[newbie] green Douglas fir: use it immediately, or wait to dry?

[Florin Andrei]

To keep a piece of machinery raised a little off the ground, I'm making a short, square support: legs made of 4x4, about 1.5 ft long each, and 2x6 planks on the side, about 3 ft long each. I'll keep it as simple as possible, flat joints everywhere, carpenter's glue and 1/4" lag screws. Like a square, very strong "coffee table" but without the table top.

I bought the wood, it's green Douglas fir (cheapest I could find, that's why), and it's probably not dry. It's not dripping wet, but it's heavy, and it just feels and smells like wood that's pretty fresh.

I have the option of making the thing this week-end, or wait 1 or 2 weeks. If I wait, I could leave it to dry outside (California, pretty hot, no rain). Either way, it will be several weeks before I coat it with spar urethane, so it will have time to dry out before that, whether it's assembled or not.

My question is - should I use it now, or should I wait a little? Is the wood less likely to crack if it's wet? Will the glue stick better to dry wood? Other pros and cons?

[Jamie Buxton]

A couple of weeks, even in California, will not dry a 4x4 very much, or even a 2x6. So you may as well make your platform now. Folks build houses with wet Doug Fir, so it is possible to make a sturdy structure with it. As it ages and dries, it may check or warp a bit, so it ain't fine furniture, but it doesn't sound like that's what you're doing.

Ordinary carpenters glue doesn't bond very well to wood that is soaking wet. The glue cures by getting rid of water, so the water in the wood interferes with that. Make your connections mechanically -- screws, nails, etc. You might look into Simpson Strong Tie brackets.

[Kent A Bathurst]

GDF is the standard, more or less, for framing houses/construction/etc. on The Left Coast.

It is stable, and does not warp/twist/cup/etc/etc as it dries. At least. not to any significant degree once nailed in place. Alla them there jillions of houses and apartments are framed with GDF.

As Jamie correctly notes, glue is a waste of time on green lumber - mechanical fasteners - screws, nails, bolts, whatever.

No idea how long you need to wait to varnish, but then, at my spot on the time-space continuum, shop framing, shop tables and fixtures, etc. never get varnished anyway - that is a complete waste of my time , but YMMV, in which case I have no argument with you or anyone else. Just sayin........ I am typing from a 18 year-old work bench, who's varnish [as recently noted in another thread] is cigarette ash and spilled cabernet. Plus - some spilled dye and Super Tuscan wines - I tend not to sand those out - cost me too much. :D

The GDF is a fine choice for what you are doing. No need to wait - tee it up.

[Florin Andrei]

A couple of weeks, even in California, will not dry a 4x4 very much, or even a 2x6. So you may as well make your platform now. Folks build houses with wet Doug Fir, so it is possible to make a sturdy structure with it. As it ages and dries, it may check or warp a bit, so it ain't fine furniture, but it doesn't sound like that's what you're doing.

Fine furniture it sure ain't. :) Just a sturdy platform.

I'll get started soon then.


Ordinary carpenters glue doesn't bond very well to wood that is soaking wet. The glue cures by getting rid of water, so the water in the wood interferes with that.

I see.

I also have plenty of epoxy, having used it for other projects before. That one doesn't care about humidity. As long as it penetrates the wood to some extent, it should be fine, I guess.


The GDF is a fine choice for what you are doing. No need to wait - tee it up.

Got it, thanks!

[Rich Engelhardt]

I wonder if something like Gorilla Glue (moisture cured urethane) would work?
I used some of that on some fairly wet treated wood once & it seems to be holding up after about 10 years.

[Jamie Buxton]

I wonder if something like Gorilla Glue (moisture cured urethane) would work?
I used some of that on some fairly wet treated wood once & it seems to be holding up after about 10 years.

Yeah, it or urethane construction adhesive is more likely to cure on wet wood than carpenters glue. But I'd be cautious about depending on it structurally. I tested Gorilla Glue on dry lumber, and found that the joint was considerably weaker than yellow glue. When stressed to failure, the glue itself would break, whereas the yellow glue is stronger than the wood flanking it.

