Portland, ME · Member since 2012 · 616 posts · 550 votes
I recently purchased a 12 unit building which I would like to take from class C+ to class B+. There are two 3 bedroom units on the second floor and the rest are 2 bedrooms. I was just given notice (for November, not great timing) that the two units below the 3 bedroom units are moving out. The noisy kids upstairs are a factor. The 3 bedroom units will probably always have kids, so this will continue to increase my turnover. I am considering sound-proofing the lower units by adding a product called QuietRock to the ceiling and shared walls. Has anybody used this or is there a less expensive product you know of? The ceilings need work anyway.
There are a variety of products out there for sound proofing ranging from practical to what you would use to build a recording studio ;-)
QuietRock and other products like it are a double layer of (typically 1/2") sheetrock with a baffle between them designed to dissipate sound waves. Are you planning to install this over the existing ceiling or to replace the drywall which is there now?
Your existing ceilings between units should be 5/8" fire rated drywall suspended from resiliant channel to meet modern fire code. If your ceilings are not already this configuration and you are planning to pull them down, then you may be able to sound proof sufficiently while fire rating your ceiling.
When fire rating common walls and ceilings, we fill the cavity with a layer (or two) of Roxul Safe-n-Sound (or an equivalent dense stone/rockwool), sometimes in combination with the denser Roxul Comfortboard {for additional firestop}. Over that we strap the wall/ceiling with resilient channel - the resilient channel both provides better hold for the sheet rock in the event of a fire {i.e. ceiling stays up longer} and, by suspending the drywall off the floor joist reduces the low frequency sounds/vibrations from the floor above {i.e. running little kids or pets}. Finally the 5/8" fire rated drywall is installed.
The 5/8" fire rated drywall itself is not as good a sound baffle as the QuietRock, or using baffle plates on the ceiling, but when combined with the rock wool and resilient channel it comes close while meeting the fire stop requirements necessary in a multi-unit building.
You could use the rock wool, resilient channel, and then hang the QuietRock (which is 1-hour Fire-X rated) to achieve greater noise reduction. {Note: PABCO Gypsum claim QuietRock can be attached directly to the studs/joists without resilient channel. I would first verify with your local building inspector or fire marshall that it still meets fire code when installed in this manner}.
I've used QuietRock in a number of units and it is nothing short of amazing in terms of sound reduction. Before I did that I also tried putting cellulose insulation in the ceilings and that really did nothing. Yes, the sheets itself are more expensive but the main cost is labor. If you need to do ceiling work anyway the added cost of the material is well worth it.
There are a variety of products out there for sound proofing ranging from practical to what you would use to build a recording studio ;-)
QuietRock and other products like it are a double layer of (typically 1/2") sheetrock with a baffle between them designed to dissipate sound waves. Are you planning to install this over the existing ceiling or to replace the drywall which is there now?
Your existing ceilings between units should be 5/8" fire rated drywall suspended from resiliant channel to meet modern fire code. If your ceilings are not already this configuration and you are planning to pull them down, then you may be able to sound proof sufficiently while fire rating your ceiling.
When fire rating common walls and ceilings, we fill the cavity with a layer (or two) of Roxul Safe-n-Sound (or an equivalent dense stone/rockwool), sometimes in combination with the denser Roxul Comfortboard {for additional firestop}. Over that we strap the wall/ceiling with resilient channel - the resilient channel both provides better hold for the sheet rock in the event of a fire {i.e. ceiling stays up longer} and, by suspending the drywall off the floor joist reduces the low frequency sounds/vibrations from the floor above {i.e. running little kids or pets}. Finally the 5/8" fire rated drywall is installed.
The 5/8" fire rated drywall itself is not as good a sound baffle as the QuietRock, or using baffle plates on the ceiling, but when combined with the rock wool and resilient channel it comes close while meeting the fire stop requirements necessary in a multi-unit building.
You could use the rock wool, resilient channel, and then hang the QuietRock (which is 1-hour Fire-X rated) to achieve greater noise reduction. {Note: PABCO Gypsum claim QuietRock can be attached directly to the studs/joists without resilient channel. I would first verify with your local building inspector or fire marshall that it still meets fire code when installed in this manner}.
Thank you for the responses. I was going to put new drywall over the existing,. I'm having a hard time sourcing QuietRock around here and have heard that it's quite expensive. I have read that a product called Green Glue Noiseproofing compound between regular sheetrock layers can work as well. Does anybody have experience with this product?
