Understanding Wood Moisture Content

Wood moisture content (MC) refers to the amount of water present in the wood, expressed as a percentage of its oven-dry weight. Controlling wood MC is crucial for successful painting, as excessive moisture can lead to peeling, blistering, and other paint defects.

Ideal Wood Moisture Content for Painting

The optimal wood MC for painting varies depending on the wood species and environmental conditions. However, it is generally recommended that the wood MC should be:

– Between 8-12% for most interior applications
– Below 12% for exterior applications

Moisture Mapping for Optimal Results

Moisture mapping involves using a moisture meter to measure the MC of wood at different locations to ensure it meets the recommended levels. This process helps identify areas with excessive moisture that may require additional drying or moisture barriers to prevent paint problems.

Consequences of Exceeding Ideal Moisture Content

When wood has a high MC, it can absorb moisture from the paint, causing it to swell and eventually blister or peel. Additionally, excessive moisture trapped within the wood can create a breeding ground for mold and mildew, further damaging the paint and the wood itself.