Author Topic: bedroom common wall sound, please help  (Read 25256 times)

badman70

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bedroom common wall sound, please help
« on: June 16, 2008, 02:48:29 AM »
I'm glad I found this forum, it seems there are may knowledge people willing to share advice.

I am hoping to educate myself as I am concerned about the townhome that I am having built.

I was told there would be concrete walls between the units.  I now found out that the sales guy was misinformed so I feel cheeted and now very concerned about noise. It seems there is a double studded drywall with just an air gap and double dry wall on one side (maybe both sides).  The master bedroom bed must go up against the common wall.  On the other side of that wall is 4 feet of the neighbors walk-in closet.  On the other side of the closet is most likely going to be my neighbors dresser holding a TV. 

I go to bed early because i wake up early to go to work.  I am very sensitive to noise because I lived in an apartment where I could here my neighbors stereo, TV and them snoring while I was trying to sleep.  I am not trying to completely sound proof the wall, I just want to be sure I won't hear their TV or stereo when I goto bed.  I may be jumping the gun here, since the house is still under construction.  I am just trying to get some sense of how concerned I should be and what I can start planning in advance if there is a problem. 

Based on what I wrote about the wall construction, can anyone give their best guess as to whether or not you think there will be an issue for me here?

Just to give you all available info that I have right now

The floor is all carpeted with .5" padding.  I can't think of why we would be sharing any duct work in the attic area for a townhouse.  Since behind the common wall is a 4 foot wide closet, there shouldn't be opposing outlets on either side between the same studs. 

Thank you

Dave


johnbergstromslc

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Re: bedroom common wall sound, please help
« Reply #1 on: June 16, 2008, 09:35:22 PM »
Concrete would have been best, but it still sounds like you're in good shape acoustically.  A double wall w/double drywall (assuming no insulation) will give you an STC in the mid-50's, which should be sufficient to block most ordinary noise.  And having the buffer of a walk-in closet is great, too.. 

If it's still possible, ask your builder to add insulation in the wall (R-13 batts for each side), if he isn't already.  That would raise the STC to 60 or so, a much better value.  You would probably have to spring for the cost of this yourself - most builders won't .

After the drywall is installed, make sure you're builder is doing good sealing under the wall plates and around electrical boxes.  Those would be the 'leaky' spots.  Also, you can use foam outlet and switch sealers - they work pretty well. 

If, after all of this, you're still getting a lot of flanking noise through the floor and ceiling, give a white-noise machine a try.  It's amazing how much unwanted noise they block out.

badman70

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Re: bedroom common wall sound, please help
« Reply #2 on: June 16, 2008, 11:25:51 PM »
Thank you for replying Jjohnbergstromslc,

I went to the house under construction today as I was concerned about flanking noise and I took this image.



This is a shot looking right up from the middle of the double studded wall.  I can see a piece of plywood that runs over both rows of studs.  To the right of that looks like my neighbors stairs leading from the 2nd floor to the third.  This is exactly what I didn't want to see.  I have not gotten in touch with the folks at Lennar (the builder) yet, but I read on the internet that a gap at the sub floor between the double studded wall is a fire hazard. 

Now I am really concerned.  I am paying way too much money for a luxury townhome to deal with this. 

Above the ceiling in the picture is our common family room, dinning room and open kitchen.  I can't believe it will be possible to rip out all the carpet and kitchen ceramic tile to soundproof the floor.  Any advice, it seems like I'm in trouble here.


Mark Daveis

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Re: bedroom common wall sound, please help
« Reply #3 on: June 17, 2008, 07:10:52 PM »
You have more problems than flanking noise. I mean if the air gap is connected between the 2 rows of studs by anything like metal or wood then you will get much reduced low frequency performance as the sound can just conduct across these bridge materials.Even so a loud TV with lots of bass sound will get through to some extent so I would advise getting a detached place built with brick or concrete for best noise reduction. :)

midnight

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Re: bedroom common wall sound, please help
« Reply #4 on: June 17, 2008, 07:58:01 PM »
Hi....We bought a luxury townhome last August.  We cannot hear any tv, voices, or sound, etc.  However, we can hear constant stomping of our neighbors.  This was supposed to be our first dream home.  (We live in the NYC area, and nice single family homes start in the 1,000,000, so we didn't have many options).  I think that the sound is being transmitted through the wooden structure itself.  We are in the process of adding a second wall with insulation and the isotrax system.  Did you buy the place yet?  See if you can work with the builder to install hardcore soundproofing material.  Honestly, I will NEVER, EVER buy another condo or townhome again. 