@Amy A., I used green glue between shared walls in my duplex. My method used was what Green Glue recommnded. Two 5/8" drywalls layers with GG in between. The glue is expensive and you also need to use their sealing compound for all the cracks around the drywall. I've read resilient channeling is a good option IF you have it installed right. From my understanding, GG works just as well as resilient channeling, may offer the fire rating you are looking for. If you look around on the web for GG versus resilient channeling, you may find a lot.
Another idea for soundproofing is to lay down high density rubber matting on the floor of the upper unit. This is really only practical when you turn it over and are already replacing carpets. It is expensive, but if the vacancy and headaches for you are worth the cost, both the GG and rubber matting sound like they will help you.
@Taylor McClung Did you notice an improvement when using Green Glue or do you wish you had used something else? Yes, I will try rubber matting with the next 2nd floor turnover I do.
I noticed some improvement. One of the biggest downfalls with the way I did it was that I did not install in on every wall dividing the units. Where it is, you can tell. Proper installation really is the key to either method you choose. I've heard quietrock is in theory the same principle as the GG. A layer of sound absorbing adhesive between or built into the material. I think the cost comparison is the same. GG can be shipped anywhere so for me, it seemed easier than finding a specialty distributor for the quietrock.
QuietRock and Green Glue are the standard for sound-proofing in professional music studios. The type of insulation is really important, too (check out OC 703 or Rock Wool insulation, instead of plain old pink insulation).
Thickness of material and airspace are critical for soundproofing. That's why sheets of OC703 are 3" thick of rigid material.
The "best" solution is a room-within-a-room, but that doesn't really make sense for residential applications. You build two walls, with insulation and air between them. That makes an enormous difference.
You can also get rubber floor insulation that goes underneath your tile/hardwoods.
And don't forget the power of furniture. A big couch can do wonders for changing the sound characteristics of a room. Carpet and drapes (thin and not rigid), not so much.
QuietRock and Green Glue are the standard for sound-proofing in professional music studios. The type of insulation is really important, too (check out OC 703 or Rock Wool insulation, instead of plain old pink insulation).
Thickness of material and airspace are critical for soundproofing. That's why sheets of OC703 are 3" thick of rigid material.
The "best" solution is a room-within-a-room, but that doesn't really make sense for residential applications. You build two walls, with insulation and air between them. That makes an enormous difference.
You can also get rubber floor insulation that goes underneath your tile/hardwoods.
And don't forget the power of furniture. A big couch can do wonders for changing the sound characteristics of a room. Carpet and drapes (thin and not rigid), not so much.
Don't forget that she need also comply with fire rating - which typically necessitates the use of dense Rock Wool (i.e Roxul Safe-n-Sound)in the cavity between units and often requires you hang fire-rated sheet rock from resilient channel.
@Amy A. Here is a link to Rock Wool's DIY video outlining a good soundproofing system. Their method usese good insulation (Rock Wool) resilient channeling, and two layers of drywall. I've seen the Green Glue substitute their glue for the resilient channeling. Either way, soundproofing, as I'm learning, should be thought through to maximize. There is no easy solution where you just do one fix and that's it.
Amy, have you decided which direction you're leaning to?
I'm going to try one room with Green Glue and a new layer of sheetrock and another room with quietrock over the damaged sheetrock. I'm not going to take the existing ceiling down to insulate. I'm going to compare the two rooms and see what works better. I'll post my results here!
@Amy A. - in my up/down duplex I had cellulose blown into the ceiling of the lower unit rather than take down the old ceiling that potentially had asbestos in it. I then used the J-channel to hang a new ceiling.
The main difference was installing a second gas furnace and separating all the duct work. Be careful about holes in your system. Electrical outlets and overhead lights can let sound through. Pipe penetrations are another way that sound can leak between units. Also cheap windows, single pane upstairs and single pane down stairs allows sound to go around the sound proofing.
@Amy A. - Did you end up installing the two different soundproofing materials? I have a shared wall in my duplex where noise can be a problem. Did you install the materials yourself? Do you mind sharing estimated costs?
With more research, we decided no to install quietrock because of the expense ($70 per 4 X 8 sheet) and many sites said that it's just like 2 layers of sheetrock with greenglue between them. So, I ordered the greenglue online and it was delivered within 2 days. He just put it up and so far no difference. I think that it still needs more of the caulking at the bottom of the wall (The special acoustical caulking that comes with green glue). He needs to get behind the hot water baseboards and caulk the bottom of the wall.
