Come hell or high water this year I’m sheathing my garage walls inside and installing a wall A/C unit. I’m thinking 1/2” plywood I just don’t know what grade of plywood I should use. Does the number of ply’s make a difference? The walls are insulated and the plywood will be painted. Any suggestions before I get into this?

Sanded one side. AC iirc. It will probably be a 4ply. I would not go less. Some times at smaller lumber yards you can get a 5 ply 5/8" that is almost the same price. I forget what they call it. But when produced if has a minor defect so they cannot sell it as a graded product. Still very good. They buy it in full units. If you can find it it would be perfect for your situation and give you a far superior product.

I used plywood in my shop years ago. Never painted it. Still looks great and is perfect for my liking. Good luck.

This message has been edited. Last edited by: old rugged cross,

ACX I believe is the grade you want. Sanded on one side - flaws on the other. Place sanded side facing out.

1/2 or 5/8 will probably be good enough. Should allow you to screw directly into it for general usage.

If you know you have one wall or two that will have some particularly heavy stuff mounted - consider 3/4 plywood for those areas.

Though for even the heavy stuff, you could probably get by with 5/8 and french cleats. Or double up an additional section of plywood screwed (grk or spax construction screws) across multiple studs to beef up that area. Thicker plywood just gives you more pullout resistance outside of the studs - or just screw into studs for that section without doubling the plywood.

Maybe mark your stud location for future reference with just some subtle marks at the top or bottom of the walls for quick reference.

Wouldn't sheetrock be a whole lot cheaper, and a better looking finish?

If it were my garage I would consider this wallboard:

https://trusscore.com/


It is a corrugated drywall replacement.
It is not cheap but a great product for a garage.

Oak sanded 1/2 plywood is $29 a board at Lowes, there are less expensive options but they are not sanded/finished.

Sheetrock runs from $20 a sheet for top of the line mold/mildew resistant to $12 a sheet for normal residential sheetrock.

Could put up some plywood where you want to put in hangers, cabinets, work bench and sheetrock where you just want to insulate and close up the walls.

Yeah, if you want to upgrade to something more ready for use on some walls, look into the wallboard that is slotted for shelves, hangers, etc.

quote:

Originally posted by Georgeair:
Wouldn't sheetrock be a whole lot cheaper, and a better looking finish?

This would be my professional recommendation for several reasons….

First it is fire rated. If your garage is connected to your home this is a code requirement. Typically 5/8” drywall is required on the party wall and ceiling although most drywall contractors will use 5/8” throughout. If the garage is not connected you could use 1/2” to save a bit. 5/8” has a one hour fire rating and 1/2” has a 1/2 hour rating.

Secondly, you will get a much better (i.e.) more professional result if done properly.

You typically don’t need the mold resistant board in a garage setting. It is primarily used in bathrooms that can have very high humidity.

I don't know what prices are now but when I build my garage in 2002 I used 5/8" OSB for ceiling and walls. Reasons being almost all the wall area would be covered and because plywood was *much* more expensive. The ceiling was primed then painted white for light reflection. The walls received one coat of a mix of all my part cans of varnish along with a couple gallons purchased. Plywood will make a nicer painted wall if much is visible.

Edit to add: it's a separate structure from my house and with 50+ gallons in multiple cans, of diesel, gasoline, oil, used oil, etc. the combustibility of the wall sheathing doesn't matter.

quote:

Originally posted by ridewv:
I don't know what prices are now but when I build my garage in 2002 I used 5/8" OSB for ceiling and walls. Reasons being almost all the wall area would be covered and because plywood was *much* more expensive. The ceiling was primed then painted white for light reflection. The walls received one coat of a mix of all my part cans of varnish along with a couple gallons purchased. Plywood will make a nicer painted wall if much is visible.

Edit to add: it's a separate structure from my house and with 50+ gallons in multiple cans, of diesel, gasoline, oil, used oil, etc. the combustibility of the wall sheathing doesn't matter.

I did mine very similarly 7 years ago when I built it.

Drywall and OSB are out for my own reasons. Sounds like ACX is what I’m looking for. Old Rugged Cross let me know if you remember the name of the 5/8” 5 ply. I’m on a slab so all my tools have to be in the garage, that means I have to have my walls loaded with shelves.

What do you mean by sheathing?

Sheathing is the exterior layer of a wall or roof and is a structural element of the wall or roof.

Finishing is what you do to the interior of the wall.

Yes the interior trapper

I used white pegboard for my finishing. Stapled insulation in place first, then screwed the pegboard to the studs. No need to paint. No question that I can hang stuff on hooks, anywhere.

quote:

Originally posted by 400m:
Come hell or high water this year I’m sheathing my garage walls inside and installing a wall A/C unit. I’m thinking 1/2” plywood I just don’t know what grade of plywood I should use. Does the number of ply’s make a difference? The walls are insulated and the plywood will be painted. Any suggestions before I get into this?

I'd be concerned about the fire load, especially as its in a garage. It's likely not "code" and is something that could come into play upon resale if that is a consideration.

[/QUOTE]

I'd be concerned about the fire load, especially as its in a garage. It's likely not "code" and is something that could come into play upon resale if that is a consideration.[/QUOTE]

My insurance guy wasn't happy with wood.

I would put up plywood in areas where you will hang tools, cabinets, bikes, etc. Then I would use 5/8" drywall everywhere. So some areas get plywood plus drywall.

I’d use drywall as well and hang slot board over the drywall in areas I wanted to hang tools. Alternatively, I’d nail 2x4 pieces between the studs in areas I might want to install tool hangers then drywall.

I’d build free standing shelves for tote bins and only anchor them to the wall to prevent them from tipping. Most of my power tools came with nice cases and those would go on the free standing shelves as well unless, I was worried about theft/borrowing, in which case; they’d go into a locking metal cabinet or rolling tool box. The cabinet would be anchor and tool box chained to the floor.

consider tongue & groove. That's the only regret I have with the 1/2" OSB I have in my shop - the seams don't always sit flush. It's a shop, but I was up close & personal with each sheet, so I notice.
Shop has purlins instead of studs, the bathroom/compressor room looks nicer where I could keep the seams tighter & screw to a stud.
I think I paid $8 a 4x10 sheet in Jan 2020. Neighbor paid ~35 a sheet 6 months later.

Just to finish this thread off, I wound up using a 4 ply, 15/32 RTD plywood and painted it with a satin white paint. I was never looking for beauty just functionality and I’m plenty happy with the results. The A/C unit will have to wait until spring. I’ll be looking at Friedrich through wall units that have A/C as well as electric heat. Since I finished the walls so late in the year, I’m buying a new snowblower.