Moisture Map of North America

The numbers on the accompanying moisture map of North America provide examples of how average moisture contents for interior wood products vary from one region to another, and from one season to another within a region. Actual moisture content conditions in any region may differ significantly from these numbers.
Printed with permission from NWFA.

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The EMC chart provides the correlation between moisture contents listed above and ambient relative humidity and temperature. Wood is stable at the given moisture and relative humidity ranges.

Here is an example: For most of the State of Florida the range (without an HVAC unit reducing the humidity) is listed as 12-13% wood moisture.  The 12-13% moisture range is based on an average relative humidity between 65% and 75% for temperature ranges of 40°F to 100°F.

If the relative humidity is higher or lower, the moisture contents will change. Therefore the sentence above the map: Actual moisture content conditions in any region may differ significantly from these numbers. 

The EMC Calculator.com lists values for any relative humidity, temperature and the corresponding stable moisture content. 

Another example would be, someone moving from the coastal areas of California to the high desert of Nevada. Every piece of furniture is acclimated to the coastal conditions with relatively high humidity. Being exposed all of a sudden to very low relative humidity will dry out the wood from the surface towards the core. This alone can result in surface checking. Over time, every part of the furniture will follow and dry out. Glue lines may fail, delamination and other defects will appear. → Read more about shrinking…

Lignomat offers a line of meters to measure moisture and humidity. Measuring moisture and humidity is the first step in avoiding moisture problems. Because if you don’t know, how can you prevent. If you have a question, call Customer Service at 800-227-2105 or go to www.lignomat.com