Painting OSB

[wolfhawk73]

I wonder if block filler would work? It has a high solids content and can be applied in thicker layers with a 3/4" nap roller. I would think that a couple of coats of block filler with a coat of interior paint would work pretty well.

 

[MooreGarage]

Isn't that just T-111?

They look very similar, but the Smartside is a newer and better product. Mainly better water resistance (it won't delaminate like T1-11 does if it gets wet), also better insect and sun resistance. Comes pre-primed so paint goes on very nicely.

 

[lund]

Thanks. Maybe just the batch that I have is unusually smooth on both sides. I will inspect carefully for the moisture protection/wax and see if I can figure it out. I was expecting what you said and was surprised it was not obvious! The prospect of a side being lightly waxed worries me more than the smoothness with what I will do with the finishing.

 

[lund]

I wonder if block filler would work? It has a high solids content and can be applied in thicker layers with a 3/4" nap roller. I would think that a couple of coats of block filler with a coat of interior paint would work pretty well.

That is a good thought to do in place of a primer coat over a drywall mud skim. It might bond much more durably than a very light skim coat of drywall mud + light post sanding. The drywall mud skim would likely be easier, faster, and cheaper though ... but together with primer it is probably roughly equal time and expense wise.

 

[NUTTSGT]

They look very similar, but the Smartside is a newer and better product. Mainly better water resistance (it won't delaminate like T1-11 does if it gets wet), also better insect and sun resistance. Comes pre-primed so paint goes on very nicely.

Yeah, T1-11 was originally a plywood product. It was followed by Smart panel or EZ-panel which was a OSB based product.

Now Smart-Side is a "trademark" name from a manufacturer.

All boils down to the same design/layout look but slightly different product or manufacturer. Basically the Kleenex, Puffs or tissue debate.

 

[Notgrownup]

Too sorry ?


I thought it looked good and left it without a top coat when I first did it. . . . looks good, leave it like that. . . . . later when I made a change and needed to touch up some spots and do paint correction, that's when I saw how bad it looked. Yellowed vs fresh white.

Yep, I had all intent of painting the inside of my shop but life got in the way.

 

[wolfhawk73]

That is a good thought to do in place of a primer coat over a drywall mud skim. It might bond much more durably than a very light skim coat of drywall mud + light post sanding. The drywall mud skim would likely be easier, faster, and cheaper though ... but together with primer it is probably roughly equal time and expense wise.

Drywall mud would definitely be cheaper, but it'd be a lot more work, especially with me, since I can paint well but my mudding skills are sorely lacking. I'd worry that the drywall mud would crack or come loose, since OSB is liable to expand and contract more than drywall with temp and humidity changes.

 

[lund]

Stuff I got at Lowe's last week is very easy to tell the difference. It's not smooth as in slick. You just dont see or feel the edges of the chips like the other side.

Agree. I was being poorly observant. When I looked it is pretty obvious which side is finished.

I will test process (skim coat, prime, and paint) an off-cut section and see how it looks and bonds. It should be fine. The wax is my main worry.

 

[ncfireman1918]

I did OSB in my shop 5 years ago. 2 coats of Kilz oil based primer, 2 coats Valspar gloss white latex paint in 5 gallon buckets. It was a pain to do at the time, but I have been very happy with how well it has held up. If anything gets on it, I can just wipe it off. I am careful not to weld or throw sparks too close to the walls, but have not had any issues with it so far. I did use a yardstick laid flat underneath each piece as I hung it, just to keep it off the slab.

 

[KenC]

Yeah, T1-11 was originally a plywood product. It was followed by Smart panel or EZ-panel which was a OSB based product.

Now Smart-Side is a "trademark" name from a manufacturer.

All boils down to the same design/layout look but slightly different product or manufacturer. Basically the Kleenex, Puffs or tissue debate.

T-111 is still plywood, usually 3 ply and yellow pine, at least in our market (OK). Smart side is an OSB product with an embossed cedar wood texture. Also very heavy as it seems to have a high binder content compared to normal OSB. Usually comes primed but also available prefinished.

