Painting OSB

[lund]

I am making a basement partition (2x4 framed, basement dry etc). I am going to sheath it with OSB sheets (1/2"). Basement edge/foundation walls are well sealed and have closed cell foam sheets covered by drywall (primed & painted). Edge wall sheathing and insulation is anchored by 1 1/2 furring strips (same thickness of foam panels under drywall) over a poured foundation with no leaks and a good french drain all around on the outside (no water infiltration). The basement is a pretty steady cool temp year round (mid Michigan) with light heating and humidity is low (particularly in the winter). So there has been no condensation issues. The drywall walls are finished smooth.

I want to paint the OSB sheets to match the perimeter/foundation wall. I will lightly sand them then prime and paint. It does not need to be super, but better if it does not look like ****.

Question: Are their special considerations to finishing/painting OSB. I figure I should heavily prime it (2 coats?) then paint two coats. Is that enough or do I need to use some product to seal the OSB chip grain better first? Also is there a preferred face (one with alignment lines or flip side) to paint that might adhere better? I plan on construction adhesive + staple the panels. I will likely use thin flat vertical molding strips on panel seams and have baseboard and top molding (matching drywall). That should avoid seam cracks.

 

[dcg9381]

I have painted OSB in my shop. It takes two coats of (BEHR MARQUEE) paint to get consistent coverage. I did not prime it. We used a dark brown and side didn't matter for that color.

If you want to seal it, sand it, get the texture smoother, you're probably better off with a different material (depending on what your time is worth and what a "sandable" sealant costs). I use epoxy on plywood for certain projects, but the cost of applying two coats of epoxy and sanding it isn't insubstantial. The smoother it is, the more imperfections will show... Nice thing about OSB is it's consistently imperfect.

 

[MooreGarage]

Depending on how many panels you need, an option might be to use Smartside panels instead of OSB. I went this route in my garage. It was about triple the price per panel over OSB, but so much less work than drywall. The panels overlap at the edges for a seamless look, and on the ceiling, I used 1x4's to cover the **** seams. I checked with the manufacturer, and the panels are low VOC and safe for indoor use.

 

[lund]

I have painted OSB in my shop. It takes two coats of (BEHR MARQUEE) paint to get consistent coverage. I did not prime it. We used a dark brown and side didn't matter for that color.

If you want to seal it, sand it, get the texture smoother, you're probably better off with a different material (depending on what your time is worth and what a "sandable" sealant costs). I use epoxy on plywood for certain projects, but the cost of applying two coats of epoxy and sanding it isn't insubstantial. The smoother it is, the more imperfections will show... Nice thing about OSB is it's consistently imperfect.

Thanks. I will be using a similar paint and if I prime it with some very light post sanding perhaps that will be enough. I would not mind some grainy look (basement partition for storage/game area closed off from shop area for dust etc) so it does not need to be high level. Just hopefully not look like ****. I agree if super smooth all imperfections will be clear (staple fills etc) so that would likely be a bad idea on top of the extra cost and effort.

Some say there is a preferred OSB side for less waxy sealant that paint would adhere to better ... but in my case (Weherhaeuser OSB) was not sure looking at the panels. But one side had a cut line grid. The opposite might have some sealant (was not sure) since it might have been more waxy if not my imagination (not big diff evident).

 

[lund]

Depending on how many panels you need, an option might be to use Smartside panels instead of OSB. I went this route in my garage. It was about triple the price per panel over OSB, but so much less work that drywall. The panels overlap at the edges for a seamless look, and on the ceiling, I used 1x4's to cover the **** seams. I checked with the manufacturer, and the panels are low VOC and safe for indoor use.

Tried to attach an image, but keep getting an error every time I try, so sorry no pic...

Thanks.

In my case I have the OSB panels and have been trimming it to fit so I am frozen in that choice now. What you say probably makes sense for a higher level finish. I was going on the cheap and thought OSB lightly finished might be ok as lightly irregular. But yeah, if wanting better/smoother, it probably makes sense to pay more for easier to finish panels. I liked that the OSB choice would be structurally strong too (wall is in line with mid support span for floors above).

