Can drywall be adhered to other drywall?

Question

I have a lot of work to be done in my home involving drywall because large windows were sized down... recently a leak in the kitchen with mold growing caused a ceiling issue too... I bleached away the mold but the paint peeled back because someone had used two different paints (oil/water)...I think that spot needs to be cut out/replaced then I was going to peel all the other paint off of the ceiling... no more leaking--someone re-caulked things with roofing tar... but someone suggests just slapping new drywall on top of the existing ceiling drywall creating a whole new kitchen ceiling when re-walling the rest of the kitchen.... how will i ever know if there is a leak there again... this leak was apparently there for awhile before it was noticed because the paint cracked a bit, then i peeled it back and found the mold and wetness...there was no dripping... someone else said that doing this method can cause sweating between the two walls, like if done on walls instead of tear down...--??

all of the roof vents were recaulked with roofing tar and it has rained a lot since then with no more leaks so apparently that was the problem...

i was told that since the leak has stopped any moisture on the other side of the drywall (that inside the crawlspace) would have dryed up and so therefore mold would not be growing on the drywall on the other side anymore if it ever was...they didnt this time go into the crawl to find the leak, they only caulked the vents which solved the problem....

Answer 1

Poor you, what a mess, I would start over for safety and less work in the future, just do it right.

Answer 2

I wouldn't put a layer of drywall over another one, for several reasons.

If the problem isn't fixed, the leak will still come through the new layer.

Any mold or mildew is still there, and will spread.

You'll have a lot of weight hanging above you when you're in that room. The screws holding the new stuff up may someday be holding the old stuff, too - it might come down.

The ceiling height won't be the same as the other parts of the house.


I would cut out the bad spots, and put in new drywall there. If the whole ceiling has to come down, then that's what you do. It'll be messy, but at the end you'll feel comfortable with it, knowing it's done right.

Answer 3

I'm a drywall contractor. Bottom line: drywall will mold if it stays wet and can't dry out quickly. That being said you need to make SURE the leak has stopped. Secondly, make sure ALL of the mold is gone and that everything is completely dry...framing, insulation, drywall. If your insulation got wet, it needs to be replaced.

If everything is dry and you are sure the leak is fixed, then yes you can just add a second layer of drywall over the existing ceiling. This is known as laminating. You need to use 2 inch drywall screws when installing it though, and make sure you screw into the ceiling joists, not just the other layer of drwall.

I would only laminate if you are completely sure everything is dry and mold free. If you had a lot of water up there you need to tear down the drywall to inspect the framing and insulation for mold and rot. It's not a fun job but you don't want to mess with mold.

Answer 4

To answer your first question, yes. You can use 1/4" drywall and "Liquid Nails"---just put spots of liquid nails on the ceiling and press the new drywall right on it, holding it in place for a few minutes. Then you would tape and finish as usual. There are other ways to address the existing (marred) finish also. An oil-based sealer such as Kilz will dry fast and allow you to go over the whole thing with another layer of latex paint. Actually, that would be much easier and is probably the way I'd go.

Answer 5

Yes the ceiling can be laminated with another layer of drywall this is not a problem and is safe. You have been given a lot of conflicting information. The leak is not fixed if they smeared tar on something. That's a temporary patch. Fix the ceiling and find somebody that can fix the roof. You are right, you cannot put latex paint over oil paint (they won't bond). Good Luck.

Answer 6

Tear it down, fix the problem causing the mold, and start over. The old dry wall and mold, even if you think you got it all, will make a mess of new drywall.. Plus more drywall will start encroaching on your space! It does sound like someone used the wrong paints together. Latex and oil will cause the paint to peel.. It should cost you less to start over than to keep fixing!

Answer 7

It would be best to remove the drywall and replace. Adding another layer could cause a weight issue and bring down the whole ceiling.

If you are still unsure about what you want to do once everyone else has answered please contact a professional for advice.

Good luck

Answer 8

ur best bet is to remove the drywall, check the insulation for dampness, u can call a home inspector to use a moisture meter for a final check.......

if u take the short cut, most of the time it will come back to bite u in the butt!

lic. gen. contractor

Answer 9

I think you could screw new drywall over the old , you would have to use longer nails of course, and box extensions for the electrical.

Answer 10

you have to tear down the old dry wall or youll have alot of problems later,with sweat and mildew