Howdy everyone. What are y'all's thoughts on spruce wood in timber framing? Up here in PEI we've got mostly just red/white spruce, with some birch, aspen, and maple mixed in. Some tamarack and juniper up east. Spruce is the most available, but it seems like the poor man's white pine or douglas fir :)
Also, what's the general consensus on green vs. dry, especially in the context of spruce? Is it better to let the logs dry or cut them immediately? And is it good to let the timbers dry too?
Cut logs green, air dry timbers on stickers, then sort out the bad actors. Maybe cut oversize and then straighten if needed on the sawmill.
Spruce wood kept dry will last, but build with strength values and structural grades for spruce in mind. It ain't white pine or Doug fir.
Spruce will get some nasty drying checks in it. I have an 8x8 post in our house that developed a 1" wide check. Not a big deal if you don't mind that look.
I've cut a lot of spruce off my land, and as BB said you can get face checks in posts and beams. It varies in each piece how big the cracks get. You also may have to skim cut/plane the faces flat after it dries, I've used 6x6 for pole shed framing and noted this when nailing horizontal boards to them. As usual when logging the butt log and the next log up are usually best grade, the higher up the tree and more clusters of knots the weaker it gets.
This is the post I referenced earlier, witht the large check in the face.
If you have the time saw over size and let dry then re-saw to final size and sort out the ones with too much twisting.
If you don't have time saw and cut joints and assemble as soon as you can, keep the sun off of them and design joints so that the ends of the beams are housed to help control twisting.
For strength spruce, pine and fir (not Douglas fir) are often grouped together, the times I have disassembled stick framing spruce is tougher than pine, knocking a stud sidewise off the nails with a maul the spruce will survive but a white pine will usually break off. Pine often behaves better with twisting than spruce. Fir trees around here (South West Nova Scotia) are sometimes rotten in the middle so often not a option.
There is a beam strength calculator in the tool box on the bottom left below the ads you can do a strength comparison of different woods to see what is what.
I don't think white pine is in the SPF group... hang on.. front of the Supplement.
(https://forestryforum.com/gallery/albums/userpics/10017/speciesGroups.jpg) (https://forestryforum.com/gallery/displayimage.php?pid=353845)
Great advice, thanks everyone!
barbender, that's probably the widest check I've ever seen. :)
Would painting the ends be beneficial after cutting the logs to slow down the drying? Or would that just mean I have to wait longer?
The sorta normal is for all 4 faces to experience some drying checking so it would be spread out. The above looks like it all or most went to one face. How well the pith was centered could (or could not) have been a reason. This clearly illustrates that all logs and the products that they yield are individuals unto themselves.
Personally, I like that wide check and it shows that it is real, not imitation. ffsmiley
Quote from: Don P on May 20, 2024, 05:02:13 PMI don't think white pine is in the SPF group... hang on.. front of the Supplement.
True, Thank you.
The local Potlatch stud mill processes white pine into 2x4's, but only for the pallet market as it can't be mixed with the other species that are getting the SPF grade stamp. That's what one of the mill managers told me anyhow. There's some really pretty white pine that goes through there and gets turned into pallet boards.
I'm guessing their stamp is SPF(S), South?
Anyway, take the checking comment seriously, every species generally behaves in a way. For me Tulip poplar is similar in that all the tangential/radial shrinkage will combine and tend to create one whopper check. Log home companies tried and abandoned it although historic ones are everywhere (Dolly is singing somewhere ffsmiley )... with big checks.
(https://forestryforum.com/gallery/albums/userpics/10017/poplarchk.jpg) (https://forestryforum.com/gallery/displayimage.php?pid=10854)
We did a number with a mix of red and white pine. That was where I first started noticing that red developed many smaller checks and white pine one or two larger ones, but less than poplar.
What initiates the check is a severe moisture gradient between the shell and the core. When tension perp to grain exceeds strength perp to grain (wood's weakest direction) then it splits. If you can moderate surface drying while still allowing the core to dry, you'll reduce the gradient. I would opine to our log home clients that if they would put on some form of oil finish immediately, as a drying coat, it would reduce checking. That first winter, be cold, don't run any more heat than necessary. Moderate surface drying of larger timbers.
With that checked timber above in mind, just another log home observation. My settlement was never close to calculated radial shrinkage. That is an extreme example but notice why. The shrinkage did happen, but the timber checked. It did not lose anywhere near the height that had occurred by shrinkage, much of the dimensional change is in that check.