# Garage Drywall



## JA Boomer (Sep 25, 2014)

Getting ready to drywall the garage. It is a double (over-sized) detached garage about 26 feet wide by 23 deep with a single double rolling door. Has an old Reznor gas heater in it.

Live in Calgary, AB. It was built in 1968 but unfinished, I have ripped it down to the studs and am bringing it back to life. New siding, electrical, and insulation already done. Just finishing the vapour barrier.

Now on to drywall, I'm getting different opinions from different people. A neighbour who's in the trades and knows his stuffs says he always uses 5/8" drywall on exterior walls (which they all are in a garage). But two other friends with experience drywall'ing have told me I shouldn't have a problem with sagging if I use 1/2" drywall on the ceiling even though I have 24 OC rafters. I have R40 in the attic (about 14" of fiberglass) and all of my electrical boxes were setup for 1/2" drywall.

I was planning to put a piece of fire-rated drywall above the gas heater, and was originally thinking of finding 1/2" sag-resistant drywall for the rest of the ceiling. *My current thinking is that for the limited extra cost I will just do the whole garage in 5/8" fire-rated drywall and live with the 1/8-1/4" recess that will create for the electrical boxes.*

What's the consensus on here for drywall regarding:

-1/2" vs 5/8" on ceiling and/or walls
-sagging really a problem with 1/2"
-Is 5/8" more sag resistant and sag-resistant 1/2"
-fire-rated above drywall above heater or everywhere
-possible problem with electrical boxes being recessed
-any reason to use moisture resistant drywall for garage application

Appreciate anyone's insight.

Thanks, Boomer


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## Ron6519 (Mar 28, 2007)

You don't mention the clearances to the heater.


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## joed (Mar 13, 2005)

With 24" center my vote would be for 5/8" drywall.


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## JA Boomer (Sep 25, 2014)

Ron6519 said:


> You don't mention the clearances to the heater.


Good point. I have the old manual. I think it said all sides of the heater must be 6" from combustibles. Because the gas line is already piped in, I would need a gas fitter if I wanted to lower it, so I just reinforced the hanging supports and left it at the same elevation, which will be 4.5 - 5" from the ceiling drywall. I've been monitoring the vapour barrier above the heater since I turned it back on, and it never gets hot enough to concern me.


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## rjniles (Feb 5, 2007)

It the garage attached or detached?


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## JA Boomer (Sep 25, 2014)

rjniles said:


> It the garage attached or detached?


Detached.


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## Californiadecks (Aug 30, 2012)

You may want to consider any jamb width that was sized for 1/2". Doors, windows etc.


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## JA Boomer (Sep 25, 2014)

Californiadecks said:


> You may want to consider any jamb width that was sized for 1/2". Doors, windows etc.


Ya I think I'm good there. My windows are kinda in between and the door is way too big, almost an inch I think, so I'll have to do some specially notching there no matter what.


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## ToolSeeker (Sep 19, 2012)

With the building being heated and the walls insulated 1/2" should be fine for the walls. But I would defiantly use 5/8 on the lid especially if your 1/2 is the lightweight junk. If you use 5/8 on the walls your boxes won't be a problem they make extenders that will make up the difference.


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## ddawg16 (Aug 15, 2011)

I'd do 5/8" all around. Especially for the ceiling....1/2" will start to sag with 24" OC rafters.

Do the ceiling first.....then walls.

The advantage of 5/8" over 1/2" in the garage....it's a bit stronger and will tolerate the abuse garage walls can get.

Before you put up the drywall, take plenty of pics. In some cases, I've put a tape measure down when I took a pic so I could see exactly where each stud was....this is handy when not everything is on 16" OC.

Do your walls go all the way to the floor? If so, I saw one suggestion where a guy put down a 1x6 board made of that composite decking material. He put silicone on the bottom edge and the drywall sat on top. That way he didn't have to worry about the bottom edge getting wet. And to be honest, it looked really good in the one pic I saw. Kinda like a baseboard....but more practical

For paint....I'd do a good coat of primer....and then follow up with exterior semi or high gloss paint. The semi or high gloss covering attracts less dust (like saw dust), easier to clean....and water won't bother it.

This is my garage....before I filled it with stuff


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## Tony_G (Dec 10, 2015)

ddawg16 said:


> This is my garage....before I filled it with stuff


Looks good, did you do anything to the floor?


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## ddawg16 (Aug 15, 2011)

Tony_G said:


> Looks good, did you do anything to the floor?


Tossed a couple gallons of concrete sealer on the floor.

Paint and oil wipes right up.

Downside....sawdust makes the floor slippery


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## ZZZZZ (Oct 1, 2014)

Cool. Never seen a spiral staircase in a garage.


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## Gary in WA (Mar 11, 2009)

IMO, add a bollard in front for that oops moment, or at least wheel block stop...probably do more damage to the vehicle, lol. Hope you have weather-tight sealed doors at top landing if living space above.

Back to the original poster before the advertisement; use 5/8" as the 24" span may be a problem when the drywall is damp from weather/interior moisture from gas heater soaking the drywall because of the vapor barrier. If the heat was continuous, no problem, it could dry out.

Gary


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