Lignomat moisture meters since 1979. Measuring moisture is our expertise.

Below is the EMC table and chart.

From the US Dept. of Agriculture Wood Handbook, “Wood as an Engineering Material”
Humidity recommendations range from 30% – 50% in a building.
Temperature recommendations range from 60°F – 80°F in a building.
If ambient conditions stay within these recommendations, the moisture content of wood stays between 6% and 9%
and the amount of expansion and contraction of wood is limited.

Examples: (1) Conditions in a warehouse are 60% relative humidity at 50°F.
Dry wood is left in the warehouse for an extended period of time.
The wood will pick up moisture until 11.2% MC is reached, regardless of wood species and initial moisture content.
(2) Lumber at 7.7% will not change its moisture content if kept at 40% relative humidity and 70°F.
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Relative Humidity EMC Table
T °F 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95
30 1.4 2.6 3.7 4.6 5.5 6.3 7.1 7.8 8.7 9.5 10.4 11.3 12.4 13.5 14.9 16.5 18.5 21.0 24.3
40 1.4 2.6 3.7 4.6 5.5 6.3 7.1 7.8 8.7 9.5 10.4 11.3 12.4 13.5 14.9 16.5 18.5 21.0 24.3
50 1.4 2.6 3.6 4.6 5.5 6.3 7.1 7.9 8.7 9.5 10.3 11.2 12.3 13.4 14.8 16.4 18.4 20.9 24.3
60 1.3 2.5 3.6 4.6 5.4 6.2 7.0 7.8 8.6 9.4 10.2 11.1 12.1 13.3 14.6 16.2 18.2 20.7 24.1
70 1.3 2.5 3.5 4.5 5.4 6.2 6.9 7.7 8.5 9.2 10.1 11.0 12.0 13.1 14.4 16.0 17.9 20.5 23.9
80 1.3 2.4 3.5 4.4 5.3 6.1 6.8 7.6 8.3 9.1 9.6 10.8 11.7 12.9 14.2 15.7 17.7 20.2 23.6
90 1.2 2.3 3.4 4.3 5.1 5.9 6.7 7.4 8.1 8.9 9.7 10.5 11.5 12.6 13.9 15.4 17.3 19.8 23.3
100 1.2 2.3 3.3 4.2 5.0 5.8 6.5 7.2 7.9 8.7 9.5 10.3 11.2 12.3 13.6 15.1 17.0 19.5 22.9