NC State Extension Publications


Moisture problems in the walls, crawl space or attic can lead to serious pest problems, such as wood-boring beetles and wood-decaying fungi in the floor joists. Mold and mildew growing on wood or insulation can also attract nuisance pests, such as plaster beetles, which can slowly build up in numbers and become a chronic problem. Keep a few important facts in mind:

  • Having mold or mildew on joists or beams does not mean that wood decay will occur.
  • Wood-decaying fungi do not grow below the fiber-saturation point (28 to 30 percent moisture) of the wood.
  • Problems with wood-boring beetles are less likely to occur when the wood’s moisture content is lower than 15 percent. This level may be difficult to reach immediately.
  • Do not seal up walls until the wood moisture content is down to 19 percent or lower.
  • You need a wood moisture meter to determine if you have excess moisture in your crawl space, attic or framing wall.

Your priority should be to complete permanent or temporary repairs and to allow any structural wood to dry out as quickly as possible. It may take some time to get the wood moisture down in the crawl space, but it is not impossible. Here are a few hints:

  • Clean any solid wood surfaces with non-phosphate detergent.
  • Disinfect to kill any mold that the cleaning may have missed.
  • Consider a borate treatment to resist termites, decay and mold. Do this while the wood framing is exposed.
  • After cleaning and disinfecting, air out and dry out the home.
  • Make sure foundation vents open properly and that they are clear of debris.
  • Remove standing water from the crawl space as soon as possible. Increase ventilation to the crawl space. This can be a simple matter of opening the crawl space door or using a fan to pull air OUT of the crawl space, assuming that weather conditions (and availability of electricity) allow you to do so. You may have to use some large-mesh metal screening over the crawl space door to keep out animals, such as raccoons, opossums and skunks.
  • Remove and replace place wet insulation in crawl spaces and walls. For more advice on home repair and moisture control and reduction in storm-damaged areas, contact your county Cooperative Extension center.
  • Remain on mold alert. If mold returns, repeat cleaning and drying process.
  • Do not restore the home until all materials have thoroughly dried.

For More Information

Skip to For More Information

For more information on disaster preparedness and recovery visit the NC Disaster Information Center.

For additional information about mold removal for your flooded home, visit:

Disaster Recovery: Mold Removal Guildelines for Your Flooded Home

Rebuild Healthy Homes: Guide to Post-disaster Restoration for a Safe and Healthy Home

Find more information at the following NC State Extension websites:

Publication date: June 11, 2014
Revised: March 27, 2024

N.C. Cooperative Extension prohibits discrimination and harassment regardless of age, color, disability, family and marital status, gender identity, national origin, political beliefs, race, religion, sex (including pregnancy), sexual orientation and veteran status.