I just used some of their Smart Trim boards. 5/4 sizing for corners etc. Really heavy! and Hard! Air nails or screws as hand driven bend really easily. Combination of Chinese steel and my aim.

 

[NUTTSGT]

T-111 is still plywood, usually 3 ply and yellow pine, at least in our market (OK). Smart side is an OSB product with an embossed cedar wood texture. Also very heavy as it seems to have a high binder content compared to normal OSB. Usually comes primed but also available prefinished.

You're correct Smart-Side is a OSB product just something better than regular OSB. Better binders and exterior layer of product with the 4" or 8" groove pattern. Much like Zip to regular OSB, something better in the evolution of building products.

I think we're on the same page. Plywood T1-11 still around, I just meant it was , as far as I know, the first panel product with the groove pattern in it. Stuff with **** up paint or stain in cast quantities.

 

[lund]

Progress report for those interested: I worked on one section of the basement wall with OSB panels this weekend: trimmed panels, stapled on frame, sanded lightly, skim coated very lightly with drywall mud, sanded with drywall sanding screen + vac, wiped, primed, and then touched up parts (cut out loosely bonded chips, filled cutouts with drywall mud, sanded again, and primed spots). At this phase it is looking pretty good ... better than I had expected. BUT, it has taken more effort than I thought it would be due to all the sanding, priming, etc with post-finish touchup. It might have made sense to use a more (expensive) finished panel product as some suggested. The wall will be very strong though. One thing that I was not anticipating is that it is very hard to see limited blemishes (skim void fill failures and loose bonded OSB chips) that you might want to fix before priming. So if you are picky, some degree of touchup work will be needed to approach two rounds of surface fill and priming. That being said, it is looking better than I thought: the panel retains a slight texture from the chips below (chips would be much stronger expressed without the light drywall mud skim with post sanding), but nicely uniform with faint, consistent chip texture. Using air gun staples was probably a good decision. Those filled nicely with drywall mud without being visible post skim coat. Filled drywall screw holes probably would have been very visible (round smooth areas in a regular pattern). One has to be careful to keep the drywall mud skim very thin, or you will end up with thicker too smooth patches (which also might not bond well ... I wanted just features and borders lightly filled). Watering down the mix helped with keeping needed power for drywall tooling down.

I will post some pics later with a summary when I get some sections painted. But it is looking like more than anticipated effort to implement, but it is cheap and it should look pretty good, be super strong, etc. So a mixed bag. Probably ok for home DIY without time charges and being able to patiently work on it in short piecemeal intervals for touchup.

 

[Youngandfree]

Progress report for those interested: I worked on one section of the basement wall with OSB panels this weekend: trimmed panels, stapled on frame, sanded lightly, skim coated very lightly with drywall mud, sanded with drywall sanding screen + vac, wiped, primed, and then touched up parts (cut out loosely bonded chips, filled cutouts with drywall mud, sanded again, and primed spots). At this phase it is looking pretty good ... better than I had expected. BUT, it has taken more effort than I thought it would be due to all the sanding, priming, etc with post-finish touchup. It might have made sense to use a more (expensive) finished panel product as some suggested. The wall will be very strong though. One thing that I was not anticipating is that it is very hard to see limited blemishes (skim void fill failures and loose bonded OSB chips) that you might want to fix before priming. So if you are picky, some degree of touchup work will be needed to approach two rounds of surface fill and priming. That being said, it is looking better than I thought: the panel retains a slight texture from the chips below (chips would be much stronger expressed without the light drywall mud skim with post sanding), but nicely uniform with faint, consistent chip texture. Using air gun staples was probably a good decision. Those filled nicely with drywall mud without being visible post skim coat. Filled drywall screw holes probably would have been very visible (round smooth areas in a regular pattern). One has to be careful to keep the drywall mud skim very thin, or you will end up with thicker too smooth patches (which also might not bond well ... I wanted just features and borders lightly filled). Watering down the mix helped with keeping needed power for drywall tooling down.

