaning process. This step is important for preventing the spread of mold spores to other areas of the structure or to the indoor air, which could lead to health risks and further contamination.

Alternatives, such as simply replacing the lumber, may not be necessary if the mold can be effectively remediated. Washing with soap and water is generally insufficient for mold removal on porous materials like wood, as it may not fully penetrate the surface to eliminate the organisms. Sealing with a protective coating could help prevent future mold growth but does not address the existing contamination directly, which is why it is not considered a primary treatment method in this case. Therefore, abrasive methods followed by careful vacuuming provide a thorough remediation strategy for moldy lumber.