Control of Moisture in Wood Framing Assemblies

What is an Acceptable Moisture Level in Wood Framing?

Maintaining proper moisture levels in wood framing assemblies is crucial for structural integrity and longevity. Excessive moisture can lead to decay, mold growth, and structural damage. Conversely, excessively dry wood becomes weaker and more susceptible to damage. Therefore, understanding and controlling moisture levels is paramount.

Acceptable Moisture Content:

  • For interior wood framing, an acceptable moisture content range is between 12% to 15%. This range ensures that the wood is adequately dry to resist decay and mold yet not too dry to lose its structural strength.
  • For exterior wood framing, a slightly higher moisture content range of 15% to 18% is acceptable due to the potential for moisture exposure from the environment.

Moisture Control Techniques:

  • Use Dry Lumber: Start with lumber that has been properly seasoned and dried to the appropriate moisture content.
  • Protect from Exposure: Cover exposed wood framing with moisture-resistant barriers, such as house wraps or roofing underlayment.
  • Provide Ventilation: Ensure adequate ventilation in crawl spaces, attics, and other areas where moisture may accumulate.
  • Inspect Regularly: Regularly inspect wood framing for signs of moisture damage and address any issues promptly.
  • Moisture Meters: Use moisture meters to accurately measure the moisture content of wood framing, ensuring compliance with acceptable levels.