# Bathroom soundproofing: QuietRock or Roxul?



## 92469 (Oct 20, 2010)

Hi guys,

We gonna be adding a small powder room to our house in a few months. The only place we have for it is of the dyning room. So, I'm naturally concerned with soundproofing it. I'm thinking about either going with QuietRock instead of sheetrock or Roxul insulation.

I suspect QuietRock is gonna soundproof better just based on STC ratings I've seen but what's your take on it? What's gonna be more cost effective, going with QuietRock + the regular insulation or Roxul insulation + the regular sheetrock?

One more question please. When installing QuietRock, does it need to go on inside *and* outside of the frame, or would just using it on one side be OK in order to cut the cost? Don't wanna cut the corners there but don't waste money either.

Thanks in advance!


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## Avadon (Apr 20, 2011)

SM05 said:


> Hi guys,
> 
> We gonna be adding a small powder room to our house in a few months. The only place we have for it is of the dyning room. So, I'm naturally concerned with soundproofing it. I'm thinking about either going with QuietRock instead of sheetrock or Roxul insulation.
> 
> ...


I'm guessing you don't want someone in the bathroom and the dining guests being able to hear their tootleage. lol How big is the bathroom? If it's not to big than quiterock won't be that expensive. However I doubt you really need it. Keep in mind most bathrooms that share a dining room aren't even insulated. I would be surprised if you insulate that interior wall and use 5/8's drywall that would you even need quiet rock. But the quiet rock wouldn't hurt. Keep in mind your quiet rock isn't a immediate fix all. Sound travels through ducting, through ceiling and floor as well as outlets and the most obvious transit place, the door. Might want to put a sweeper under the door for sound and odor and make sure you have a good solid door on that bathroom. Because without that all the quiet rock won't mean a thing.


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## Avadon (Apr 20, 2011)

Much cheaper than quietrock is the standard soundboard you can get at lowes and depot. I've used this a lot and it's quiet decent stuff. It's not quiet rock, but insulation + sound board + 1/2" or 5/8's drywall is an impressive amount of sound deadening. But people are always surprised at how much sound travels under a door or through a cheap door as well as through ventilation and any other susceptible place. At like $50-60 a sheet the quiet rock adds up quick. Also keep in mind that quiet rock is only as good as the system your putting it on. A 2x4 system being the weakest, 2x6 better, 2x4 staggered stud, 2x6 staggered stud, double wall, and so on. 

I had to do some digging to find this again.. but take a look at this for STC values.

http://www.specjm.com/files/pdf/wood_framing.pdf

This will give you a really good idea of systems and their STC values. After seeing this you may reconsider spending the money on quiet rock. After all no one will be jack hammering in the bathroom *(you hope)


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## 92469 (Oct 20, 2010)

It's gonna be 32" x 60". Yeah, that's all I have to work with in our old house. The plan was to insulate it regardless. And we can only use 1 sheet/layer and may have to use 1/2" drywall, as well as 2x3 vs 2x4 simply because we don't have much room to work with there. I'm guessing that takes soundboard out of the picture.

So, taking the above into account, ie stuff I neglected to mention :whistling2:, would you go with QuietRock or (Roxul) insulation instead?

Will make sure sweeper is there and yep, solid wood door is gonna go in. Both are very good suggestions.

Thanks again!


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## Ted White (Jun 23, 2009)

Actual acoustic lab test values for sound board really aren't impressive. The issue is that you insert screws through all that sound board and severely limit it's ability to compress.

The pre-damped drywall (there are 5 manufacturers of this type of product) are typically very expensive relative to the benefit. They are typically lightweight, but we need the mass. They often have limited damping due to limited damping material to save cost. Also pretty pricey to cut and fill your dumpster with the scrap.

I would suggest you simply add the mass of standard drywall. Perhaps a double layer of 5/8" drywall. you could field damp that drywall if you like.

The insulation should be nothing more than standard (thermal) R13 fiberglass. Insulation does little as it is, so no sense spending more for insulation that won't perform better than standard insulation.

The door is the weakest link here. The door is much lower mass that the wall and there's no beneficial air cavity. Also... there's that big gap at the bottom of the door. The #1 source of sound escaping. Consider a solid core door and look at an automatic door bottom which will seal that gap when the door is closed.


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## 92469 (Oct 20, 2010)

Hi Ted,

I remember you answering my other soundproofing question. 

