Author Topic: Reducing (not soundproofing) sound coming in from attic?  (Read 6910 times)

MCF

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Reducing (not soundproofing) sound coming in from attic?
« on: November 21, 2009, 08:22:32 PM »
I have a three story free standing townhouse style home (tall and skinny).  We have two bedrooms on the 3rd floor.  One master and one smaller bedroom.  The smaller bedroom is in the back of the home and has a large window facing a street with a lot of activity (restaurants, bars, etc. etc.) and have NO noise in it.  The master bedroom room is in the front of the home away from all the activity and sometimes we can hear noise in our master bedroom from the street a block behind our home.  Above both rooms is the attic.  The big difference between the two rooms is the master has a coffered ceiling with four can lights.  The smaller room is not coffered and no can lights.  It appears to me that sound may be coming in from the coffered ceiling of the master and the can lights in the attic.  My question is, if I put much more spray insulation or even spray expanding foam insulation in the attic, particularly above the master, would it help reduce outside noise?  Thanks!

johnbergstromslc

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Re: Reducing (not soundproofing) sound coming in from attic?
« Reply #1 on: November 23, 2009, 12:54:06 AM »
It's not just possible, but likely that the sound is leaking from the holes in your ceiling.  Expanding foam would only help a little, but I'd suggest spending a little extra money and having an electrician replace your recessed light housings with 'airtight' boxes that seal up good.  Another benefit is that you can put insulation right up against the box without burning your house down. 

If you really want good soundproofing, I'd also recommend 'boxing up' the new light housings inside the joist cavity.  Install blocking around the box, a couple inches narrower than the joist.  Insulate around and on top of the box and cap off the top with 2 layers of drywall to add mass.  Then get some good silicone caulking and seal, seal, seal - any little gap where sound might conceivably get out (or in). 

It's a lot of work, but peace and quiet will be well worth it.

MCF

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Re: Reducing (not soundproofing) sound coming in from attic?
« Reply #2 on: November 23, 2009, 04:22:47 PM »
Thanks.  The cans are already airtight I beileve.  The cans have been in the attic for 4 years and have spray insulation all around them and have never had a problem.  What would be easiest way to soundproof these from the attic without having to cut the drywall in the ceiling of the bedroom?  Could I simply build a three sided box and seal it to the top of the drywall in the attic with silicone?

What about using something like this?

http://www.soundisolationstore.com/quietbox-recessed-light-soundproofing.html

Could I build something like this so that it sits around the existing can lights and use Silenseal to attach the box to the existing drywall and then silicone the heck around the edges where the box meets the existing drywall?

johnbergstromslc

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Re: Reducing (not soundproofing) sound coming in from attic?
« Reply #3 on: November 25, 2009, 11:30:27 PM »
Could I simply build a three sided box and seal it to the top of the drywall in the attic with silicone?

Could I build something like this so that it sits around the existing can lights and use Silenseal to attach the box to the existing drywall and then silicone the heck around the edges where the box meets the existing drywall?

Yeah, that's basically what I was suggesting when I said to 'box up' the recessed can.  You need to restore the ceiling mass lost when they cut holes in the drywall to install the cans. 

You could try the Silenseal if you want, but if you're handy and have a few tools, you could do it yourself with simple materials and save quite a bit of money... 

MCF

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Re: Reducing (not soundproofing) sound coming in from attic?
« Reply #4 on: November 26, 2009, 03:36:13 AM »
Thanks.  If the top of the cans are below the tops of the beams, could I use the sides of the joists for two sides of the enclosure?

Also, as the cans are already surrounded by blown insulation and they do not get hot when the are on (I checked) would having a company come out and blow another 6" of insulation in the attic help at all?

 

anything