Will joint compound stick to plywood?

[Ted]

Hello,

I'm looking for information about finishing my basement ceiling. I plan to finish only 1/2 of the basement (an area 17' x 37' rectangle) I only have one water pipe in that area that goes to the back unfinished area. I also have a few heat ducts, but otherwise, the joist pockets are clear of obstructions. I was considering painting or staining the joists, then running a 2' border of drywall around the perimeter (to simulate a coffered ceiling look). I'd also cover the 3 ducts that run between the joists with drywall. For the underside of the plywood subfloor above, I was considering spraying it with joint compound thru a compressor driven gun. Maybe a knockdown or popcorn effect. My question is weather joint compound will stick well to the plywood subfloor? Maybe even skip painting the joists and just hit them with the compound too? Does anyone see anything the might make this un-doable?

Thanks, Ted

[mwlogs]

While compound will stick to plywood, I don't think it's a good idea, particularly in the way you are thinking. Compound is manufactured to use on drywall so it will expand and contact at basically the same rate and retain moisture (humidity) in a similar manner. Wood, including plywood would behave much differently and that could cause you problems. Add to that the fact the subfloor will have some flex to it as people and things move around upstairs, you are likely to see the compound begin to crack and flake off.

Your basic idea sounds interesting, and with some complementary paint colors I think it sounds like you could end up with an interesting effect that would also give your ceiling the appearance of being higher than if you were to drywall the entire thing. It would probably be more work, but to paint the subfloor and stain the joists might look pretty nice. Or paint the joists a different color.

Whatever you do, if you paint be sure to prime first!

Good luck!

[PipeDown]

A thin coat with a heavy texture like popcorn won't show many defects caused by uneven expansion of the materials. If you were filling in deeper gaps and such like is done when taping drywall you might have to do that in more than one coat.

I think if you prime with PVA primer, the mud will stick.. This primer is compatible with mud. It has a good chance of working

If the subfloor from the room above has any deflection, this may cause the mud to chip off later.