Moisture Tolerance of Different Wood Species for Framing
Understanding Acceptable Moisture Levels in Wood Framing
Before selecting wood species for framing, it's crucial to consider their moisture tolerance. An acceptable moisture level is generally below the fiber saturation point (FSP), which is roughly 28-30%. When moisture content exceeds this point, wood becomes susceptible to rot, decay, and structural issues.
Moisture Tolerance of Common Wood Species
Different wood species exhibit varying levels of moisture tolerance. Here's a table summarizing their suitability for framing purposes:
| Wood Species |
Moisture Tolerance |
Suitable for Framing |
| Douglas Fir |
High |
Yes |
| Southern Pine |
Moderate |
Yes (with proper protection) |
| Western Hemlock |
Low |
Not suitable |
| Cedar |
Very High |
Yes (excellent durability) |
| Redwood |
Very High |
Yes (excellent durability) |
Selection Considerations
When selecting wood species for framing, consider the following factors:
- Local climate conditions: Areas with high humidity and rainfall require more moisture-tolerant species.
- Protection measures: Southern pine may be used if it's treated or coated with moisture-resistant treatments.
- Structural requirements: Species with higher moisture tolerance tend to be more durable and stronger.
- Cost and availability: The chosen species should balance durability, cost, and availability in your area.
Conclusion
Understanding the moisture tolerance of different wood species is crucial for selecting the most suitable option for framing. By choosing appropriately and considering protection measures, you can ensure the longevity and structural integrity of your building.