I suspect/hope outgassing fumes should not be not too bad (just one wall) long term since OSB is now used all over in framing and I will paint/seal them. I could probably let the panels sit in the garage a month or so to help reduce inside outgassing somewhat when mounted. I was not thinking about that aspect (duh). But my kids are teens now, so might be through the most problematic stages to limit that kind of exposure ... plus most newer sheet materials are way better this way than years ago since formaldehyde use was stopped or drastically cut.

I will use ~3/16" thick x ~1 1/2" batten molding with light staples to hide vertical seams (every 4').

 

[DGersic]

I painted OSB on my garage walls. Two coats of external primer, two coats of exterior latex. Looks ok to me. It looks like painted OSB. I don’t think there’s really any good way to get a smooth painted surface from OSB. If you want smooth, use something else.

 

[lund]

I painted OSB on my garage walls. Two coats of external primer, two coats of exterior latex. Looks ok to me. It looks like painted OSB. I don’t think there’s really any good way to get a smooth painted surface from OSB. If you want smooth, use something else.

Thanks.

I am fine with some relatively uniform OBS pattern texture to the surface. I plan on doing the same primer + paint layering that you did. So it is good to see it worked for you. I was mostly wondering if filler first was advisable to make it a little more uniform etc. Sounds like primer layers and thicker paint may be enough.

 

[The Cobbler]

a heavy knap on the roller and roll away . 2 coats should cover it all . and It will look like painted OSB

 

[dcg9381]

Here's mine.. Nothing special, didn't work to fill the gaps, I kept the sheets 4x8 as much as possible and used screws as I want to have access behind the walls in the future.

 

[Stelzer]

If you're using a lighter topcoat, a primer would be best. If you'll be going with a dark color, a primer isn't necessary unless it'll be subjected to moisture. I'd strongly advise against using any exterior primers for interior painting. Although they can and do work, they also off-gas much more and much longer than interior coatings. There's no drawback to using a primer first though, other than time & money, but there would be absolutely no advantage to priming it twice, since primer contains very little hide.

 

[lund]

If you're using a lighter topcoat, a primer would be best. If you'll be going with a dark color, a primer isn't necessary unless it'll be subjected to moisture. I'd strongly advise against using any exterior primers for interior painting. Although they can and do work, they also off-gas much more and much longer than interior coatings. There's no drawback to using a primer first though, other than time & money, but there would be absolutely no advantage to priming it twice, since primer contains very little hide.

Good point on the primer. I was thinking more of using a thicker primer like a light filler to fill valleys between strands in the OSB sandwich. But if that is the goal, it is probably better to use a product first to so that specifically and stick to using the primer for improved sealing and adhesion.

 

[lund]

Here's mine.. Nothing special, didn't work to fill the gaps, I kept the sheets 4x8 as much as possible and used screws as I want to have access behind the walls in the future.

Thanks. That looks fine for the purpose. I will be a bit lighter color. My partition wall should not need to ever be opened up.

 

[lund]

I painted OSB on my garage walls. Two coats of external primer, two coats of exterior latex. Looks ok to me. It looks like painted OSB. I don’t think there’s really any good way to get a smooth painted surface from OSB. If you want smooth, use something else.

That seems to be consensus.

I am fine with it looking like painted OSB with a relatively uniform pattern. The staples on the beams between seams may be the biggest issue ... they may become very visible when filled and painted. Screws would probably be worse. But even if they are visible, I can live with that. It does not need to win some Martha Stewart home beautiful award.

 

[lund]

Depending on how many panels you need, an option might be to use Smartside panels instead of OSB. I went this route in my garage. It was about triple the price per panel over OSB, but so much less work than drywall. The panels overlap at the edges for a seamless look, and on the ceiling, I used 1x4's to cover the **** seams. I checked with the manufacturer, and the panels are low VOC and safe for indoor use.

That does look pretty good. Likely better than what I will have with the OSB. But that is ok for my use.