badman70

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Re: bedroom common wall sound, please help
« Reply #5 on: June 17, 2008, 10:43:58 PM »
You have more problems than flanking noise. I mean if the air gap is connected between the 2 rows of studs by anything like metal or wood then you will get much reduced low frequency performance as the sound can just conduct across these bridge materials.Even so a loud TV with lots of bass sound will get through to some extent so I would advise getting a detached place built with brick or concrete for best noise reduction. :)

The double row of studs are not (should not) be connected by anything or it would defeat the purpose of the double studded wall.  The wall is said to have an STC rating of around 55.  The part that concerns me is the connections at the subfloor and ceiling.  Hence why I was calling it flanking noise.

badman70

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Re: bedroom common wall sound, please help
« Reply #6 on: June 17, 2008, 10:49:17 PM »
Hi....We bought a luxury townhome last August.  We cannot hear any tv, voices, or sound, etc.  However, we can hear constant stomping of our neighbors.  This was supposed to be our first dream home.  (We live in the NYC area, and nice single family homes start in the 1,000,000, so we didn't have many options).  I think that the sound is being transmitted through the wooden structure itself.  We are in the process of adding a second wall with insulation and the isotrax system.  Did you buy the place yet?  See if you can work with the builder to install hardcore soundproofing material.  Honestly, I will NEVER, EVER buy another condo or townhome again. 

I have the same problem as nice single family homes are way out of my price range.  So I bought a luxury townhome.  I don't close for a few months, but it is being built now. 

You say you can't hear any TV or voices, but here stomping?  Do you have people living above you in a townhome?  This is impact noise, and I can't figure out why you would hear it if your neighbors are along the side of you.  Do they have hardwood floors. 

It's the potential for TV and music coming through that worry me the most.

midnight

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Re: bedroom common wall sound, please help
« Reply #7 on: June 18, 2008, 02:50:10 PM »
Hi.  Yup...it's weird.  They live alongside us.  They do have hardwood floors, so we must be sharing a beam or something.  We've had 3 contractors in here, and each of them didn't understand why we would have this problem.  My husband went to talk with the neighbor who was a total b**ch and slammed the door in his face.  We are in the process of getting the plans to our place and are ordering the soundproofing supplies.  We are struggling to get a contractor to actually take the job.  Good luck

badman70

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Re: bedroom common wall sound, please help
« Reply #8 on: June 18, 2008, 10:29:35 PM »
That’s interesting; from what I have learned so far, the most logical reason would be your floors are continuous. This is exactly what I was concerned about when I wrote a couple of posts ago.  I have read that it is a fire hazard to put a gap between the floors of you and your neighbor between the double studded walls.  Therefore there is no break between your floor and theirs.  And the impact of them hitting the hardwood has no way to be stopped from vibrating into your townhouse. 

 

How old is your townhouse?  Have you been able to get wall and ceiling construction information from the builder?  A contractor won’t have any idea unless he can see through all the drywall to see how the walls and ceiling/floors are constructed.  Do you have any idea what your wall construction is like (double studded, insulation)? 

 

Your continuous floor doesn’t seem to be affecting the airborne noise coming between your townhomes.  Does anyone have an explanation for that?

 

I’ll bet a contractor is going to recommend you building a floating floor above the one you use now.  Please post your progress on this, I’m sure many people are having the same problems.


Mark Daveis

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Re: bedroom common wall sound, please help
« Reply #9 on: June 18, 2008, 10:57:53 PM »
If your floor and roof dont have 55 stc as the wall then the sound will get through there to some extent.
55 stc but how much do you have at the LF sound level?
I have tested designs with 50 or so stc and with the sound turned up on a stereo at say 90 db or so then it is fairly loud inside and definately not low enough to sleep through. So really depends how loud they turn their TV up when watching movies and so on.
Impact noice is VERY difficult to reduce in a connected set of rooms because remember sound travels by conduction so you really need disconnections here to stop the impact noise or shock absorbers like springs or rubber but it really needs to be built in to the house design. :)

johnbergstromslc

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Re: bedroom common wall sound, please help
« Reply #10 on: June 20, 2008, 11:24:02 PM »
Dave:

I think you might be freaking out over nothing.  If, as you said, it is a high-end luxury townhouse, your neighbors aren't likely to be a death-metal band or a group of nocturnal frat boys.  They'll probably desire and respect peace and quiet as much as you do....

It sounds like your drawing on your experience from your old apartment, which apparently had paper thin walls and floors.  Don't worry, they build 'em quieter now - they have to.

