We’re planning a new post and beam cottage, to be built in the Pacific Northwest – San Juan Islands. Can anyone suggest a length of time for air-drying green timbers, (Doug Fir and Western Red Cedar) before construction?
Can anyone suggest a reference wiht guidelines for seasoning / treatment?
Replies
Timber Frame structures are typically cut and erected green. There are some suppliers now making kiln dried timbers available and also some that offer recycled or salvaged timbers. For more information on timber framing I suggest you check out the Timber Framers Guild website. Excellent place for this type of info. Jeff
The rule of thumb for air-drying green softwood is 1 year per inch of thickness. I live in a similar climate to yours (Oregon Coast) and have found that rule of thumb to be optimistic.
My experience with timber frames (and I've built a few) is that Red Cedar heartwood is pretty stable and the only real advantage to drying it is to reduce weight. If it's only dry in the immediate surface it will readily accept a variety of stains or finishes.
Douglas fir is going to shrink slightly more than the cedar and you'll get more checking. Personally, I think that adds character and it doesn't reduce the strength.
My own house is a mix of logs and timbers and most were put up green. To tell the truth, I enjoyed that first year of pops and bangs and creaks as all that massive wood dried and settled into its comfort zone.
If you're going to be doing the work yourself, as I did, it's a lot more pleasant and easier on your tools to cut mortises, tenons, bore big holes or "slick off" scarf joints on green wood.
If you're wanting "furniture quality" timberframe construction and are willing to spend the bucks, you can have them kiln-dried like Ted Benson does, but on big wood, it takes a long drying schedule and a lot of energy consumption; and patience and deep pockets and a careful craftsman that isn't going to make errors on those now precious pieces.
Good luck
Edited 9/19/2002 4:26:45 PM ET by Notchman