Sealing OSB walls

[smk17]

I should have known to come here first instead of scouring the web for answers.
New garage, I used 7/16 OSB for the walls, 1400sq feet. I talked myself out of painting the walls but I do want to seal them with polyurethane or something.
1. Spray or roller?
2. Water-based or oil-based?
3. Do I even need to seal it?
4. Is polyurethane okay to choose for OSB?

I've never used a sprayer.

Thanks

 

[jack stand]

Iirc you'll end up painting it twice anyway so you might as well use a primer/speaker (kills for instance) with the presumption that it's less expensive than your finish coat.
HD does have a good one coat that I've used on bare rough sawn lumber that might do it in 1 coat. "Behr Deck plus solid color waretproofing deck stain". (I'm reading my gallon can)
It's paint to me, thick and creamy. Nothing like a "stain" that I've ever seen, but I'd question how it covered the smooth side of OSB. The rough side, no problem.

 

[Steve W.]

On most of my walls, I used one coat of primer and one coat of gloss white paint. There were a few panels that I had to use the back side of the panel facing into the room because of the way previous cuts left the panel. On those, I had to use two coats of primer and maybe two coats of paint, but since they were just a few partial panels, not much extra primer, paint or time.

All went on with a roller.

All was latex-based (water).

I consider the primer to be a sealer.

.

 

[smk17]

Thanks for the replies, I'm not sure if you read my post wrong or are just answering in general, but I do not want to paint it.
I only want to seal it with clear polyurethane or something similar.

 

[jack stand]

Yeah, that's not the way I read it.

 

[smk17]

Yeah, that's not the way I read it.

my bad! lol

 

[WillyBoy]

That looks like a nice space for your hobby's. Even though you've made up your mind, you can still reconsider.
As Steve and Jack mentioned, a coat of white paint will seal the material and more importantly make the space a lot brighter.

When I had a third bay put on the existing two bay garage three years ago, I stripped the original siding and felt paper off what had been the outside end wall. The sheathing was particle board from 1982. I ran the orbital sander over the surface to knock off the roughness and rolled on two coats of Kilz 3. The difference was striking.

 

[smk17]

That looks like a nice space for your hobby's. Even though you've made up your mind, you can still reconsider.
As Steve and Jack mentioned, a coat of white paint will seal the material and more importantly make the space a lot brighter.

When I had a third bay put on the existing two bay garage three years ago, I stripped the original siding and felt paper off what had been the outside end wall. The sheathing was particle board from 1982. I ran the orbital sander over the surface to knock off the roughness and rolled on two coats of Kilz 3. The difference was striking.

I know, I have gone back and forth quite a few times on painting it or just sealing it. The final reason I chose not to paint it is it's just not gonna look great, it'll look like a bad paint job no matter how hard I try, and it will cost only "aesthetic money" as I call it. And it's just a garage, lol. I dont need it to look like a showroom.

And thanks! I love it so far, can't wait to start building stuff

 

[jack stand]

Smk17 I'd bet that you'd appreciate the brightness a light paint will give you and "sealing" makes me think along the lines of a shelack or varnish. OSB is pretty "sealed" by the glues/resins and whatever they add to it and I'm not sure how much sealing is possible or how much of a "layer" is possible to leave behind. You might be waisting your money and time.
OSB is (mho) like a pig, you can put lipstick on it and...... you know the thing.
I'd keep researching online or maybe at an actual paint store you can get a satisfying answer to what you should use.

 

[pattenp]

If you hung it slick side out what's the purpose of sealing it?

 

[smk17]

If you hung it slick side out what's the purpose of sealing it?

Well that's why I came here, is that slick side of OSB already good enough and sealed? I would love it if that was the case lol

 

[Kaizen]

DO IT! DO IT! DO IT!!!!!! You are already half way there with poly. It only osb so bad technique won't show. I also wanted to keep dust out of the cranny's.

 

[Stelzer]

Gardz makes an effective clear sealer, is simple to apply, and goes on very easy. If you want something that would both seal as well as protect, Corotech V027 would be my choice.

 

[Notgrownup]

I rolled Killz on mine and it’s held up well

 

[smk17]

DO IT! DO IT! DO IT!!!!!! You are already half way there with poly. It only osb so bad technique won't show. I also wanted to keep dust out of the cranny's.

But, that's not OSB

 

[smk17]

I rolled Killz on mine and it’s held up well

Thank you, was it Kilz Klear?

 

[lolaetype]

If the OSB absorbs polyurethane like the MDF I used for a workbench top you are probably going to need at least a couple of gallons.

 

[Kaizen]

But, that's not OSB

potato potatoe. Both compressed wood product. That was the good old days before the pandemic. You deserve some color in your life

 

[NUTTSGT]

I rolled Killz on mine and it’s held up well

Oil based ? Did you topcoat ? If you don't top coat it, it will slowly yellow. Probably slow enough you won't notice.


Plain OSB or plywood can look nice but painting it white will brighten the space up a lot.

 

[jack stand]

Well that's why I came here, is that slick side of OSB already good enough and sealed? I would love it if that was the case lol

The only time I've seen it get "flakey" is being outside with repeated wetting. Your good to go!

 

[Notgrownup]

White Kilz, I don’t remember if it was oil based or water based.. I wanted the room bright, I never topcoated it yet.

 

[smk17]

Update: Apparently sealing interior OSB boards with something clear is just not that normal, or people just don't bother with it, I truly couldn't find a definitive answer on Google, it seems most people paint it, or I simply overthink everything...lol

I went to Lowes on Friday and the young kid there working at the paint area looked at me like I stepped off a UFO hovering in the parking lot. Pointed me sheepishly toward deck sealant , Thompson's water seal. I thought that would probably be overkill as it's not gonna be raining in my garage. My next stop at Home Depot, the young kid that was usually in lumber had been put in the paint area and didn't help.

Then I went back to Lowes on Saturday for something else and noticed a new guy in the paint area, an older guy, so I asked him. With a combination of being tired of looking, and believing this guy knew what he was talking about, he led me toward "Valspar, one-coat exterior sealer clear, water-based."

Probably the same thing as Thompson's water seal, but I didn't care anymore.

Bought 5 gallons, $189.00.

Got home, set up my roller and extension pole, poured some in the pan and started rolling. It wasn't like paint that's for sure, it ran down the walls so fast it felt like I was painting with water. But I got the hang of it, had plastic down so it didn't slop all over the concrete floor. Garage walls are done, and I'm quite happy with it.

The sealant didn't distort the OSB or cause it to puff up, etc.

Now you all can tell me what a huge mistake it was to choose this product lol!!

Thanks for all that helped out, I truly appreciate it.

 

[jack stand]

Your happy, Lowes is happy, and we're all happy.
What a happy bunch.

 

[dcg9381]

I know, I have gone back and forth quite a few times on painting it or just sealing it. The final reason I chose not to paint it is it's just not gonna look great, it'll look like a bad paint job no matter how hard I try, and it will cost only "aesthetic money" as I call it. And it's just a garage, lol. I dont need it to look like a showroom.

I have painted OSB in my shop. No one really thinks it's ugly. It's not "residential quality" but no one notices. You still pick up the texture. OSB will absorb a lot of whatever you put on it. Expect 2 coats.

Do it in clear and it's going to show all the imperfections and seams a lot more. But it's your shop, I ain't gonna complain.



I just did a cargo trailer. The plywood floor was done in polyurea and plywood walls were done in epoxy, both in white... Costs a lot more. Looks better? Not really..

 

[BurtEggley]

clear poly if you want it to look like OSB, or primer and white if you want the garage to be brighter and see the black widow spiders when they make nests.