What is an acceptable moisture level in wood framing?
Every wood species has its own threshold of moisture content (MC) tolerance. The acceptable moisture level for wood framing generally varies between 12% and 15%. However, the National Wood Flooring Association (NWFA) recommends adhering to a lower moisture content of around 6% to 9%.
Proper moisture management is critical in wood framing, as excessive moisture levels can lead to several issues. Wood tends to expand when its moisture content increases and contract as it dries out. This phenomenon causes buckling, cupping, and other problems in wood framing.
To ensure optimal performance and longevity of wood framing, it’s essential to regulate moisture levels. By maintaining the appropriate moisture content, the wood’s dimensions and stability can be preserved, reducing the likelihood of structural damage.
The table below provides a general overview of moisture tolerance levels for various wood species:
| Wood Species | Moisture Tolerance (%) |
|---|---|
| Douglas Fir | 11 – 13 |
| Hemlock | 10 – 12 |
| Spruce | 10 – 12 |
| Southern Yellow Pine | 12 – 14 |
| Western Hemlock | 10 – 12 |