This process has been excruciatingly slow because my "contractor" has not been showing up regularly. Very frustrating!
I have the same question for shared wall between my one story duplex. It's down to the studs right now so when I put drywall up I really want to get the soundproofing right the first time. What did you end up doing and how did it go? This wall happens to be extra thick too so if I sent the roxul route I'd need at least two layers. Any feedback would be appreciated!
Is the dividing wall between the units a double wall? ... essentially, each unit has a wall with a space between them. In older construction, it is apt to be a single wall (perhaps 2x6). On a couple of occasions we have encountered concrete block/brick firewalls between units.
Dividing/Common walls are required to be fire rated - typically to 90 minutes. Around here that means 5/8" fire-rated drywall on both sides (in a double wall it is typically the face in each unit and one of the two faces between the walls ... for practical reasons) hung on resilient channel with fire-reated insulation/barrier in the cavities (like Roxul Safe-n-Sound).
The act of fire rating the wall assemble adds some sound proofing. If you make prudent use of acoustic sealant and/or hang a second layer of 1/2" drywall over the fire rated - with a liquid acoustic membrane (i.e. "green glue") or a {cork} matt between you can eliminate most of the sound from the other side.
thank you, Roy! This is very helpful. I probably have my terminology wrong but it's essentially two sets of 2x4s that have a few inches between them. So it's a substantial wall cavity, but not two separate walls. The duplex is 1930 so there is a lot of catching up to do. This info is very helpful!
thank you, Roy! This is very helpful. I probably have my terminology wrong but it's essentially two sets of 2x4s that have a few inches between them. So it's a substantial wall cavity, but not two separate walls. The duplex is 1930 so there is a lot of catching up to do. This info is very helpful!
Megan:
That is precisely what I was trying to describe and it is a typical double wall or common wall. Both sets of stud bays should contain a fire barrier insulation such as Roxul Safe-n-Sound or Safe and one of the two faces with the "few inches between them" may have to be drywalled (depending on local code). The space between the walls should also have fire breaks at each ceiling/floor assemble to prevent it from becoming a chimney. I usually fill this space with another layer of safe-n-sound.
The side of each 2x4 wall that is in a unit needs to have 5/8 fire rated drywall typically hung on resilient channel.
Roy, do you have any experience with QuietRock as opposed to resilient channel? The QuietRock seems very expensive but Resilient Channel seems like the sound dampening would be highly dependent on a perfect installation, which might be possible but just researching options.
We have used both. While Quetrock will work for sound proofing, and can be used for fire-rated assemblies (check to be certain your local building code will permit it), it is an expensive solution for fire rating. A properly fire-rated wall assembly is most important ... you can achieve adequate sound proofing in the process ... which is why I suggested a layer of acoustic membrane and another layer of {1/2"} drywall over the 5/8" fire-X drywall if you really need it.
Installing resilient channel (with or without spacers) is fairly easy {just be certain not to hang it upside down} and provides a good break for low frequency sounds. Once the channel is across the studs, you hang your drywall vertically on the channel.
Got it, yes, I'd prefer to achieve both. Safety is first priority.
How do you think the soundproofing would be if I just used the Roxul Safe n' Sound, plus resilient channel, plus 5/8" fire-x drywall? I'm just trying to balance everything (including cost) and I don't want to overdo it.
Again, thanks for taking the time to answer these questions. This is new to me so I truly appreciate it!
If you fill the stud bays with safe-n-sound, drywall the backside of the opposite wall; {optionally} fill the cavity between the walls {loosely} and then use channel and fire-x on wall spaces in the living spaces you will have descent sound deadening.
Check with your building inspections department or fire marshall to see if you have local requirements which differ from the IRC/IBC when it comes to fire-rating common walls.
i used it in ceilings and in the walls and it worked great.
i also had lowered/tiled ceiling, so i could remove it easily in order to spray the foam.you may have more difficulty trying that. For the walls i just drilled small holes and filled the cavities.
i used it in ceilings and in the walls and it worked great.
i also had lowered/tiled ceiling, so i could remove it easily in order to spray the foam.you may have more difficulty trying that. For the walls i just drilled small holes and filled the cavities.
But you cannot use open cell foam in a fire rated wall assembly.