What screw length do you use for 3/4 plywood walls?

[Matt Neil]

I'm wondering what size screws you use to put up 3/4 plywood wall sheathing? I've been using 1 1/2" but started second guessing myself if I should use 2". But then 1 1/4" in the stud seems excessive.

Also, what spacing do you use? Again, I was using about 18" between screws. 3/4 plywood doesn't have the flex that drywall does, so it seemed excessive to use the same number in plywood that I would in drywall.

Anybody else think through this or did you just start screwing things down without thought?

[Jim O'Dell]

I would probably use the 1 5/8" deck screws that I always have on hand. That is what I used on 7/16 OSB to studs in my shop also. I've never had an issue. Jim.

[Lee Schierer]

Screws should be sized so that the piece being attached has mostly shank and no threads in it. I would use #8 x 1-1/2 screws. That gives you at least 3/4" of thread into the studs. A 1-1/4" screw only gives you 1/2" of thread into the stud, which is not enough for a good grip. In 3/4" material you would want to have the screw shank only into the plywood so that the wood is pulled tight to the stud. A 1/1/4" screw would have a shorter shank (probably 1/2" long) and leave too much tread in the plywood and may not pull down tight to the stud.

Drywall requires more screws because it is not a very strong material and a single screw doesn't have much holding power by itself. Plywood is pretty strong so you could use far fewer screws. 16-18" spacing on plywood should work just fine.

[phil harold]

If this is wall sheathing to hold the building together, screws are not recomended and you need to nail 8d (0.131" x 2½") 6" o.c. on the edges 12" o.c. in the field for areas where the wind speed is less than 100 mph
screws will break before nails will under shear forces

[Matt Neil]

Thanks guys. It's the interior surface I'm working on, not exterior sheathing holding things together. I'll check some areas to see if I'm getting beyond 18" spacing, but I feel better about continuing with #8 1 1/2 or 1 5/8" screws.

[Don Jarvie]

I went over kill and used 2 1/2 deck screws with the sq head. It will never come down!

[Larry Whitlow]

I'm curious why you would use 3/4 ply as interior sheathing? Did you get a good buy or is there some other reason?

[Matt Neil]

I wanted to use 3/4" material for ease of attaching other items to it. And I don't like the look of OSB. Drywall is too easily damaged. I ended up buying prefinished plywood so I don't have to do anything to it. We'll see how it looks when done. I've never used the prefinished stuff and look forward to trying it out on some projects too. $44 a sheet isn't necessarily cheap, but it isn't outrageous either. If I'm buying it once and have to look at it for many years, I want it to be appealing.

[Michael W. Clark]

Post some pictures when you are finished.

I used OSB, but attached it with construction adhesive and 16 ga finish nails. Anything heavy gets attached to the studs anyway (cabinets, lumber rack, cleats, etc.). I've pulled up flooring before that had construction adhesive under it, usually the flooring tears up and leaves chunks in the adhesive. Just an idea if you are going with a sleek look and wanted to avoid all those screws and holes. If you are doing a cleat system (highly recommended) you want to run those screws into the studs anyway.

If you use too long of a screw, you could hit a wire or plumbing in the stud if it is present.

Mike

[David G Baker]

$44 a sheet is a lot more that the under $7.00 a sheet that I paid for 7/16" OSB. It may not be pretty but it works for me.

[Charles Wiggins]

I would probably use the 1 5/8" deck screws that I always have on hand. That is what I used on 7/16 OSB to studs in my shop also. I've never had an issue. Jim.

Ditto for me.

[johnny means]

I was taught to size screws as to not risk hitting wires or plumbing that may be run through the studs. Off course, if no mechanics are run through the wall it doesn't matter.

[Larry Whitlow]

I wanted to use 3/4" material for ease of attaching other items to it. And I don't like the look of OSB. Drywall is too easily damaged. I ended up buying prefinished plywood so I don't have to do anything to it. We'll see how it looks when done. I've never used the prefinished stuff and look forward to trying it out on some projects too. $44 a sheet isn't necessarily cheap, but it isn't outrageous either. If I'm buying it once and have to look at it for many years, I want it to be appealing.

Yes, please post some pic's. I imagine this will be a great looking wall covering for a shop.

[Matt Neil]

I'll post some pics to show what it looks like, but I'm afraid everyone will need to be patient. This whole thing has been slow going as I'm working on it myself with my wife when four hands are needed. We have young triplets so finding time for just me can be problematic but for the two of us, that gets even harder.

I'd never knock someone for using $6 osb. I have the luxury of not building pieces for others and trying to maximize profit. It's pure hobby and I plan on living on the farmstead for 30 more years. By doing things myself, I've found that progress is slow enough that I can afford to pay more for each aspect along the way. BTW, I did just pass my rough-in electrical inspection a couple weeks ago. Getting quotes on spray foam now. Before I get comments to insulate before putting up ply, I have a divider wall that I'm placing the ply on one siden so the foam has a surface to be sprayed against.

[Jeff Monson]

Interesting on using prfinished ply. for interior walls, are you using maple plywood? That should look really nice, are you using a zinc color screw? One would think a black sheetrock screw against light color plywood wood stand out like a sore thumb.