Cutting a Tongue-and-Groove Profile into Framing Lumber
goodomens
| Posted in General Questions on
I’m considering cutting a t&g profile into clear 2×12 framing lumber and installing as flooring (visible from below as ceiling over wide spaced timber joists). I know that it has the strength, and we like the wide plank aesthetic… has anyone done something like this? Should I be worried about how much a 2×12 will shrink and expand compared to similar 2×6 t&g commonly available for this purpose? This is for a loft.
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goodomens,
How much movement you get depends on the starting moisture content of the framing lumber, your climate, and how consistent your indoor humidity is over the whole year. With boards that wide any initial or seasonal movement is going to be quite noticeable (you will get twice what you would using 2"x6"s). Whether that's a problem depends on your tolerance for it.
Not just humidity -- I would argue that stable temperature is even more important in keeping a constant wood moisture content.
https://www.greenbuildingadvisor.com/question/wood-air-and-water-the-interplay-of-temperature-humidity-and-wood-moisture-content
DC,
Yes, very true.
I can't speak for 2x12 but can for 2x6. Installed them pretty dry but they still gapped a bit over time, having gaps about 2x that size would be noticeable.
Gaps aside, my issue with this is I can't figure out a way to install it creak free. I think the problem is the water based clear coats tend to stick a bit so boards always make some noise when walked on. I've tried putting rosin paper over the framing and between each T&G groove and still creaks. Maybe someone has a solution for this out there.
I've been a bit worried about the creaks, Akos - I'm planning on doing this is a glorified garage/barn behind my house, and had planned on doing T&G 2x6s over 2x8 rough sawn framing. The building is not currently climate-controlled but will be eventually (about a million years from now).
My thought was to put down a bead of construction adhesive (bit of a pain, it can't be too much or it'll squeeze off the edges of the joists), screw and plug the 2x6s to the joists (can't wait to saw off all those little dowels), and just finish the top with tung oil. Not sure if it's worth pre-finishing each 2x6 with tung oil so it's the same treatment on all sides. The hope is that because it's not a film-forming finish, it might be okay?
My experience is it looks better from the bottom than the top. I've seen a house where they used 4x12 joists on 48" centers and 2x6 floorboards, it looks cool from below. You want to chamfer the edges of the T&G to disguise the irregularities and also hide any gaps. From the top it just doesn't make a good floor, there's a reason you rarely see hardwood floors wider than about 5". And framing lumber is awfully soft and splintery for a floor, although maybe a Douglas fir or southern yellow pine would be OK. I've actually seen floors where they did a layer of T&G for the ceiling look, and then a layer of plywood over that as the subfloor of a conventional floor.
The other thing to look out for is that space between floor and ceiling is useful for mechanicals.
I agree with everything above. I have had good luck using this product for this kind of situation: https://www.lamcofp.com/en/products/lamfloor-structural-roof-decking-wide-board-loft-flooring/#prettyPhoto.
That looks interesting. According to the website it's made from laminated 2x4 and 2x6 so it probably ends up being cheaper than 2x12.
I really like the look of one of the pictures in their gallery, it's a post and beam interior with a 12" or so over-roof. Very clean.
They have changed the details; it used to be laminated from 2x2s or 2x3s. But it's kiln dried so it doesn't move as much as typical 2x6 decking.
I think you will find that framing lumber is framing lumber for a reason. It is not finish wood. It will be bowed warped checked waned missing knots strap marked ink stamped etc. It will vary in dimension enough before drying out to make t&g routing interesting to say the least.
20 years ago no one around me would spec 2x12 floor joists due to wood quality/shrinkage.
My roof and flooring[not finish floor] are 2 1/4 actual x5-1/2 exposed glued up of 3 pieces of wood so they could be selected when made and you have a 'good' surface.
Local sawmill? Might have affordable 1x to build up your own if you don't like the lamifloor.
Thanks for all the responses 👍
We looked at a home with soft pine floors. They were butt ugly from the dog’s nails they had dimpled surface. The disclosure form said the floor required maintenance every 6 months and the current ugly finish was only a few months old. You could clearly see everywhere the bar stool's legs had been.
Soft wood floors would be a bad idea.
Walta