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Timber framing with green Larch

Started by foresterstan, June 09, 2015, 06:39:28 AM

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foresterstan

Does anyone have input on timber  framing with green Larch?
or is it better to use dried stock?

beenthere

Prolly always better to used dried stock as far as any potential warp-from-drying goes, but that doesn't mean that using green larch timbers shouldn't happen.
Likely most warp will be a result of growth stresses in the logs and how the timbers are sawn from the logs (pith location), that can be enhanced as the wood dries.
Starting with good straight trees helps too.
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

foresterstan

hey thanks,
I just got a request to kiln dry some 6x6 and 8x8 for an outdoor timber framing project.  the user had no idea on how dry it should be if at all.
rather wary of the long drying times
(BTW, I'm new on this site and very impressed on the activity and content of answers... )

Dave Shepard

Timber framing should be done with green wood. Unless you have an rf kiln, you aren't going to do much drying of stock that thick. If you do use dried timber, it would have to be planed, or you would have to line the timbers as they won't be square, and the faces will be crowned.
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foresterstan

ok, so I just cut the timber 3 weeks ago.  should they use it like it is or air-dry for some time?

Dave Shepard

Personally, I start framing immediately, although letting the surface dry for a few days is nice so your pencil will work.
Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"LogRite!

foresterstan

thanks dave, I will pass that on. 
they had someone give them "dried" timber that was in a kiln for 10 days that resulted in a lot of warping etc. 

beenthere

foresterstan
What is your background, and are you a forester?
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

S.Hyland

Hi Stan,
   I do a lot of timber framing with Larch. It's probably my single most used wood. It has properties pretty similar to comparable Doug Fir; high strength and great color, with fairly high shrinkage and a tendency to twist.
   There are things that help this out quite a bit.
Winter cut timbers are preferable, they are noticeably more stable.
As has already been mentioned, starting out with good quality straight logs is a must, if they are remain straight. 
As Dave said, they should be worked green, and then all end grain should be coated with something like Anchor Seal.
Keep them out of the sun!! You want them to dry slowly and evenly. 
Joinery should be designed to control tendency to twist. Housings help.
In the end, if twisting is entirely unacceptable, don't use Larch.  What they want is White Pine.


The kiln drying is ,in my opinion, a waste of time and money. The moisture content in anything past the first inch is not going to change that much. And if they were left in there long enough to really dry them out they would do all there moving, twisting, etc. without being restrained by the joinery.

Larch is a great wood that is good to work with, and has decent natural rot resistance, but it has it's limitations just like any other wood. If I were you I would explain to your customer that it just has a tendency to twist, which may or may not be unavoidable. That way they can't hold you responsible.
"It may be that when we no longer know which way to go that we have come to our real journey. The mind that is not baffled is not employed. The impeded stream is the one that sings."
― Wendell Berry

foresterstan

 
Quote from: S.Hyland on June 09, 2015, 09:05:10 PM

"Larch is a great wood that is good to work with, and has decent natural rot resistance, but it has it's limitations just like any other wood. If I were you I would explain to your customer that it just has a tendency to twist, which may or may not be unavoidable. That way they can't hold you responsible. "


thanks S.  that seems to be a good way forward...
also good heads up on the anchor seal...

appreciate the help from all. 

Beenthere: my background is a lot of firewood cutting, tree climbing and wildlife/land management, but am really new to this site,  timber milling and drying etc...
(apologies for the non-sponsor shoutout...)

later

-fs

Chilterns

There is quite a comprehensive account of the difference between hewing green and dry larch on the Oxfordshire Woodland group web forum.

Larch has qualities that exceed other trees in that it does not have knot whorls where all of the branches are located at the same elevation around the tree (like EWP / DF) instead it tends to throw out it's branches in a helical manner up the trunk thereby reducing the incidence of localised defects at any position along the log making larch a timber that is  emminently suitable for use in demanding structural applications.

Chilterns

Satamax

Chilterns, you said it, even the wood tends to grow helical too!  ;D


I might have zilions cubic meters of that tree around me. We work with it all the time.   One thing, never ever use a tree which has twisted counterclockwise. And i don't know if it's a good practice, but some guys make a deep saw cut on one side , down to the pith, in big posts, and hide it after. Yep it twists. one good thing is to look at the bark. You can see if the tree is twisted by it's bark.
French CD4 sawmill. Latil TL 73. Self moving hydraulic crane. Iveco daily 4x4 lwb dead as of 06/2020. Replaced by a Brimont TL80 CSA.

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