Come to think of it, fiber-cement type panels might be good for similar garage wall & ceiling sheathing too. It might make things more fire resistant. I doubt that it would survive a good cooking from a car gas tank or large EV battery pack. But it might work to give more cook through time and prevent home ignition from small fires ... not that I would ever have accidents working on stuff in the garage

 

[joco]

Do the. Math, I bought a house that had a fairly new shop, 40’ x 80’ that was insulated and covered in 1/2” OSB prior to purchasing. By the time I bought oil based primer, 2 coats, and at least 2 coats of paint I opted for metal roofing on the walls. Turned out great IMO, im in it for $1800 and a few days of my labor. FYI, I hate painting.

 

[finn]

My shop has white metal on the upper 8’ of the walls, and painted osb on the lower 8’. It’s still pretty rough, though. Looks like a couple coats of paint, but I don’t love it.

I’m thinking of doing a skim coat of drywall mud and a light sanding to make it look a little better. Not looking forward to the mess, though.

 

[lund]

Do the. Math, I bought a house that had a fairly new shop, 40’ x 80’ that was insulated and covered in 1/2” OSB prior to purchasing. By the time I bought oil based primer, 2 coats, and at least 2 coats of paint I opted for metal roofing on the walls. Turned out great IMO, im in it for $1800 and a few days of my labor. FYI, I hate painting.

Interesting idea. Has some strong logic to it. But one issue is once metal gets dented it is hard to repair. OSB would be way stronger and panels could be easily replaced & matched if any big accidents. But if you bought a few extra metal roofing panels it would be easy to make a few rounds of repair for whatever dings that you did not want to live with.

 

[The Cobbler]

But one issue is once metal gets dented it is hard to repair

this.. and it doesn't take much of a ding to look like ****. also I prefer a flat wall as opposed to a corrugated wall, just looks better imo , but to each their own.

 

[lund]

My shop has white metal on the upper 8’ of the walls, and painted osb on the lower 8’. It’s still pretty rough, though. Looks like a couple coats of paint, but I don’t love it.

I’m thinking of doing a skim coat of drywall mud and a light sanding to make it look a little better. Not looking forward to the mess, though.

I was thinking of doing a very light drywall mud skim coat and sand (not so messy/dusty with a good vac attachment and only light skim and sand) before priming and painting two coats with rollers. That should make it a little less rough and not lead to adhesion problems (mud should bond well in small chip transitions). Primer should also soak into the remaining mud skim after sanding to help it stay bonded in the features.

I am tempted to try this to match the other walls a little more closely. The skimming and sanding should go quickly in the ~120' of wall sheathing that I would need to do. Also it would be no issue if it does not work well (say look a little rougher) insofar no bonding issues are triggered.

 

[Renegade1LI]

Problem with skim coating osb is it will have a skip trowel look, never really flat. Why not use dry wall? Unfortunately trying to get osb smooth is like trying to pick up a turd by the clean end.

 

[joco]

Interesting idea. Has some strong logic to it. But one issue is once metal gets dented it is hard to repair. OSB would be way stronger and panels could be easily replaced & matched if any big accidents. But if you bought a few extra metal roofing panels it would be easy to make a few rounds of repair for whatever dings that you did not want to live with.

already replaced 1 sheet where I went into a pallet too deep , forks left 2 dents. Less than a 5 minute repair, 6 screws and done.
I caught this metal on sale at $1.99 a foot so at $16 a sheet I have several spares tucked away.

 

[Notgrownup]

I painted mine with Kilz primer in my shop and actually left them alone the coverage was so good but it’s a shop….

 

[bdbecker]

I was thinking of doing a very light drywall mud skim coat and sand...

My Dad did this in his garage. It did help smooth out the variations quite a bit. It still looks like OSB if you look hard enough, but to the untrained eye, it just looks like an interesting wall texture.

 

[lund]

My Dad did this in his garage. It did help smooth out the variations quite a bit. It still looks like OSB if you look hard enough, but to the untrained eye, it just looks like an interesting wall texture.

Thanks. That sounds like what I wanted. Garages would have more temp variation, so if it bonded well there, it should be fine in a dry basement.

 

[lund]

already replaced 1 sheet where I went into a pallet too deep , forks left 2 dents. Less than a 5 minute repair, 6 screws and done.
I caught this metal on sale at $1.99 a foot so at $16 a sheet I have several spares tucked away.

