Wood moisture content (MC) refers to the amount of water present in the wood fibers. It is critical to determine the MC before painting, as excessive moisture can lead to blistering, peeling, and other paint failures.
Wood MC is typically expressed as a percentage of the oven-dry weight of the wood. The optimal MC for painting varies depending on the wood species, but generally falls within the range of 8-12%.
Moisture mapping is a non-destructive method of measuring moisture distribution in wood. It involves using a specialized moisture meter to take readings at multiple locations on the wood surface.
Moisture mapping can identify areas of high or low moisture, as well as potential moisture sources (e.g., leaks, water damage). This information can guide decisions regarding repairs, moisture mitigation, and painting schedules.
The ideal MC for painting is when the wood is dry enough to prevent paint failure but not so dry that it becomes brittle and susceptible to cracking.
For most wood species, the optimal MC range for painting is as follows:
By measuring MC and using moisture mapping techniques, you can ensure that your painting project is done on properly conditioned wood, resulting in a durable and long-lasting finish.