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Painting OSB

Dave_Curry_'s picture

Just ran into a strange situation.
I am putting up 7/16 OSB as the ceiling in my 45x24 barn (16 ft) high ceiling. Want to paint the ceiling white to brighten it up as much as
Pre painted one batch of boards with whatever primer we had around, It
truned out to be the good stuff Kilz Oil based. Second coat of Latex came out fine.
Working on the second batch today, not using any primer, just a Latex ceiling paint and noticed some of the chips in the OSB are lifting up?
Could this be due to the water based nature of the Latex paint?
Would it help to paint the rough side of the OSB instead?

Has anyone seen this before?

(post #88960, reply #1 of 7)

Maybe you got a bad batch of OSB.

(post #88960, reply #2 of 7)

ok.I must have a slow learning curve. I'll try this one more time...

hi dave- that horrid osb board will always flake up with moisture, the nature of the beast. but being in the barn out of the main weather it will do what you want to brighten up by light reflection, depending on how moist the barn stays with condensation. it would take alot to destroy the integrity of the board. the best is an oil primer followed by an oil topcoat to seal it up. I haven't experimented with rough side vrs gloss side since the oilpaint on the smooth side always gave a nice surface look. You might want to call a osb manufacturer for their recommendation but it seems I recall the osb manufactures don't recommend painting osb, I think it's just a legal disclaimer thing. plenty of osb outbuildings out there still surviving with nothing but a coat of latex protecting them. unfortunately after a year or two they really look it. the extra cost for oil paint is a small price to pay for security, but then again so is a little more cost for plywood.

(post #88960, reply #3 of 7)

As always, the key to a good paint job is the primer. Always use primer on bare sufaces. Yes, it seems that OSB spends all its time absorbing water and for that reason I don't really care for it. But it is inexpensive and primed/painted with oil should last awhile(?).

(post #88960, reply #4 of 7)

Rez and Ken, Seems likes we are all on the same wavelength.
Just got back from the paint store with an oil based primer.

Looking at the sheets that had the lifting, it seemed to happen
where the Latex was rolled on the thickest. Most water.

I'm not real excited about OSB either but at $5.00 a sheet it's
almost as cheap as sheetrock and I don't have to tape and joint over
my head!!

I think the painted finish on the smooth side will look alot like
textured plaster finish. Rez from your post you seem to indicate you
have seen this done. What finish did they use over the seams?

I am thinking, about battens on a 4' by 4' grid over the seams. But
what to use for the battens that is cheap? could spend a half a day on the table saw and make up 1 1/2 by 3/8 pieces out of two by stock
any other alternatives?

Thanks again for the help.

(post #88960, reply #5 of 7)

Dave- You could go out and buy a few bundles of lath. Not esp. pretty but cheap. Maybe try to find some that hasn't been sitting out in the rain.

(post #88960, reply #6 of 7)

b Another home owner. One day we will rule the world.

Ya Dave, cover those seems with a batten. Sounds like you got a nice barn if your concerned about exposed seams at 16 ft. This past summer I did a retro for a women of a storage shed that had the dreaded osb that hadn't been painted in a long time and know what happens. Instead of a tear of of the walls and replacement I elected to cover over with new osb and caulked the seams then battens. Had to caulk every little pocket of possible moisture catch then the topcoats, trim boards and base skirt caulked also. If I had to do it again I'd opt for a little added expense with T1-11 or at least plywood to lessen the labor load necessary for a reliable finish. I had a pile of half inch 8ft lengths of 2x stock from the neighborhood garage door factory castoffs so my labor was nigh unto nil there but really once you set up and start ripping your battens out of the 2x4s it'll go pretty fast even with the size of your ceiling it's just the thought of it that makes one search for a quicker way without spending more bucks on the barn. Maybe just encircle your perimeters of the 4x8 sheets first and see if you want the added labor of the 4x4 panel. After rereading your post I see that your term 'barn' doesn't necessarily imply cows. Guess I still got alot of rural american in me. I think now you are speaking of workshop/polebarn which puts a new view on things. Any latex on top of the primer will work just prioritize complete coverage with the oilbase primer as your sealer cause you can repaint the ceiling at will if necessary to cover yellowing, smoke discolation or any host of problems requiring the refreshing later on. So your attention to seams is more of a cosmetic decoration as opposed to structure concerns. Battens are the way to go I think and depending on your desire for the final look then you could...gulp...caulk the batten seams to get rid of the nasty black lines. Ha! And we were concerned over labor ripping battens out of 2x stock. It's the old 'spend a dime to save a nickle' and 'how good do you really want it done scenerio'. Now it's down to how much labor you want to put into this project. It'll probably look ok regardless of how far you decide to go. Best to ya.

(post #88960, reply #7 of 7)

if you guy's check the LP OSB website, they actually advertise OSB as a paintable hoarding material, guess they have never used it then, huh, will they ever tell the truth.

good stuff