Hello, my first post although I've been reading and learning here for some time.
My background is in construction carpentry and joinery. No practical experience with traditional timber framing.
I would like to build the frame in Jack Sobon' Classic Timber-Framed House but I'm having trouble sourcing 8"x10" timbers free of sapwood for plates, girding and tie beams.
I have spoken to some local loggers who can sell Japanese cypress up to 13" diameter with around 2 inches of sapwood. The heartwood is very resistant to bugs and rot, the sapwood less so.
Logs that could produce these beams free of sapwood are fairly rare around here and come with a hefty price tag. Would folks here advise against using this material in plates and beams even in dry positions within the frame?
If they are in the dry then there will be no problem. For sills on stone or concrete try to put a vapor or water barrier down to help protect the sapwood. If you have a timber that has more heart wood on a face and you can put it down/out to the face that will take the weather.
It is just not a problem over there. Even here the trees from which timbers are sawn are getting smaller.
I have the same frame cut in Spruce, it's got plenty of sapwood and wane, no problems.
Unless the sapwood on Japanese cypress is unusually weak you should be fine provided you keep it dry and protected as Arky says.
Thanks for the replies.
Arkansawyer: just what I wanted to hear. I'm still at the sourcing materials stage and the more local the better. For the posts and sills I have in mind hardwood and will need to look further afield.
Raphael: the frame you built and the proportions of the lean-to / ell worked out great. Japanese cypress (sugi) is similar in strength to eastern yellow pine. One concern I have is the different drying stresses of the heartwood / softwood causing severe checking. This may be only aesthetic and I don't mind that at all.
Spring is on it's way here and I hope to be cutting this frame over next winter. The logs are coming off the mountain in march. If I debark then stack logs over summer, milling them just before cutting the frame would I encounter worse movement and checking as they dry in the frame? It sure would make them easier to handle
Should I wait, source the logs closer to the winter frame cutting and gamble that I will still be able to get a good price? I'm thinking the greener the better but it is difficult to pass on the logs coming out now.
tam:
First of all, welcome to the forum.
And debarking is a must if you're going to store these logs.
Also, you need to get them up off the ground or the ground layer will be junk.
Waiting to mill timbers later will give the logs a chance to re-act to the drying process, some.
This maybe a good thing to see where the sweep and other defect may develop.
Be sure to coat the ends with the proper end sealant or they will check badly at the ends.
Jim Rogers
Thanks for the welcome and the advice Jim.
I have the option to use two species of cypress in building this frame. One is "sugi" (Cryptomeria japonica) mentioned above. The other for use in the sill is "hinoki" (Chamaecyparis obtusa).
I would like to hear any opinions on using hinoki for the main posts also. The strengths are below in metric (kgf/cm2) :
Fb 750
Fv 75
Fc 400
And for comparison on the same metric chart douglas fir is listed as being :
Fb 780
Fv 80
Fc 420
Spruce (Picea Jezoensis) :
Fb 720
Fv 75
Fc 360
And American red oak :
Fb 1001
Fv 125
Fc 473