Air drying lumber

Nov 19, 2004 33 Replies

I would. With the emphasis on "reasonable" environment. In my climate outside the peak of Summer I couldn't keep kilned timber remotely near the MC it was originally delivered with. Maybe for interior shopfitting work in a completed building I could do it, but certainly not for "construction".

OTOH, the only "construction grade" timber I'm likely to see is kilned, not air-dried, so this question is rather academic. And the building work that I do myself is more likely to be green timber trad-framing anyway.

On the third hand, I'm not doing construction work anyway, I'm a furniture maker and working mainly with temperate local hardwoods. There's an attitude of superiority amongst kiln operators that their timber is superior, even their boil-in-the-bag beech. yet for long-term stability it's not a patch on air-dried. I don't work to

1/8" accuracy, that's my idea of an aesthetic size increment between two adjacent rails. I think of "accurate" and "stable" as being when I can't feel any step when I run a finger over the surface, or that a joint won't start to telegraph through a veneer layer in decades to come.

Well if I could get it, I might do. I can get air-dried douglas fir, but it's premium stuff at premium prices, not construction. The real reason for construction timber being kilned is that it's cheaper that way - nothing wrong with that.

Besides which, I'm in the UK. We don't frame our houses - we're smart little piggies and build them out of bricks. 8-)

KD doug fir certainly isn't cheaper than non KD doug fir over here!

Watching a fellow and his wife building a concrete house formed up with styrofoam to be left on as insulation. From the amount of rebar, it should be around a while.

-Doug

I still don't think you appreciate what George and I are both saying - there are three sorts of timber, not two; kilned, air-dried and green or semi-green. We're not claiming that this _undried_ timber is better / drier / more stable than kilned, just that properly air-dried and long-seasoned timber is. Air-dried is the primo stuff, and expensive, because it's such a slow process.

I don't know a source for non-kilned, non-premium Douglas fir around here. OK, so the sawyers will have the odd tree, but that's negligible. If I had a timber-framing project that was using it, I'd buy it as standing trees. There's a tiny amount as decorative timber that's air-dried, but that's a rarity too. The bulk construction warehouse trade stuff is _all_ kilned. If there was any around that was cheaper because it was less than dry (which seems to be the stuff you're talking about), then it's just not visible. Almost all is imported - it's dried before they ship it.

No argument, but this is not as common in the US with framing lumber as it is with hardwoods.

In the US Borgs, you won't find KD lumber. You will see doug fir labeled as green as well as hemlock fir. That's why it turns to boat lumber asa soon as you get it out of the stack and home and why it squirts water as you drive a nail into it. To get KD, you need to go to a non Borg commercial yard.

-Doug

You need to check your labels. S-Dry is the standard for construction lumber. Has more to do with durability than stability. If you don't get wood below about 25% MC you get mold. Thus the In the US Borgs, you won't find KD lumber. You will see doug fir labeled

I'll be dipped in sh*t. Now, other than landscape timber, what for?

Can't build with green under any code.

You go down the dimensional framing lumber aisle, and other than cedar and redwood, it's all "green doug fir". And they do build with it and get it approved. As I said at the beginning of this thread, I wouldn't use it.

-Doug

Looks like green pressure treated...

Nope, just green as in green vs dry. The color is light tan. The PT is definitely green (and sometimes brown) in color and marked as pressure treated.

-Doug

Never had that problem with fresh KD DF, but my mothers 100+ year old house has full 2" rough cut DF framing and driving a nail into this stuff is almost impossible.

-Doug

This appears to be a hornets nest but I'll wade in. Kiln dried lumber has some advantages.It has been held straight while going thriugh cycles and there fore has less tendeny to warp.(Air Dried can have the same.) The sap has been set( If you saw yellow pine and air dry you might have a expierance of the rings coming apart.)The last portion of kiln drying is a heat cycle that makes the sap solid. The water held in wood is in two different parts of the board. Air drying does not release the celler water kiln drying does. The celleur water does not cause the major warpage but is a dimensional problem. Now talkiing about older furniture. The masters built there works understanding what they had and built it for that mediam. Air dryed lumber has its advaaantages and that is being dried to the area that it is going to be used. It has a better musical resonates. Its cheaper. The problem is that any wood that isn't kiln dried is considered air dried, this is totally wrong. Air dried is when it has been dried sticked and dried appropiately.

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