OSB on Ceiling - To Strap or Not to Strap

[babzog]

That is my connundrum. I'll be using 7/16 OSB (cheaper than drywall) to finish the ceiling in the shop. Trusses are 24" OC. Will I get sag if I don't strap it to 16" OC?

 

[Call me the Breeze]

I did OSB on my shop ceiling, but I believe it was 7/16". My Trusses are 4' on center. I had to put in 2x4's between the trusses so I had something to fasten the edges of the OSB to. I hadn't thought of doing it, but After I got the first row done, I went to put up the adjacent row and it already wasn't even. Some were bowed up a bit, and some were bowed down. So I cut the 2x4's and tied them into the trusses, stapled and screwed the 8' long edges to them, and that straightened them out. If I were to do it over, I might have put another set of 2x4's in the middle of the 4x8 sheet just for extra support. I noticed there is a slight sag in the middle on a couple of the sheets but it's hardly noticable. I borrowed a staple gun from work that worked wonderful for putting up the sheets. I put up almost all of the 27 sheets by myself. It was a chore but it came out good. I didn't have the money to rent a panel lift, and cause I was doing it little by little at night after work, I would have had to rent it for a week. I made a 4' long jig that I screwed into the truss that would hold the sheet up on the one end, then I would lift the other end up, and use those quick bar clamps to hold it, while I stapled it up. I then went back around with some screws to make sure it wouldn't pull out over time. I wish I had 14 foot tall ceilings, but the 8 foot tall one I do have, made this job easier. I would recommend 3 people to do it though, 2 to hold it up and one to go around screwing it up, as opposed to trying to balance the one edge on your head while trying to reach the dang clamp that wasn't in the right place. And yes I dropped a couple of sheets in the process, and the corners break real easy

 

[vettezx-6]

I did exactly that when I finished the inside of my two car garage about 3 years ago. Drywall screwed it into the joists, 24" centers. Hasn't started to sag or bow at all at this point. Oh yeah, I blew insulation above and that doesn't seem to have affected it either.

 

[dlc]

24" center with 7/16" OSB here. No sagging 3 years later.

 

[JCByrd24]

Agreed, should be fine without sagging. The hardest thing is hitting the 1-1/2" edges. When I drywalled instead of strapping the whole thing I just cut a bunch of 8' strapping in half. It worked out that my first sheet always overlapped a truss by a couple inches so I put the sheet up right to the trusses in full length and stuck a 4' piece of strapping up above the short edge of the sheet afterward. Screwed it to the last sheet hung, then the next sheet could land on it. About twice the screw area to hit over trying to land on the trusses, plus the trusses aren't always perfect.

 

[babzog]

^^ I like that... saves cutting all but the last sheet.

Happy to hear positive things about not strapping and no ill effects.

I noticed today (when I was checking the mouse traps) that I made a small booboo when I started insulating the ceiling... I forgot to put a nailer strip at the top of the wall that's parallel to the trusses. I'm only two rows in so I could pull out the row and add the strip (or pieces of strip, since there's wire run along there and going down into the wall), but I'm also thinking, "This is a shop, the OSB on the wall will support the ceiling and I'm probably not going to stand nr the door and poke the ceiling where it meets the wall".

 

[grcthird]

7/16 osb on 24" center should not sag, but I would cut it so the joints break on the trusses. You may have to scab a short 4' length of 2x4 to a truss every once in a while but it's the right way to do it. Stagger your joints so don't have a 4 way intersection in your ceiling. And post finished pics.

 

[skeletonizer]

I scabbed in 2x4 so that I could screw every foot around the edge of a sheet. The sheets run across the trusses (2' centers) and no sagging after a year. I used Kilz and semi gloss ceiling paint on it.

 

[Gary S]

My roof is 7/16" OSB with 3000# of shingles on top of it. It is on 24" rafters and the OSB doesn't sag, so I can't believe you could get any sag with the OSB unloaded inside.

 

[nate379]

Will be fine. The ceiling in my Dad first garage is OSB and we built that one in 1990-1991. I think he did use 1/2" or 5/8" though. He happens to work at an OSB mill so when "Code" says 1/2" that meant he used 3/4"