Emerald ash borer and timberframing
peteshlagor
| Posted in Construction Techniques on
With the ash tree falling like weeds, how’s the dead wood for timberframing?
I see much beetle killed pine being used up here in the mountains, but what about down below there?
Replies
ash has a good strength to weight ratio (think baseball bats), attractive oak-like grain, and is cheap right now as the species is purged from infested areas, resulting in an oversupplied market -
downsides are open grain (needs filled for uses such as flooring), splits easily, and trees that are not straight and symetrical can be 'wangy' (true to some extent with all species, but it's difficult to work bends out of ash because of its strength) - fair to poor rot resistance -
one of my favored woods - early european settlers used it for rafters, joists, and flooring - more mellow and comfortable than oak -
Has anyone heard of recent attempts at timberframing with the stuff?
do you have a specific concern associated with ash?
I googled around, found a timber framing forum with an unanswered question about species of ash and timber framing - and a couple of companies that will be happy to critique your specific situation -
are you thinking about your lake house?
I do know there are many 150+ yo timber framed barns in this area with ash components - it's unusual to see a frame out of a single species since building these structures was a local activity and the mixed hardwoods in the immediate area furnished materials -
observational evidence suggest that ash is entirely appropriate for any application with the exception of sill beams, or other components where moisture/rot resistance is a concern -
aesthetic concerns only you can answer - does a light colored, open grained wood please your eye? -
"there's enough for everyone"
do you have a specific concern associated with ash?
Yes. These mountain pines out here in Colorado are getting beaten up by some pine borer. Huge swathes of brown as you're driving out to the ski hills. (They say it's because it's not getting cold enough over winter any more to kill them off.) I also hear these pines are being reclaimed as much as possible for tolerable construction projects. But a certain type is getting a fungal infection following the borer infestation that causes a blue stain on the good wood.
I'm wondering if these Great Lakes ashes are suffering a similar staining or other issue that may reduce their attractiveness for a nice frame. How are ashes for checking?
are you thinking about your lake house?
You've been following a few of my posts. And yes. There's a big (26 - 30") straight (for about 30') ash in the way that is in it's last stages of life. I see no bore holes, but the forester says, "I didn't think they were here yet. But this tree certainly looks like it has them. And there's a couple more over yonder." I'd like to make better use of it than firewood.
I prefer a more durable tree like white oak, but the level of finish I would be expecting would be compromised by excessive checking. But I'm told there's a kiln dryer nearby. And there's a blight starting in some areas on some of the white oaks - or so I'm told. But overall, I'm wondering if there is an appreciable difference being seen in the wholesale price and application of ash trees for this application.
aesthetic concerns only you can answer - does a light colored, open grained wood please your eye?
Far more than a doug fir or pine. Ash looks similar to oak which I prefer.
re: staining and checking -
I've cut and worked a fair amount of ash - the wood is clean and white except for a very modest amount of heartwood that displays a light gray/brown color -
as far as checking goes, there are a couple of issues - in timber framing we are talking beams, 6X6, 6X8, 8X8 and bigger - any beams that contain the heart/pith are going to check (this applies generally, not just to ash) pretty significantly down at least one face as it dries - just the nature of the material -
now say you have a straight tree, 26" in diameter (at the small end) - theoretically, it would be possible to get 4 8X8 beams out of that log, none containing the pith - (as a practical matter, it is a rare tree that is straight enough to get this good of a yield down a 20' length without a wany edge or two or three) -
now these four beams are rift sawn - the growth rings run diagonally from corner to corner of the stick - when dried, either air or kiln, these beams should check minimally, but they will go out of square - see Hoadly's 'Understanding Wood' or I'll scan a page and post it if you want me to -
take that same 26" log and saw 2 ~9X9" beams centered off each side - you then have two beams with quartersawn grain - these beams will dry pretty square and check minimally - your best quality -
but half the yield -
as a practical matter, that ash tree in the way of your dwelling isn't going to furnish but a small percent of the material for a timber frame structure - it could furnish quite a bit of accent pieces - a mantel, a beam above a wide opening, or paneling/bookcases for the library -
"there's enough for everyone"
Did I mention all of the red oaks I also have in the way? Ranging from 12" to 24".
But in reality, these will offer better service as accent pieces - trim, etc.
I'm told I have no white oaks, so if I go that route, I'll be picking out of someone's woods.
Thanks for the info regarding the cut and curl.
peteschalgor,`
Checking has more to do with drying technique than wood speices..
Most of my white oak is check free, even the big timbers..
The reason is I air dried the wood slowly for three years before I started timberframing with it.
That's both good and bad.. Good in that it minimizes checking when put up.
Bad in that the wood becomes a lot harder to build with.. massively harder!
Timbers even properly stickered, and tied together will still warp and twist like a hootcie cootchie dancer.. On top of that the wood will harden-a lot! When I planed the timbers after they were air dried for three years It usually took two sets of planer blades per timber.. When I planed wood that had recently been sawn I could count on seven to 10 timbers per set of blades and I suspect much more if I really pushed it. (I never did because I didn't forget that many timbers)...
I have 4 big (20 feet long 10 inches high 12 inches wide). Ash timbers in my house and they went up green and because of that the first season of heating caused the timbers to have massive checks in them.
I don't care because they are going to be well hidden so it doesn't matter.. I used ash because it was insanely cheap (20 cents a bd.ft. compared to 80 cents for white oak) and didn't require stainless steel fasteners like my oak does.. It was also stronger than white oak by a small amount.. The latter doesn't matter much because usually you can oversize the timbers enough to more than meet any strength requirements..
It mattered in this case, because I wanted the ceiling level to build a coffered ceiling there. so I was restricted to a 10 inch beam and I was determined to have my usual 200% over strength Using ash I wound up with 220%
Blue stain doesn't happen to ash,, usually only pine.. and it doesn't come from just pine borer killed trees, any pine that isn't properly dried can blue stain.
You can treat the ash so that it repels the borers..