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What to fill gaps in drywall with? Channel Strip Plugins
Old 30th March 2010
  #1
Gear Maniac
 

What to fill gaps in drywall with?

Hey everyone,

I just finished with drywall on the ceiling. I have same gaps I need to fill in around the cut-outs for pieces of metal holding the garage door rails. What should be used to fill those gaps up? (bondo, water putty, mud, caulking?)

Also, after I fill in the holes/gaps and finish with tape and mud, I thought of a way to check for leaks. I was thinking of standing in the new attic with all the lights out except for someone underneath me, under the new ceiling with a bright light. Now I figure I would see light leaking through anywhere that needed to be sealed. Would this work?

Thanks
Old 30th March 2010
  #2
Gear Head
 

From the information you provided are we to assume it is a single layer of drywall you installed? (otherwise the staggered seams of successive layers of drywall would insure no leaks)

if so what is the thickness of the drywall? If < 5/8" I would just stuff the larger gaps with pink stuff, try and clean up the visible edges, and seal over it with some caulk. If it is 5/8" or thicker I would try and patch over it with smaller, well cut pieces, then mud and tape it normally.

while you are doing drywall though, and you are at all concerned with isolation, you might be better off to just go ahead and do a second layer, +GG if the budget allows.

-B
Old 30th March 2010
  #3
Gear Maniac
 

Just finished second layer...

I actually just finished the second layer(5/8)+GG in my one car garage. The metal pieces that hold up the garage door rails and the opener are attached from the studs on the ceiling and I have made small cut-outs in the drywall to fit it in (before there were foam tiles). So these gaps are present in both the first and second layer. I was wondering if it wouldn't be better to fill that in solid with plaster or something similar.

What is pink stuff?
Old 30th March 2010
  #4
Gear Maniac
 

While regular drywall mud may work, I wouldn't expect it to last long. You will need something resilient to handle the movement (vibration, thermal contraction) of the metal rails.

As we can't see the situation, only guesswork is possible. I see a couple options though. You want something that will maintain a seal while experiencing some minor movement. Sound sealant caulk and backer rod or other foam may work. I might resort to canned foam ('Great Stuff', etc.) for this purpose. It is sticky, will adhere to both sides, expand to fill the gap completely, and it will remain flexible enough.

Another issue which you may not have thought about is the problem of the rail itself, because it is penetrating the wall. You now have a nasty flanking path of vibrations transmitting right through the metal. You will probably want some serious mass and damping on that rail. You may even need thermal insulation if you live in an extreme climate.

Nathan
Old 31st March 2010
  #5
Lives for gear
 
Disjointed's Avatar
 

+1 on the expanding foam in a can, i regularly use this to seal 'unfortunate' gaps in drywall. Trim it flush after it has cured, Then tape and caulk over it as usual.
Also, if you are finishing your own drywall, for long term drywall stability, i recommend you use 'setting type' drywall compound(in a bag), it dries much harder then premixed = a great first coat. Then second and third coats, use premixed, for a smoother finish.

gl
Old 1st April 2010
  #6
Lives for gear
 
Bob Ross's Avatar
 

Quote:
Originally Posted by Tennis View Post
So these gaps are present in both the first and second layer.
Old 2nd April 2010
  #7
Lives for gear
 
jhbrandt's Avatar
Quote:
Originally Posted by Tennis View Post
I actually just finished the second layer(5/8)+GG in my one car garage. The metal pieces that hold up the garage door rails and the opener are attached from the studs on the ceiling and I have made small cut-outs in the drywall to fit it in (before there were foam tiles). So these gaps are present in both the first and second layer. I was wondering if it wouldn't be better to fill that in solid with plaster or something similar.

What is pink stuff?
Yes, I think 'ruh roh' is in order.

Did you follow instructions on the green glue?? Did you overlap seams?

Filling with expanding foam will bridge the pieces of drywall. I would suggest putting the expanding foam in the hole on top of the drywall then backer rod & caulk. IOW, use the expanding foam for a backer for the caulk. heh You should use an acoustic rated caulk such as OSI SC-175 for sealing the joints in each layer of drywall. Joints around the walls and metal pieces should be sealed with this same caulk. It remains pliable for years. This will also allow the Green Glue to have it's maximum effect.

