Moisture content in air dried wood

robliles

Rob
Corporate Member
Ron,
The ultimate moisture content of any wood, i.e. air dried, kiln dried, etc., is going to depend on the temperature and relative humidity of the area the wood is stored. All wood, if stored in a constant temperature and relative humidity will reach the same moisture content eventually. For example, at 70 degrees (F) with a relative humidity of 65%, wood will reach an equilibrium moisture content of 12%. You should be able to find an "Equilibrium Moisture Content (EMC) Chart" on web sites such as the US Forest Products Laboratory. I got mine from Fine Woodworking.

Rob
 

Oka

Casey
Corporate Member
Rob is correct, The range is 7-12% A lot of wood sold is usually 11-14%, the problem is with softer woods - cedar, redwood and woods that are very porous. They can raise and lower based on ambient humidity and or exposure to water. Woods need some moisture in them.

That is why it is important to seal your work once completed so it does not move on you.
 

Willemjm

Willem
Corporate Member
In NC around 12%

Once you place the finished item in a conditioned home, in winter it would go somewhere below 8%.

A finish will not stop the moisture content from changing, just slow it down.

A general design approach is to allow for 1/8” movement across the grain for each 12” of flat sawn lumber.
 

rusty

New User
Rusty
In NC around 12%

Once you place the finished item in a conditioned home, in winter it would go somewhere below 8%.

A finish will not stop the moisture content from changing, just slow it down.

A general design approach is to allow for 1/8” movement across the grain for each 12” of flat sawn lumber.

(A general design approach is to allow for 1/8” movement across the grain for each 12” of flat sawn lumber.)
Does stock thickness have any effect.
I never knew about the 1/8" movement.
What about quatersawn wood?
 

Willemjm

Willem
Corporate Member
(A general design approach is to allow for 1/8” movement across the grain for each 12” of flat sawn lumber.)
Does stock thickness have any effect.
I never knew about the 1/8" movement.
What about quatersawn wood?
Thickness has no effect. Quarter sawn roughly 1/2 of flat sawn.
 

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