Author Topic: What to do to help seal after drywall?  (Read 5599 times)

badman70

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What to do to help seal after drywall?
« on: August 26, 2008, 12:40:07 AM »

The drywall is going up in about a week in my townhome.  I have been trying to do anything I can to help ensure the most soundproof wall possible.

I have redone the putty in back of the electrical boxes (the contractors did a sloppy job)  I am putting up extra insulation at least in the bedroom.  I noticed that the builder uses open faced batts which are not stapled in place, so I think the insulation is going to fall into the cavity by the forced air as they put the drywall into place.  I guess there is nothing I can do about that.  Should I use paper faced and staple to the inside of the studs?

From the looks at the other townhouses ahead of mine in construction, it doesn't look like they caulk under the drywall.  Once the drywall goes up, what should I do at this point.  I can caulk the corner of the drywall and floor before they bring in the carpet.  I don't know what to do about the sides and ceiling though.  I know I can caulk around the electrical boxes after I close, so I not in a hurry for that.

Any suggestions. 

johnbergstromslc

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Re: What to do to help seal after drywall?
« Reply #1 on: August 27, 2008, 12:44:15 AM »
Well, the unfaced insulation won't fall into the cavity from the force of the drywall going up, but it might sag a bit over the years, or decades really.  It's probably not enough to worry about, but you are right, paper-faced insulation stays in place better.  If you are installing extra insulation, make sure you cut it at least an inch longer than the actual stud cavity and 1/2 inch wider; rolls of standard batt insulation are 15" wide for a 14.5" cavity.  You'll have to bend it a bit to install, but when you fluff it up you'll get a nice snug fit, with no gaps around the edges.

Now would be a perfect time to seal the gap between the bottom wall plates and subfloor.  If possible, seal the same gap in your neighbor's wall, too, or any other gaps that might compromise your soundproofing.  If you're really gung ho about it, you could seal the gaps between your subfloor panels, too.  The subfloor should be tongue-and-groove OSB/plywood and sometimes builders will put a bead of construction adhesive in the groove before nailing it down, but if not the grooves perpendicular to the joists can sometimes be the source of a sound leak.

As for sealing in general, you should 'think like water'.  Imagine the room you're building is an aquarium (ignoring the fact that drywall is porous, of course) and seal up every little gap, crack or penetration that water could leak out.  It's actually much easier for sound to leak through a small hole or gap since, unlike water, air has negligible viscosity, no surface tension and sound travels at ~1000 ft/sec, so be obsessive/compulsive about sealing and don't skimp on the caulking.  Be sure to use the good, flexible stuff too.  The caulk sold on Super Soundproofing is a pretty good deal - 10 bucks for a 29 oz. tube.  Otherwise, be prepared to spend at least 4 bucks for a 10 oz. tube at the home center.  That's what a quality silicone caulk costs.       

badman70

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Re: What to do to help seal after drywall?
« Reply #2 on: August 27, 2008, 11:30:41 PM »
Thanks,

Because of my time window, I can't wait for delivery by ordering acoustical caulk.  I been searching all day for a place that sells acoustical caulk and have yet to find someone who has ever heard of it.  Since I'll be out of time in about 5 days, what alternatives can I use at home depot or lowes.  Or do you know of any store that sells something I can use?

Mark Daveis

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Re: What to do to help seal after drywall?
« Reply #3 on: August 28, 2008, 09:37:10 PM »
Just use a good quality silicone from any DIY store. :)

badman70

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Re: What to do to help seal after drywall?
« Reply #4 on: August 28, 2008, 11:26:08 PM »
I'm good now. I went to a drywall supplier and got a case of 29oz OSI-175 for 3 bucks a tube. 

I thought that was ridiculously cheep.


johnbergstromslc

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Re: What to do to help seal after drywall?
« Reply #5 on: August 29, 2008, 10:01:36 PM »
I'm good now. I went to a drywall supplier and got a case of 29oz OSI-175 for 3 bucks a tube. 

I thought that was ridiculously cheep.



Yeah, sounds like you got a good deal.

bjnash

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Re: What to do to help seal after drywall?
« Reply #6 on: September 01, 2008, 03:39:38 PM »
I'm good now. I went to a drywall supplier and got a case of 29oz OSI-175 for 3 bucks a tube. 

I thought that was ridiculously cheep.


These materials have a shelf life.  The closer it gets to the "End of Life" the cheaper it can get.  He was probably glad you came to take it off his hands.

BJ Nash

 

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