Sounds good insofar as the stock lasts long enough for whatever repairs are wanted. I have little luck with much remaining the same over extended time ... but I figure OSB should remain more or less the same.

 

[lund]

Problem with skim coating osb is it will have a skip trowel look, never really flat. Why not use dry wall? Unfortunately trying to get osb smooth is like trying to pick up a turd by the clean end.

I mean just very light skimming and sanding to part fill chip boundaries to make the chip texture a bit less pronounced when painted, but still retain some texture. I would not try to get it really flat and doing only light fills with sanding should not leave trowel streaks. But I agree if I wanted it super smooth, OSB would likely be a losing battle relative to drywall or other choices.

I agree Drywall is easier to finish. But I wanted OSB to add structural strength under the mid-span floor support that I am framing in. Maybe that is an overkill in Michigan where I live now, but I am used to overbuilding stuff from extended time in Cali where we were always waiting the next big earthquake. Maybe this will leave us more ready for a record size Michigan tornado ... that would fit my general luck pattern!

 

[NUTTSGT]

I painted mine with Kilz primer in my shop and actually left them alone the coverage was so good but it’s a shop….

I used oil-based Kilz in my garage as well. However, it does need to be top coated as it will yellow over time, slow enough that you probably won't notice it until you try to touch up a spot.

Kilz oil-based does great priming OSB and two coats will cover nicely. The biggest problem is the smell while drying, in a garage or shop it's not to big of a deal, in the house during winter. . . yuck.

 

[four.cycle]

^ What he said. (And @DGersic):
To coats of "KILZ" and two coats of latex, applied with a deep-nap roller. (really lay the stuff on.)
I did not use exterior, because it's an interior room (and heated by the hot water heater) so that would have been overkill.
Looks fabulous - 25 years later. (Photo was taken a few years back, but it's still the same) You can just barely see the "texture" from the OSB on the lower left.

 

[borgdog]

one coat latex KILZ and one coat of paint + a few dot touchups when dried on the end wall in one of the game rooms (I have a pinball problem). I've done several areas in 3 houses with OSB, including 2 shops, all the same way. never cared about the seams, it's a cheap utility wall cover that can easily be removed if need to do wiring or whatever (note sub panel on wall)

 

[four.cycle]

an easily be removed if need to do wiring or whatever (note sub panel on wall)

^ exactomundo.
at the very top of the image I just posted above, you can see the bottom of the main panel. I cut the panel to the immediate right of the box and attached it with very visible screws so that it can be easily removed to get at/into the box if necessary without ripping the wall apart.

 

[Youngandfree]

I mean just very light skimming and sanding to part fill chip boundaries to make the chip texture a bit less pronounced when painted, but still retain some texture. I would not try to get it really flat and doing only light fills with sanding should not leave trowel streaks. But I agree if I wanted it super smooth, OSB would likely be a losing battle relative to drywall or other choices.

I agree Drywall is easier to finish. But I wanted OSB to add structural strength under the mid-span floor support that I am framing in. Maybe that is an overkill in Michigan where I live now, but I am used to overbuilding stuff from extended time in Cali where we were always waiting the next big earthquake. Maybe this will leave us more ready for a record size Michigan tornado ... that would fit my general luck pattern!

Did you put the smooth side out?

 

[Notgrownup]

I used oil-based Kilz in my garage as well. However, it does need to be top coated as it will yellow over time, slow enough that you probably won't notice it until you try to touch up a spot.

Kilz oil-based does great priming OSB and two coats will cover nicely. The biggest problem is the smell while drying, in a garage or shop it's not to big of a deal, in the house during winter. . . yuck.

To be honest a little bit, I was too sorry to top coat it….lol

 

[lund]

Did you put the smooth side out?

I have not yet mounted the panels. This was one of my main questions that is unresolved: which side to use facing out ? I have 1/2" Wherehauser OSB panels that I will be stapling on a 2x4 frame with standard 16" stud spacing. One side has a blue coarse mesh painted the other has printing. It is not clear to me if there are any differences between the two sides in terms of smoothness or surface treatment (say for water repellancy) that might impact adhesion of paints or fillers (say light drywall mud skim coat).

Does anyone know if there is a difference in these 2024 panel sides?

