Moisture Content (MC)
The percentage of water in wood by weight relative to the oven-dry weight. Lumber graded S-DRY has been dried to 19% MC or less; KD (kiln-dried) is typically 15% or less.
In Detail
Moisture content affects dimensional stability, nail holding, and decay susceptibility. Green lumber (S-GRN) is above 19% MC. Kiln-dried lumber (KD or MC15) is dried to 15% or less. Equilibrium MC for interior use is 6–10%; exterior is 12–18%. Framing should be at or below 19% when enclosed. Use a pin-type moisture meter to verify.