Drywalling a garage – drywall to concrete area
I have been hanging and taping drywall for about 10 years now. I have done full rooms and repair work and even a couple of basement jobs but I have never done a garage. My question is on materials and what to put between the concrete and the drywall. I use greenboard in the bathrooms and kitchen areas because of the excessive moisture. Should I also use green board in the garage because it is not tempature controled and there is the good chance of the customer hosing down the inside of the garage. I will paint the dywall but is that enough? And what about the area between the concrete and the drywall. What is the distance between the board and the concrete to be and how should I finish it. I can not find anything on the internet on proper construction techniques for these questions. Can anyone help me?
Replies
man
Tough question.
If they're hosing it down, I'd give serious thought to at least going a step above MR board. There's exterior graded drywall the might stand a fighting chance.
or
Durock as a 1' starter and skim it....................
At least hold it up as much as you can. In most cases here a stem wall/block foundation will take it 6" or more, that's a start.
Still, MR or reg board can't sit in water. All the sealer in the world won't help it. Rubber base at the bottom won't keep it from getting up and behind.
What does USG say-I'd call them. If you do, come back with their recommendation.
Actually, the ideal is probably fiberglass-reenforced board. I don't know what you call it officially, but I've seen it used for firewall in some commercial applications -- kind of halfway to cement board, and very rugged. Should resist both moisture and mechanical damage.
And in a garage one needs to check codes to see if any sort of fire-resistant treatment is needed, especially on a shared wall.
Any board should be held at least 1/2" from the floor, to prevent moisture on the floor from soaking up.
I know someone here will think I'm nuts, but I put up 12" of durorock around my garage. Leave the smooth side out and flll the gaps with caulk. I put a pvc base-trim on it as well. It still needs to be painted but it's held up for two cold winters so far with no problems.
DW
Is the garage attached or detached? If attached the common wall with the house needs to be 1 hour fire rated, which means f/c drywall that you can get in 1/2 or 5/8".
Calvin's Duarock strip would be my choice for the bottom and hold it 1/2" above any concrete wheather it is a stem wall or the floor. You could skim coat it as mentioned , but covering it with FRP (fiber reinforced plastic as DanH suggested from 2 to 4' in height will make that part pretty much bomb proof.
I used that technique in a kennel building and it has held up great for the past 4 years. I also used 1/2" backer rod in the gap below the drywall. I did not caulk the backer rod in place because I only wanted to use it as a cappilary break. between the floor and the bottom of the cement board. Covered the whole shebang with FRP paneling and caulked the panel to floor joint with a good polyuretane, then applied a pvc baseboard. So far neither the dogs or washing the area with a hose has damaged anything.
I'm not sure about any fire rating for FRP. It may be as much as 1/2 hr., in addition to the duarock and/or dry wall fire rating, You'll need to check your local codes to see what you need if it is a party wall with the house.
Might be a little higher cost job than the HO was asking for, but I can almost garruentee that method as a bullet proof job, that they will not have any problems with for years to come. And, you won't have any call backs for moldy drywall replacement.
Actually, I wasn't suggesting FRP but rather fiberglass-reenforced gypsum board. But the FRP is a good idea too.
FYI ... the exterior drywall is purple in color, I think. I became a bit familiar w/ it just recently when a contractor was drywalling before a building was roof ready.
clew
The ext. board I mentioned was darker grey for the gypsum, the paper was a dull black (or damn dark grey) , no beveled edge. The paper could have possibly been "impregnated" to bring ouit that dark color-don't know.
It passed the commercial storefront "fire rating" at the time.................must have been at least an hour-it was 5/8's board.
Yeah, I've seen stuff like that used as a stucco backer.
If you've been doing this for ten years, you haven't been paying attention. Let me explain ....
Proper drywall installation never has the drywall touch the floor; there's always a gap. This isn't a problem, because the floor plate closes off the bottom of the cavity- and the baseboard hides that 3/4" or so at the bottom of the wall. The size of the gap will vary, as floors are not flat.
You're right in suspecting that moisture and drywall don't get along. There's no 'ordinary' garage where drywall won't work. If you want further protection, you can improve things. Here are some suggestions:
- Prime the walls with Kilz, or some other shellac product, before painting;
- Use a tall plastic or rubber baseboard material;
- Cover the lower part of the wall with FRP; or,
- Do the lowest part of the wall with tile backer board.
Thank you very much to everyone that responded. I will take all the options and create different quotes for the customer in different price ranges. Thank you again.