Edit: I did a quick look online and it was unclear to me from the Wherehauser web site if there is any asymmetric surface coating (one side or other). On the material safety sheet, I saw reference to "Paraffin or Emulsified Wax 3" and that might be what is used for some protection in case it is hit by light rain on construction sites. Is that both sides, or just the grid line side?

 

[NUTTSGT]

To be honest a little bit, I was too sorry to top coat it….lol

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.

 

[Sumboodie]

Depending on how many panels you need, an option might be to use Smartside panels instead of OSB. I went this route in my garage. It was about triple the price per panel over OSB, but so much less work than drywall. The panels overlap at the edges for a seamless look, and on the ceiling, I used 1x4's to cover the **** seams. I checked with the manufacturer, and the panels are low VOC and safe for indoor use.

Isn't that just T-111?

 

[Sumboodie]

My interior is OSB. No complaints aside from it's hard to clean, like in the bathroom.
Probably going to do a cover if drywall on those walls to church it up.

 

[Steve W.]

I have not yet mounted the panels. This was one of my main questions that is unresolved: which side to use facing out ?

When I did mine, I put the smooth side out. Can't honestly remember if that was the side with the lines or some light lettering, though.

There were a couple of smaller pieces (angled cut-offs from the other side of the room) that I installed rough side out. The panels are in the stairway to the second floor, so not as visible, but what I remember about them is that it took at least one more coat of primer/paint to hide the lines.

.

 

[Youngandfree]

I have not yet mounted the panels. This was one of my main questions that is unresolved: which side to use facing out ? I have 1/2" Wherehauser OSB panels that I will be stapling on a 2x4 frame with standard 16" stud spacing. One side has a blue coarse mesh painted the other has printing. It is not clear to me if there are any differences between the two sides in terms of smoothness or surface treatment (say for water repellancy) that might impact adhesion of paints or fillers (say light drywall mud skim coat).

Does anyone know if there is a difference in these 2024 panel sides?

Edit: I did a quick look online and it was unclear to me from the Wherehauser web site if there is any asymmetric surface coating (one side or other). On the material safety sheet, I saw reference to "Paraffin or Emulsified Wax 3" and that might be what is used for some protection in case it is hit by light rain on construction sites. Is that both sides, or just the grid line side?

Smooth side should be out. That's the coated side. Rough side isn't coated.

 

[lund]

Smooth side should be out. That's the coated side. Rough side isn't coated.

Thanks.

For the 1/2" Wherehauser brand OSB I have, I did not immediately notice any difference in smoothness that suggested one side was coated (assume light Paraffin or Emulsified Wax) and not the other. I will look more closely when home. I would assume only one side (likely side with the printed grid) would be coated since they want to make them as cheap as possible. Both sides seem simarly smooth at least on a superficial level of inspection.

In my case, I may want to very lightly drywall mud skim coat and then prime and paint the *uncoated* side (rougher or not), since drywall mud filler between strands and paint would likely bond more poorly to the coated side even if lightly sanded. Wax is hard to remove and would likely remain between the bonded strands after a light sanding.

EDIT: I went home and examined more carefully the Wherehauser OSB boards I purchased. Yes, one side is smoother than the other and feels finished. For the Wherehauser OSB, it is the side *opposite* the one with the coarse grid lines. It is enough different where I think I will try to sand and light skim coat the smooth side in spite of the wax. The rain repellent coating is only light. I will probably use one of the off-cuts to test my finish sequence and see how it comes out.

 

[Youngandfree]

Thanks.

For the 1/2" Wherehauser brand OSB I have, I did not immediately notice any difference in smoothness that suggested one side was coated (assume light Paraffin or Emulsified Wax) and not the other. I will look more closely when home. I would assume only one side (likely side with the printed grid) would be coated since they want to make them as cheap as possible. Both sides seem simarly smooth at least on a superficial level of inspection.

In my case, I may want to very lightly drywall mud skim coat and then prime and paint the *uncoated* side (rougher or not), since drywall mud filler between strands and paint would likely bond more poorly to the coated side even if lightly sanded. Wax is hard to remove and would likely remain between the bonded strands after a light sanding.

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.