House-construction guys use urethane construction adhesives mostly to squeak-proof or seal. The real strength in their joinery comes from nails.

[scott vroom]

I've done a lot of framing here in California with green doug fir and actually prefer green because it doesn't split easily when using 16D framing nails, and it tends to not twist once nailed in place.

Leaving green fir in the sun will cause it to twist/cup/warp etc very quickly and I strongly recommend against doing that unless you plan to face joint, plane, and rip to flatten and square. You're better off buying kiln dried wood or just using the green fir immediately after bringing it home from the lumberyard. And glue for the project you described isn't necessary....mechanical fasteners are all that's needed.

[daniel lane]

Leaving green fir in the sun will cause it to twist/cup/warp etc very quickly and I strongly recommend against doing that unless you plan to face joint, plane, and rip to flatten and square. You're better off buying kiln dried wood or just using the green fir immediately after bringing it home from the lumberyard.

+1. I bought some green DF 2x6s back in CA a few years back to use for a similar project. Wound up not getting around to it that weekend, and the next several were lost due to holidays/kids/etc. By the time I got back to them a month or so later, they were all twisted and cupped, and I wound up jointing, planing, etc. as Scott suggests, all the time cursing myself for not doing it that first weekend.


daniel

[Kent A Bathurst]

Leaving green fir in the sun will cause it to twist/cup/warp etc very quickly........

Yeah - Scott - you are absolutely correct.

But that is not what the material is intended for.

Frame the house, enclose it, and it will dry slowly and consistently over time.

You gotta get it into its final assembled configuration, without a long sunny vacation.

[Frank Drew]

Frame the house, enclose it, and it will dry slowly and consistently over time.



Doesn't framing with wet lumber leave the house vulnerable to black mold, in addition to cracked spackle, etc?

Around here, the norm, as far as I know, is to frame with kild dried lumber; I live on a freight rail line and over the past decade or so there seems to have been an almost complete adoption of wrapping the bundles of lumber that i see go by (no sense drying the lumber just to let them get rained on.)

[Kent A Bathurst]

Doesn't framing with wet lumber leave the house vulnerable to black mold, in addition to cracked spackle, etc?

Around here, the norm, as far as I know, is to frame with kild dried lumber; I live on a freight rail line and over the past decade or so there seems to have been an almost complete adoption of wrapping the bundles of lumber that i see go by (no sense drying the lumber just to let them get rained on.)

Legit questions; I don't have the answers, Frank.

I can only tell you that the GDF is the deal on the Left Coast. Boat loads - literally - giant ocean-going barges - fulla the stuff come in constantly. Not like back in the early 2000's home building insanity, but still - breathtaking volume of the stuff.

Also - in VA - there isn't an equivalent species in terms of stability, grain structure, etc. Would not work with Easter Canada Spruce[which is the stuff your homes are framed of] and Southern Yellow Pine would be laughable as it dried.

[Chris Padilla]

I've done a lot of framing here in California with green doug fir and actually prefer green because it doesn't split easily when using 16D framing nails, and it tends to not twist once nailed in place.

I have a fair amount of redwood 2x material in my house. I just gutted my master bath...almost all redwood framing studs.

[Florin Andrei]

Leaving green fir in the sun will cause it to twist/cup/warp etc very quickly and I strongly recommend against doing that unless you plan to face joint, plane, and rip to flatten and square. You're better off buying kiln dried wood or just using the green fir immediately after bringing it home from the lumberyard. And glue for the project you described isn't necessary....mechanical fasteners are all that's needed.


+1. I bought some green DF 2x6s back in CA a few years back to use for a similar project. Wound up not getting around to it that weekend, and the next several were lost due to holidays/kids/etc. By the time I got back to them a month or so later, they were all twisted and cupped, and I wound up jointing, planing, etc. as Scott suggests, all the time cursing myself for not doing it that first weekend.

