Will 3/8 plywood sag on a ceiling?

[summit151]

Hello i am about to install plywood on the walls and the ceiling in my new shop. I have purchased 3/8 plywood already and the trusses are 24 inches on center. I am wondering if the plywood will sag? I will also be blowing insulation in

Thanks

 

[SD396]

I'm pretty sure my ceiling is 3/8" ply on 24" centers and there is no sagging. House was built in '74. Walls I would go 5/8" or 3/4" for durability plus you can hang things anywhere you want without having to hit a stud.

 

[boobag]

only way it may sag, is if you have a lot of moisture or it gets wet a lot. but even then, it wouldnt sag much.

 

[Morrisman]

I was planning the same thing but with 1/4" play, and bigger spacing. The thinner it is, the lighter it is, and it will only be to keep dust/air at bay, and provide a little insulation.

I also planned to screw 2" x 3/8" battens across to cover the joins, and also provide some support. Maybe paint them a contrasting colour, to fancy it up a bit.

 

[buzz4041]

I'm on 16" centers for the ceiling and used 1'4" with no sag and insulated on top. On the walls I went with 1/2" for being able to hang something anywhere I want and it works well.

 

[lakeroadster]

I used 3/8" T-111 in my shop, walls and ceiling. No sagging issues.

 

[toplessHO]

panel adhesive also helps and use screws instead of nails

 

[Cyberbear]

It looks like most journal members are happy with 3/8" over head ply at 24" center spacing, but I'm a little leery about that, especially with the insulation weight and if you ever get a roof leak and the insulation becomes water logged, the ply may well sag. I suppose it depends on the quality of the plywood you are using.

 

[ADSR]

There can't be much diff in price between 3/8 and 1/2. Take it back and go for the 1/2.

 

[Thorold]

Very interesting. I'm wondering, totally from a cost standpoint, if OSB would be an option.

 

[ADSR]

Very interesting. I'm wondering, totally from a cost standpoint, if OSB would be an option.

Been roof sheeting new construction at 24" OC with OSB for years. You have to use an aluminum H-clip between trusses. Works well. 7/16 OSB will be fine inside used like drywall.

 

[diypolebarns]

Be certain you utilize plywood and not OSB. Plywood is inherently stronger than OSB. 3/8" will work, but if you are planning on blowing cellulose insulation in your ceiling you will want to move to 7/16" OSB or either 1/2" plywood or OSB. It is also best to use a plastic vapor barrier above your ceiling and be certain the attic space is well ventilated. This will keep the moisture issue in check.

 

[charlie v]

Be certain you utilize plywood and not OSB. Plywood is inherently stronger than OSB. 3/8" will work, but if you are planning on blowing cellulose insulation in your ceiling you will want to move to 7/16" OSB or either 1/2" plywood or OSB. It is also best to use a plastic vapor barrier above your ceiling and be certain the attic space is well ventilated. This will keep the moisture issue in check.

+1 on that

 

[Blk88GT]

I did 1/2" with 24" center trusses and R50 insulation. No sagging here.