We probably posted our replies about the same time. There I mention that I don't think I can do 5/8" or multi layer installation due to the real estate constrains. I may just have to go with a single 1/2" layer instead, hence my thinking I may need to use something else instead of the regular sheetrock and/or insulation.

Thanks!


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## Ted White (Jun 23, 2009)

Well, MLV is quite heavy and takes up 1/8" or 1/4" of space. When real estate is tight as you say, that's a common choice. 

Or add 1/2" drywall and a field application of damping compound. Or both technques.


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## rightit (Mar 5, 2011)

A different approach:

You could use Green Glue and an additional layer of sheetrock on the _dining room_ side of the wall. Be aware that sound is like water and will find unaddresed paths such as common joists and under doors. The joists shouldn't be a real issue for the bathroom (but if you're removing the sheetrock from the ceiling, you may as well deal with it), but a good solid door with an automatic threshold or door sweep will be useful, as well as making sure that you address the dead space between the rough door frame opening and the hung door frame.

Here are some good articles on soundproofing. Again, given that this is a bathroom, extreme measures shouldn't be neccessary:

http://www.soundproofingcompany.com/library/articles/

Also, when you choose a ventilator, you could skip the quiet ones and get one that provides a 'white noise sound blanket'. 

Mark


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## 92469 (Oct 20, 2010)

Hi Mark,



rightit said:


> A different approach:
> 
> You could use Green Glue and an additional layer of sheetrock on the _dining room_ side of the wall.


Right, I'm aware of that approach but can't do that due to lack of room I'm afraid (see my earlier replies). 



rightit said:


> Here are some good articles on soundproofing. Again, given that this is a bathroom, extreme measures shouldn't be neccessary:
> 
> http://www.soundproofingcompany.com/library/articles/


I might actually have it bookmarked some place. Thanks!



rightit said:


> Also, when you choose a ventilator, you could skip the quiet ones and get one that provides a 'white noise sound blanket'.


Yeah, good point. I was thinking about getting it wired so that it's automatically on when turning the lights on in the bathroom.

Thanks again.


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## Ted White (Jun 23, 2009)

What did you wind up doing?


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## 92469 (Oct 20, 2010)

Sorry for the later reply, been busy living through the project (I work from home). Fun fun... After considering all of the replies, we're going with 1/2" QuietRock on one side and just the regular sheetrock on the other one, plus the regular R13 insulation. Thanks again.


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## Ted White (Jun 23, 2009)

Look at the lab data for that panel you're contemplating...

I would suggest you consider using a layer of standard 1/2" drywall and a field application of damping compound. This satisfies your need for a 1/2" product. You will also be significantly damping your original drywall. THat's important. Applying a layer of pre-damped drywall will not appreciably damp the original wall.

This solution is less expensive and higher performance.


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## 92469 (Oct 20, 2010)

Thanks Ted. Can damping compound be picked up at the local hardware store? If so, do you know the name of the product by any chance? Thanks so much!


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## Ted White (Jun 23, 2009)

You are looking for Green Glue. That's the damping compound. I'm in the soundproofing industry so I try and avoid open endorsements of products to keep things civil and objective online. But you asked. http://www.soundproofingcompany.com/products/green_glue_pails/


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## 92469 (Oct 20, 2010)

Thanks Tedd. I was aware of Green Glue. Was thinking that perhaps you were referring to something else.


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## Ted White (Jun 23, 2009)

My pleasure


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## mel_kissmygrits (May 22, 2010)

Avadon said:


> I would be surprised if you insulate that interior wall and use 5/8's drywall that would you even need quiet rock.


Been down this road before.. 1/2" sheetrock and R-13 insulation cuts down on some noise, not all. Double hanging 1/2 or 5/8 with a layer of green glue (acoustical caulk) will make the difference.


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## Ted White (Jun 23, 2009)

Agreed. Double 5/8" is desirable due to the added mass.


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## mel_kissmygrits (May 22, 2010)

I was surprised at how much more expensive 3/4" sheetrock is. In my area 3/4 x 12' is ~$20 a sheet vs. 5/8 x 12' @ ~$10 per sheet.


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## Ted White (Jun 23, 2009)

Odd sizes get a premium. 1/4" is as expensive as 5/8" many times for example


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## jklingel (Dec 21, 2008)

You can always go real low tech, and have a radio on pretty loud. Or, a cheap, noisy exhaust fan. At least you won't hear the bodily noises. PS: Just make sure the radio is not playing rap, or the guests may be vomiting in the living room.


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## pyper (Jul 1, 2009)

None of it's going to make any difference if you hang a standard door.


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