If you have any air/sound leaks - You have completely wasted all your money on the green glue. Sorry. - Just a fact.

Insulation in the ceiling is very necessary too, not just for thermal considerations.

Pink stuff is referring to Owens/Corning pink fiberglass.

Nathan, I don't think he's going to have any noticeable (flanking) trouble from the metal except for leaks.

Keep us posted.

Cheers,
John
Old 3rd April 2010
  #8
Gear Nut
 

Tennis, get a tube of osi-175, squirt a bunch into a ziploc,(or a whole tube if you have more of the bigger gaps, put it in the fridge. While it is chilling,(not freezing) put backer rod in, get 5/8 from Home Depot. When your caulk has firmed up you can spread it in your holes and it won't sag. It won't hurt the caulk a bit to chill it, it will fill a big gap. Now the bad part. It can't be your 1st time using a drywall knife. It won't sand out. You have to make sure any lap marks and such are below finish level. In other words you can make a mess out of it.(we have all seen the bad caulk job on a tub in a motel) It even says on the tube "tooling not recommended." not that you can't, but... I had several cases get cold and either they were hard as heck to push out or the tube would fail. So I cut one open to see if I could still use it. The chilling affected spreadability but not it's adhesion or flexibility after drying. Likewise if you want to hall ass caulking set it in the sun first. Tips on spreading. use 2 knifes,6 and 10", not a pan a knife, load the same length on your knife as your hole (you don't want to spread the caulk where you don't want it) and pack it in a perpendicular stroke, now clean your knife real good and take 1 pass to clean excess and level. don't touch it. 1 or 2 strokes! more than that is recipe for disaster.
Old 4th April 2010
  #9
Lives for gear
 
jhbrandt's Avatar
+1

"1 or 2 strokes! more than that is recipe for disaster." <-- He knows what he's talking about.

Last edited by jhbrandt; 4th April 2010 at 03:33 AM.. Reason: hit submit to quickly
Old 4th April 2010
  #10
Lives for gear
Quote:
Originally Posted by Tennis View Post
Hey everyone,

I just finished with drywall on the ceiling. I have same gaps I need to fill in around the cut-outs for pieces of metal holding the garage door rails. What should be used to fill those gaps up? (bondo, water putty, mud, caulking?)

Also, after I fill in the holes/gaps and finish with tape and mud, I thought of a way to check for leaks. I was thinking of standing in the new attic with all the lights out except for someone underneath me, under the new ceiling with a bright light. Now I figure I would see light leaking through anywhere that needed to be sealed. Would this work?

Thanks
The mud will probably crack from movement...
Do you have any plans of adding some cieling diffusion?
Could you use wood strips or blocks as part of your diffusion array to gain some cieling diffusion, and block the gaps in tight enough to the garage rails for silcon flexable calking?
Old 5th April 2010
  #11
Gear Maniac
 

so...

What I ended up doing is making little cutouts of the holes out of some drywall scraps I had and then I used caulk to fill in the edges. I then went up to the attic and shot in some Great Stuff to fill in any left over holes. I'm happy with the results. I realize now that it would have been easier to hold on to the cut out pieces and use those to put back into the holes, oh well.

My next project is to seal the door tight.
Old 8th April 2010
  #12
Gear Maniac
 

done with the door...

So I added some trim and sealed the door tight. The door has to be shut rather hard in order to shut completely. Is that going to be ok?
Old 8th April 2010
  #13
Gear Maniac
 

I want to add that the door seal is perfect when I get it shut.
Old 8th April 2010
  #14
Lives for gear
 
jhbrandt's Avatar
Very good.
Now have someone outside check levels while another is playing drums inside to see if the door has enough transmission loss. If not, you will need to add more mass to the door.

Good luck,
-- John
Old 9th April 2010
  #15
Gear Maniac
 

It is a solid core door. Would fastening drywall to the door be a good way to add mass to it? Also, I have some GG left over, would it be worth it to use that between the door and maybe a couple layers of drywall.
Old 11th April 2010
  #16
Gear Nut
 

drywall not the best choice. mdf is what to use. and definitely use your GG.John Sayers' Recording Studio Design Forum &bull; View topic - What kind of doors are you guys using?
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