Unfortunately, there can't be a gap in the floor at the top of a wall cavity like that.  Even if the wall is filled with fiberglass, it would still potentially create a 'chimney effect' and accelerate the spread of fire from one floor to another.  It is permissible to cut a gap and fill it with firestop caulking, but that would still create a fairly rigid connection between panels.  Also, it's counterintuitive to the builder to 'cut the building in half' like that...

Since you're still in the rough-in phase, you might want to talk to your builder and see if he'll install insulation and hang the ceiling in your bedroom with resilient channels, or better yet, isolation clips + hat channels.  You'd have to pick up the extra cost, I'm sure.  Be sure he uses double 5/8" drywall and does some good sealing, too.  Try not to use recessed lights, either.  The gaping holes you have to cut in the drywall nullify the entire effort of hanging a ceiling resiliently...

As for the floor, well, that is a tougher one...  You could install your own floating floor, but that would raise the level by 1", minimum.  Unless you could find a 'gradually sloped' threshold to transition to the regular floor level, it would present a tripping hazard.  You could probably get good results with Green Glue and a 1/2" thick piece of plywood or OSB.  The difference in floor levels wouldn't seem radically different.  Wouldn't be as good as a floating floor, but better than doing nothing.   

If you still hear unacceptable noise after the walls are buttoned up you might want to go the Green Glue route on the walls and ceiling, too.  You could put up another layer of drywall on the walls and ceiling with Green Glue.  With the added mass plus the effects of GG, you will see a definite improvement over the builders 'minimum' soundproofing.  Advantage of this method is that you're in control and not relying on a profit-motivated builder to do a quality job.  Just remember to seal, seal, seal....

Seriously, I wouldn't stress too much right now.  All is not lost once the drywall goes up.  Do what you can now, especially getting some insulation in the walls and ceilings and hanging the ceiling resiliently. 

Also, give serious thought to a white-noise machine.  I have a well-soundproofed bedroom but I still use one.  In a very quiet room (<10 dB), even a transient 30 or 40 dB noise can be disturbing and wake you up.  With a white-noise machine, you can raise the ambient noise level to 30-50 dB, still fairly quiet, but enough to drown out any stray noise leaking in, and your brain acclimates to the sound quickly - it's like a fan or space heater running.  It won't compete with your alarm clock, either.

By the way, in answer to a question in your last post, airborne noise has far less energy than structureborne noise and is damped much more quickly traveling through solid materials, like subfloor panels.  An impact of a footstep creates a large amplitude vibration in the wood itself and it is carried with less attenuation.

badman70

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Re: bedroom common wall sound, please help
« Reply #11 on: June 21, 2008, 01:45:11 AM »
Dave:

I think you might be freaking out over nothing.  If, as you said, it is a high-end luxury townhouse, your neighbors aren't likely to be a death-metal band or a group of nocturnal frat boys.  They'll probably desire and respect peace and quiet as much as you do....

It sounds like your drawing on your experience from your old apartment, which apparently had paper thin walls and floors.  Don't worry, they build 'em quieter now - they have to.

Unfortunately, there can't be a gap in the floor at the top of a wall cavity like that.  Even if the wall is filled with fiberglass, it would still potentially create a 'chimney effect' and accelerate the spread of fire from one floor to another.  It is permissible to cut a gap and fill it with firestop caulking, but that would still create a fairly rigid connection between panels.  Also, it's counterintuitive to the builder to 'cut the building in half' like that...

Since you're still in the rough-in phase, you might want to talk to your builder and see if he'll install insulation and hang the ceiling in your bedroom with resilient channels, or better yet, isolation clips + hat channels.  You'd have to pick up the extra cost, I'm sure.  Be sure he uses double 5/8" drywall and does some good sealing, too.  Try not to use recessed lights, either.  The gaping holes you have to cut in the drywall nullify the entire effort of hanging a ceiling resiliently...

As for the floor, well, that is a tougher one...  You could install your own floating floor, but that would raise the level by 1", minimum.  Unless you could find a 'gradually sloped' threshold to transition to the regular floor level, it would present a tripping hazard.  You could probably get good results with Green Glue and a 1/2" thick piece of plywood or OSB.  The difference in floor levels wouldn't seem radically different.  Wouldn't be as good as a floating floor, but better than doing nothing.   

If you still hear unacceptable noise after the walls are buttoned up you might want to go the Green Glue route on the walls and ceiling, too.  You could put up another layer of drywall on the walls and ceiling with Green Glue.  With the added mass plus the effects of GG, you will see a definite improvement over the builders 'minimum' soundproofing.  Advantage of this method is that you're in control and not relying on a profit-motivated builder to do a quality job.  Just remember to seal, seal, seal....

