Plywood Ceiling - 24" OC

[bradjacob]

Hi Everyone.

I'm new to the forum and wanted to say hello and mention my project. I'm doing normal framing of the walls in my pole barn (24'x50'). My ceiling joists are 24" OC and I wanted to use 5/8" CDX. The ceiling is simply just covering the bottom of the trusses and no weight will be above it. The trusses will have batting insulation.

I've done some searching and there seems to be many debates on this topic but there was a lot of discussion on the sagging and seams opening due to weight from on top.

My basic question is just simply if over time, with it being climate-controlled, would 5/8" CDX on 24" OC, get any sagging?

I'll post pictures soon, of the progress and journey.

Thanks everyone - and glad to be a part of such a great community!

 

[b-boy]

My pole barn is 30x40. I used corrugated metal on my ceiling. My joists were 24" OC. I used strapping to hold the insulation in place, then put the metal over that and attached with metal roofing screws. I haven't seen any sagging after 4years, and I think the metal would sag more than the CDX. I think the strapping works well to keep the insulation in place.

 

[jack stand]

Metal is a very popular and economical choice for a ceiling as it's 100% finished (painted) when you install it. Just to be sure, you can staple up some poly before you do your 5/8 plywood which will be fine.
Welcome to the forum!
Remember that you'll be making at least 3 "trips" across your pw ceiling. Installation, priming, then finishing coat. A lot of guys will prime before installing but that's a shuffling chore also.

 

[Tbender78]

IMHO 5/8 is overkill for a ceiling. If you backed up the joints the gap shouldn’t be noticeable.

 

[mike93lx]

I think it should be just fine. 5/8 is quite thick.

I'd be inclined to run purlins perpendicular and then use much thinner sheathing to ease handling.

I would prime and paint everything before hanging

 

[Sumboodie]

5/8" drywall is most commonly hung on 24" OC trusses, with 2+ ft of insulation.
I can't imagine plywood performing worse.

 

[bradjacob]

Thanks guys, appreciate the advice. I (may) go with 1/2 or stay with 5/8. Either way, I'll be using a hoist and it'll be a bit of a slo-go... But steady wins the race

 

[Dig Doug]

You can block in between the joists so the 2 sheets float together

hang one row of plywood
then take the block center it above on the hung sheet screw it to the hung sheet and bridge the gap between the joists
use 3 or 4 screws per block / bay move onto the next bay

hang the next row of plywood & repeat

this will keep the edges flat and marry the seams together

 

[The Cobbler]

I wouldn't use anything over 3/8 probably. scab a pc along the edges so you can screw the panels them .

 

[dmittz]

5/8 plywood will deinietly not sag. I put 3/8 on my ceiling with 24in OC trusses in my shop and it has not sagged at all.

 

[PassnThru]

I put 7/16 OSB on my ceiling with 24 on center joists. There has been no sagging at all.

 

[Innovate1]

I recently saw the inside of the house I grew up in. Near the coast of Oregon so in the middle of timber country. Wood was plentiful so no drywall in the house. All the interior was plywood. Guessing the ceiling was 1/2". You could see the seams of the panels. Not sagging but just movement over the years but this was in a room addition done about 55 years ago. Hard to avoid a bit of movement over the years. I went with ribbed metal in my detached garage recently and very pleased with it. If I was doing plywood I would use 7/16 - plenty to avoid sag with nothing above but insulation. Putting a scrap of wood halfway between the trusses screwed to each panel will help with any panel warp and keep things nicely lined up but not really required.