I had no idea. That was very informative, thank you.

[Patrick McCarthy]

I have a fair amount of redwood 2x material in my house. I just gutted my master bath...almost all redwood framing studs.

Bet your house was built pre 1960

[Jamie Buxton]

Doesn't framing with wet lumber leave the house vulnerable to black mold, in addition to cracked spackle, etc?

Around here, the norm, as far as I know, is to frame with kild dried lumber; I live on a freight rail line and over the past decade or so there seems to have been an almost complete adoption of wrapping the bundles of lumber that i see go by (no sense drying the lumber just to let them get rained on.)

Here in California, stick-built houses are always framed with green lumber. On most projects there are several months between when framing goes up and when drywall goes on. In that interval, the roof goes on, windows and exterior sheathing go on, wiring and plumbing go in, and such. During that time, the framing lumber gets to dry out somewhat. It only needs to get to 19% EMC to prevent the growth of mold. (19% is by no means completely dry. It will eventually get down to 9% or so, shrinking all the while. But it won't be growing mold.) As it happens, getting from green to 19% is the easy part of the drying process; water between the cells is coming out. From 19% to 9% is more difficult; water from inside the cells is coming out.

In more humid areas like much of the East and Southeast, green lumber may not dry enough before the drywall goes on, so builders use kiln-dried construction lumber.


It is worth noting that "Kiln-dried" means something different in the construction-lumber world than it does in the hardwood-lumber world. In construction lumber, the industry standard for kiln dried is 19% EMC -- because that's where mold ceases to be an issue. In hardwood lumber, kiln operators generally go to 9-10% EMC, because cabinetmakers and trim carpenters don't want the lumber to be shrinking after it is installed.

[Chris Padilla]

Bet your house was built pre 1960

It was built in the early 70s actually. The lumber even has a stamp on it indicating it is a "redwood stud." Pretty interesting.

[Chris Padilla]

As far as framing with green lumber goes, over the last year or so I've been slowly building up a stock of 2x4s for my master bath remodel. Any time I went into one of the borgs, I'd cull the stack of studs to find rift/quarter sawn pieces to take home and toss on my wood rack. Most of those culled studs have dried a bit and managed to stay straight. Since I'm putting large tiles in my shower, I went ahead and jointed all of the studs, added (glued and pinned) a strip of 1/4" plywood to the jointed face, and then ripped them all back to 3.5" wide. I now have a very nice straight wall with studs that have sharp edges. It looks kind of funny from a distance where I have 3 studs stacked next to each other (cripple, jack, king) as they almost look like a solid chunk of wood! But my wall is dead flat, straight, planar!! :)

[Phil Stone]

I'll volunteer an answer to a question which wasn't asked here. If you *do* want to use GDF for woodworking, it can be air dried quite effectively. For my workbench build, I bought 2 X 12 GDF, cut it to 8 ft. lengths (to fit my drying space), then coated the exposed endgrain with a paraffin/mineral spirits emulsion slopped on with a paint brush. I stacked and stickered it (in the garage) carefully, and then weighed a couple of representative pieces every day. In the summer here in California's Central Valley, we get huge swings of humidity on a daily basis, from 90% overnight to as low as 20% mid-day, but the overall average is around 40-60% on a given day. Anyway, under these conditions, it took about two months for the wood to stop losing weight.

[Frank Drew]

Here in California, stick-built houses are always framed with green lumber. On most projects there are several months between when framing goes up and when drywall goes on. In that interval, the roof goes on, windows and exterior sheathing go on, wiring and plumbing go in, and such. During that time, the framing lumber gets to dry out somewhat. It only needs to get to 19% EMC to prevent the growth of mold. (19% is by no means completely dry. It will eventually get down to 9% or so, shrinking all the while. But it won't be growing mold.) As it happens, getting from green to 19% is the easy part of the drying process; water between the cells is coming out. From 19% to 9% is more difficult; water from inside the cells is coming out.


Very interesting, and thanks for the follow up, Jamie.