Seriously, I wouldn't stress too much right now.  All is not lost once the drywall goes up.  Do what you can now, especially getting some insulation in the walls and ceilings and hanging the ceiling resiliently. 

Also, give serious thought to a white-noise machine.  I have a well-soundproofed bedroom but I still use one.  In a very quiet room (<10 dB), even a transient 30 or 40 dB noise can be disturbing and wake you up.  With a white-noise machine, you can raise the ambient noise level to 30-50 dB, still fairly quiet, but enough to drown out any stray noise leaking in, and your brain acclimates to the sound quickly - it's like a fan or space heater running.  It won't compete with your alarm clock, either.

By the way, in answer to a question in your last post, airborne noise has far less energy than structureborne noise and is damped much more quickly traveling through solid materials, like subfloor panels.  An impact of a footstep creates a large amplitude vibration in the wood itself and it is carried with less attenuation.

johnbergstromslc,

You are probably right that I am freaking out of nothing, yet.  I am drawing from past experience, only this time I will own the place and can't just move.

Thank you for your insights as they have been very helpful.  I actually have more information from the builder that makes me feel a little better and want to get your opinion on it.  The common wall is claimed to have a STC rating of 55-59.  That is with double 5/8" type X gypsum, double rows of studs, R13 insulation, and a 3" air gap in between. Now, that rating seems a little low compared to what I have read on line, but the building plans claim 55-59.

My main question is regarding the information I got on the floor/ceiling construction.  It is not a continuous ceiling/floor after all.  The plywood for my neighbor runs to the first stud in the double stud wall, then a small gap and a 2nd piece of plywood covering the gap to the second stud wall.  Then another small gap then the plywood for my townhouse floor begins.  So basically they got a small independent piece of plywood covering the gap between the two rows of studs.  So it looks like the flanking path would have to propagate across the first plywood, into the stud base, into the next small plywood piece (~4"), into the next stud base, then into my plywood floor.  I couldn't fine any information on this type of construction on the net.  Do you have any insight as to how much attenuation I could expect? Or just a best guess on how much better this would be?
It probably is not a new construction novelty, yet I can't find any info on this technique.

Thanks,

Dave

johnbergstromslc

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Re: bedroom common wall sound, please help
« Reply #12 on: June 21, 2008, 10:14:17 PM »
A wall configuration like that one probably rates STC 65-67, in the laboratory.  But in the field, it's usually less, due to flanking noise.  55-59 is a realistic assessment - your builder should be praised for his honesty.  He could have gone with a higher, more theoretical number to sell you on the place but didn't.

Since your subfloor is discontinuous like that (especially if the small piece is not fastened with nails, but 'floating') I doubt you'll have any serious noise issues.

I think your builder definitely knows what he's doing.  His workmanship has impressed me, and I'm in the business...

If I were you, I'd keep checking in with the project and make sure the quality control stays high.  The next thing you might want to look for is the insulation job.  Make sure they cover the whole wall, with no holes or gaps.   Also, make sure they seal the gap under the bottom plate (before drywall) and seal any openings for electrical boxes (after drywall).     


joel

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Re: bedroom common wall sound, please help
« Reply #13 on: July 09, 2008, 06:23:42 PM »
Wow!  What a lot of interesting, complex construction discussions to answer a simple question.  Here is a simple solution that has worked hundreds of times over the last four years:
"Remodeling a  typical wall for average sound reduction: Apply Mass Loaded Vinyl (MLV) directly to the existing wall.  (Two layers is best). Stapling will hold it temporarily in place. Now install at least one layer of 5/8" firecode drywall over it.  Tape off and paint your sound deadening wall.  This will more than double the sound reduction of the existing wall."  Be sure to use two layers of MLV - that's what contractors do who do not want to get called back to fix it again louie.

johnbergstromslc

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Re: bedroom common wall sound, please help
« Reply #14 on: July 10, 2008, 12:54:59 AM »
Wow!  What a lot of interesting, complex construction discussions to answer a simple question.  Here is a simple solution that has worked hundreds of times over the last four years:
"Remodeling a  typical wall for average sound reduction: Apply Mass Loaded Vinyl (MLV) directly to the existing wall.  (Two layers is best). Stapling will hold it temporarily in place. Now install at least one layer of 5/8" firecode drywall over it.  Tape off and paint your sound deadening wall.  This will more than double the sound reduction of the existing wall."  Be sure to use two layers of MLV - that's what contractors do who do not want to get called back to fix it again louie.

MLV sandwiched in between 2 layers of drywall doesn't do shit.  It's the added mass of the extra drywall improving the sound reduction.  Skip the expensive MLV, add 2 additional layers of drywall.   

 

anything