I will post some pics later with a summary when I get some sections painted. But it is looking like more than anticipated effort to implement, but it is cheap and it should look pretty good, be super strong, etc. So a mixed bag. Probably ok for home DIY without time charges and being able to patiently work on it in short piecemeal intervals for touchup.

So you didn't put the smooth side out?

 

[lund]

So you didn't put the smooth side out?

I used smooth & treated side out to finish. First I lightly sanded with coarse sandpaper (random orbit) before the drywall mud skim, then post drywall screen sanded so the mud only filled voids between chips and defects on the smooth side. Looked like it bonded well and the primer soaked into the thin layer to lock things in better. The smooth side skim coats better with less work and compound (did some test processing on off cuts).

 

[mike93lx]

I think I would use a thick nap roller and some wetted down mud. Roll it on, then use a wide knife to swipe off excess. It should cut sanding a lot.

I've used this to thinly coat drywall when I wanted to kill any texture. May not be ideal for how rough osb is, but I'd try it

 

[lund]

I think I would use a thick nap roller and some wetted down mud. Roll it on, then use a wide knife to swipe off excess. It should cut sanding a lot.

I've used this to thinly coat drywall when I wanted to kill any texture. May not be ideal for how rough osb is, but I'd try it

Maybe that is a good idea.

But one issue I noticed is that very wet drywall mud on OSB + Latex Paint primer may have the effect of causing some poorly bonded OSB chips to loosen enough where I was touching up after priming (cutting out, using more drywall mud filler, then priming again). I was not expecting that. Maybe this is inevitable (loose chips come loose). But in retrospect, it might have been too much water going on the surface with loose chips exanding resulting in a few bubbling up and more touch up to fix them. It might have been better to first prime with an oil based primer then drywall mud-skim, lightly sand, and prime again before painting. Some people suggested using oil-based primer. That might also lessen the issue. That being said, it came out well. Just more effort (mostly due to touchup) than I was thinking it would take.

 

[The Cobbler]

might have been better to first prime with an oil based primer

this for sure .

 

[The Cobbler]

use a thick nap roller and some wetted down mud. Roll it on, then use a wide knife to swipe

this works. I also used my texture gun to do the same thing, spray some mud on and swipe it with a wide knife

 

[Youngandfree]

Maybe that is a good idea.

But one issue I noticed is that very wet drywall mud on OSB + Latex Paint primer may have the effect of causing some poorly bonded OSB chips to loosen enough where I was touching up after priming (cutting out, using more drywall mud filler, then priming again). I was not expecting that. Maybe this is inevitable (loose chips come loose). But in retrospect, it might have been too much water going on the surface with loose chips exanding resulting in a few bubbling up and more touch up to fix them. It might have been better to first prime with an oil based primer then drywall mud-skim, lightly sand, and prime again before painting. Some people suggested using oil-based primer. That might also lessen the issue. That being said, it came out well. Just more effort (mostly due to touchup) than I was thinking it would take.

I haven't seen dampness being an issue on the smooth coated side, not loose chips coming out. And I just cut some last week to use as form boards for some concrete.

 

[lund]

I haven't seen dampness being an issue on the smooth coated side, not loose chips coming out. And I just cut some last week to use as form boards for some concrete.

It is possible that i had a not super batch of OSB in my purchase. I also lightly sanded the smooth side to hopefully enhance bonding. That may have enhanced water distortions on surface chips in the panels.

Clarification: I should also add that I am pretty picky: The imperfection issues I was fixing were mostly pretty small. Many might ignore them completely. The imperfection touch up took considerable time, but came out very well. For a large area it would be more painful to do what I was (about 4 small loose bond chip repairs per panel).

 

[DGersic]

Dude, it’s OSB. It’s not supposed to be a perfect surface.

 

[lund]

Dude, it’s OSB. It’s not supposed to be a perfect surface.

Sure ... but when you can find a way to improve the scope of application and the outcome with a cheap product that is also strong and versatile, why not do so ? Price the difference to high finish sanded plywood and you will see what I mean: it is about 3x the cost. End results I am getting that benefited from the discussions look pretty good and should perform well.