How fast does a green timber dry?

Hi Grigg.
Assuming that I cut the trees in February. I get them milled right away and sent to a drafty, semi-heated shop where they spend 8-12 weeks. The Sheathing of the frame starts immidiatly after raising, but it takes 2-3 months before the indoor climate becomes indoor climate.
What kind of moisture content can I expect in the timbers by the time the owners move into the house?
I know that there are a million factors to consider, but lets say that I work in green Douglas fir or Norway spruce.
I'm guessing that the most critical frame members in this connection are the girts. They would normally be 8" x 8" or 6" x 8".
Mikkel

You're right, Mikkel. There are a bunch of things to consider.
In your favor, cutting the trees in February while they are dormant will start you with a lower initial moisture content. Softwoods, being less dense than hardwoods also dry more quickly.
However, a total of about 6 months is not long for drying to progress in an 8x8 timber. The outside inch or two will be dryer than when you started, but there will still be a fair amount of water in the center of the timber.
Also affecting the drying rate is the relative humidity and amount of air circulation. Less humidity and more air helps, but too far in that direction leads to case hardening and surface checking.
Probably the best bet is to detail your joinery so that the timber shrinkage is hidden. Housing the ends of the timbers would hide the gap that develops as the recieving timber shrinks.

[This message has been edited by Grigg Mullen (edited 03-01-2000).]

Let me elaborate
As far as I have found out, trees have a moisture content of 23-25% when they grow.
Here in Denmark there are rules that lumber -2"x6" material etc.- must not exceed 18% moisture if you want to use it for building.
I don't know if the same rule applies to timber, but I am trying to be prepared if I run into the question.
Will my softwood timbers have reached a moisture content of 18 % 6 months after milling?
Or: How long does it take for a green timber to dry to 18 % moisturecontent?
Mikkel

Mikkel,

You have exhausted my store of knowledge on the drying time for large timbers. However, Al Anderson at Blue Ridge Timberwrights went through a long process on the subject. The Old Salem covered bridge for the North Carolina Department of Transportation was built from recycled yellow pine. The timbers had been submerged and had to be dried to some required moisture content (I think 12%). Al should be able to give you a feel for what was required.

Hope all is well,

Grigg Mullen

[This message has been edited by Grigg Mullen (edited 03-02-2000).]