Garage drywall Question

[john6221]

So here's the deal:

The previous owner of my house did an absolutely terrible job (he used 3/8 drywall on 24'' center joists and sometimes didn't end a piece of drywall on a joist) at drywalling the garage. I've already ripped out the ceiling drywall (he only finished 1/3 of it anyway) and furred down the ceiling on 16'' centers so that I can put up 1/2 drywall.

Now, on to the walls: they are in fairly bad shape over the years due to run-ins with tools, snow-blowers, etc. I had thought about tearing out the old drywall and putting up new, but instead I think I'd like to just go over the drywall with plywood and then paint it white. I've seen that done before so I wouldn't be the first guy to do it. But, the walls are also insulated with fiberglass insulation (probably 2-3'' of kraft-faced) and I was wondering if I should really be leaving that, or tear everything out and start over again. Would you leave the old wall and put plywood over the drywall? Or would you tear out the drywall and insulation, put in new insulation, and then put up plywood?

[Papa bear]

Attached garage or separate building?   If attached, make sure you use 5/8 drywall between garage and living space for firebreak.

Why not repair the drywall?  I would think it would be easier than redoing the entire thing. 


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[john6221]

Attached garage but the drywall between the house and garage is 5/8 and in good condition. I'll be working on an outside wall.

As for repair....it's just too bad of condition. And I like the idea of plywood for hanging things as well. 

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[Papa bear]

Sure.  Then go for it! You could even go fancy and get plywood wainscoting and make it look like you planned it that way.


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[john6221]

I guess my follow-up question would be: is the old fiberglass insulation still doing its job? Should I leave it there or tear everything down to start anew?

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[Papa bear]

If the fiberglass is kraft faced and installed correctly, it should still be fine.  However, With the walls at 24" on center, can you verify the condition of insulation by cutting out a rectangle of drywall?  Something that can easily be screwed back in when you're done.

Do you condition your garage?  I'm not sure you even need to have it insulated in the first place.

It's hard to give good advice without actually seeing and being there. I'm sure my opinion would change if I was on site and knew exactly what you were going to use the space for.




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[john6221]

I don't condition the garage, but I'd like to. It doubles as my woodshop so I'd like to add a gas heater someday to keep it warm in MN winter.

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[john6221]

That's a picture of the ceiling before I tore it down. Notice how he didn't end the drywall seam on a joist and it flopped down nicely over the years.

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[Papa bear]

Ok I may have misread your first post.  I thought the walls of your garage were 24 on center (Assuming the structure was built by previous homeowner and  may have made mistakes elsewhere)   

24 on center trusses are very common. You didn't need to build out for 16.  If you are going to condition the garage, drywall the ceiling back up and blow in new insulation. 

Since you will be heating the garage, spot check behind the drywall on the walls to make sure it is insulated and it hasn't fallen or sagged down.  If it is kraft faced and installed correctly, again, there shouldn't be an issue.  If there is a problem, go ahead and tear out and redo.  It's a lot more time, effort, and cash to redo it.  If the insulation seems ok, just fix the walls cosmetically and get back to your wood shop projects.


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[john6221]

Yeah the ceiling is 24'' joists. I have already furred them down to 16" using 1x3 strips because it allows me to use 1/2" drywall and it was easier than removing 5000 staples from the old Kraft faced insulation.

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[lthenderson]

I used plywood in my previous house and loved it. It is more expensive than drywall but it holds up much better to the abuses a garage sees. You need to get a good sealing primer however before painting to prevent the tannins from leeching through your paint job. One drawback is that my stud detector was rendered useless for finding studs so you have to go off nail heads to figure that kind of thing out.

I personally would tear off the drywall since that is a fairly easy project to do. This will allow you to get into the studs to fix or expand any electrical systems before covering again. I put a lot of electrical outlets in my garages compared to the normal two or three outlets I find in many. Gives me a place to plug in all my tools and battery chargers. Also, if you put plywood over drywall, you either have to put extenders onto all your electrical boxes for any switches or outlets or move the boxes out the thickness of the plywood to get the covers to fit correctly. You wouldn't have to do this assuming you are putting in the same thickness plywood as the prior drywall.

[Metric Mouse]

I used plywood in my previous house and loved it. It is more expensive than drywall but it holds up much better to the abuses a garage sees. You need to get a good sealing primer however before painting to prevent the tannins from leeching through your paint job. One drawback is that my stud detector was rendered useless for finding studs so you have to go off nail heads to figure that kind of thing out.

I personally would tear off the drywall since that is a fairly easy project to do. This will allow you to get into the studs to fix or expand any electrical systems before covering again. I put a lot of electrical outlets in my garages compared to the normal two or three outlets I find in many. Gives me a place to plug in all my tools and battery chargers. Also, if you put plywood over drywall, you either have to put extenders onto all your electrical boxes for any switches or outlets or move the boxes out the thickness of the plywood to get the covers to fit correctly. You wouldn't have to do this assuming you are putting in the same thickness plywood as the prior drywall.

Electrical would be my only concern with plywooding over drywall. A pain in the ass to bump all the outlets out to flush up to the new wall surface, but not the end of the world.

I'd bet the insulation is fine - I wouldn't bother with it unless there is some reason to suspect water infiltration into the walls.

[john6221]

Well, I'm lucky, as there is no electrical running in that wall. And since the rest of the garage was finished before I moved in, I've added outlets on the other walls with EMT. So if I decide to add outlets to the wall in question, I could just continue the run of EMT in the future.

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[Metric Mouse]

Well then! Plywood it is!

[paddedhat]

Bit late, but there is no need to fir ceilings to accommodate 1/2" rock on 24" centers. 1/2" ceiling board is widely available, and it is designed to do 24" centers without sagging. There is also a lite version of the same product that will not sag on 2' centers and weighs about a third less than standard. When it comes to adding plywood over existing rock, there are cheap plastic box spacers available to keep the outlet boxes fire rated and legal. You just need to switch to longer screws to secure the outlet to the box.