I have a side by side duplex over a concrete basement with the main supporting beam dividing the sides. Below the beam and between support columns is a non bearing 2X4 wall with open bays on one side and ship lap on the other side. To mitigate noise (source of tenant complaints), I would like to add materials to reduce sound transmission. My plan is to add unfaced fiberglass to the bays and screw 5/8 drywall onto the open side. Any easy adds to improve performance?
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There have been several other posts re this, but to put in some ideas -
It is best to have no way for sound to transmit thru the structure, obviously. sometimes 2 separate walls are req'd, but since you want to be cheaper, then go with the batts plus 2 thicknesses of 1/2" drywall with resilient bar. People differ in their opinions, my preference is to hang the first layer, then screw the res-bar at rightangles to the studs, then screw (with short screws) the second layer of board to the res-bar. Each side of the walls.
Do not allow any of the finish materials to touch the posts and beam if you can help it
To those who know - this may be obvious. To those who don't - I hope I've helped.
Helpful. Thanks! Since we're (you're) on a roll... Any helpful hints about the type of blow in insuulation to spec for the common wall on the main and second floor of the same property. Lath and plaster construction.
Insulation isn't really the answer to sound deadening. The STC (Sound Transmission Coefficient) of assemblies (walls, windows, doors) go up as their mass increases, and as "uncoupling" layers are introduced.
A newly-built studframed wall of offset 2x4s built with 2x6 plates, with every other stud offset to the opposite wall, is a good way to deaden sound. So is the use of RC channels as an uncoupler in fastening drywall.
A relatively cheap way to add mass to an existing wall is to throw on another layer of gyprock.
Here is a great example of uncoupling in action. The large glass window walls you walk by in a typical big airport concourse are sheeted in laminated glass. Go down the stairway and out the door to an outside ramp and see how noisy it is out there, and how well that laminated glass deadens the noise, with its flexible plastic inner layer.
I forget where I just read this, but in oneof my mags, I read where USG has developed a new drywall sheet product for sound. The sheet is only 5/8 thick, but is equivalent to EIGHT sheets of drywall.
The upside is that this new product is 5/8 thick and doesn't take up much room...the downside is cost...approx $80 per sheet! If you only need a few sheets then have your lumberyard order it for you...this stuff is supposedly now on the market.
Just a thought
Davo
Standard fiberglass insulation is not a particularly effective sound damper in this type of situation. There is a special type of fiberglass insulation that is made for sound dampening. I have not looked into it, but I assume it is fiberglass insulation in which the strands are coated with something that better absorbs the sound insulation. You can probably find something about it with a Google search. However, there are other types of materials that are probably stocked by your local lumberyard that will be more effective than the regular fiberglass stuff.
As was mentioned, there have been many discussions of sound deadening on Breaktime - I would guess at least one every month or two. The search feature on Breaktime can be somewhat frustrating to use and require choosing just the right search terms, but you should be able to get lots of inforation that way. The last discussion on the topic was a couple of days ago at 63237.1
I don't understand your discription - "open bays on one side and ship lap on the other side" - regarding the divider wall but...
Do not use the reg pink fiberglass insulation. Mineral wool is better. There is a fiberglass material (yellow) which is called sound isolation barrier, but I still prefer the mineral wool.
Frankie
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FWIW, I was told by my insulation man to use rockwool as well. I intended to, but finally got around to hanging the drywall in front of some noisy retrofit ductwork on a weekend. Since the drywall place (that sells the rockwool) was closed, I bought pink stuff from HD. It did say something about noise deadening on it, but did not look any different than standard batts. hanging that & drywall has reduced the noise by 90%.
LEW
Screw rollformed steel RC ("resilient channel") to the studs, and then hang your rock.
Frankie and Stinger are correct, use sound barrier insulation ( rotten cotton),found at gypsum board supply house. Resilient sound channel and acoustical caulk are also found same supply house. If all three are used , the noise transmitted will be much less. The caulk goes on the top and bottom plates before they are installed. Do a google search for installing the RSC metal, the websites describe it better than I.
mike
Rip the fiberglass in half so it half the thickness, then cut a piece of drywall to fit in the bay between the 2 FB layers. The fiberglass just helps keep the dw board from touching anything else.
I second the motion for rock wool (aka mineral wool). I used it in my house. Works very well.
I have looked at doing the same thing for a theater room we are adding. The drywall product is QuietRock from Quiet Solution. After talking with the rep, I scaled back the use to only the 2 walls connected to the house, as the product is expensive. Approx. $90 per sheet (4'x8'). But it gets the job done and does not require additional framing. Their website has alot more information about it. I found this product in the past issue of FHB.
Yep, and I've used it .
Even the skeptical foreman admits that there might be some B.S. involved in their spiel, but it's not all B.S. The stuff does damp the noise and you don't need a two foot wall or a sheet of lead.
NotAClue
Glad to hear that. If it weren't so expensive probably would have just done the whole room in it. But will use some of the savings to use sound reducing window & door in the room. I have tried to understand all the technical information they give you but am not sure I get it all right, so I keep asking them for explanations and am usually satisfied by the answers.
I'm going to try this on my theater room.... guys that put those huge bang'n sound systems in cars use a ton of what appears to be nothing but waterguard the self sticking roll roofing material... I've used torch down on stainless sink bottoms... on the sides of dishwashers ect... long before they had the self stick roofing materials...
my thoughts are... cover the back side of the rock before it's screwed up... or come in from the backside and put it between studs or option 3 put a layer of rock... a layer of the roofing then more drywall..... even considered strips just on the studs...... any thoughts on this?
should add about what equals to $15 a sheet to the drywall
i might have said this before... but i did see a guy building a studio once that put a saw cut down the center of every 2x6 stud except for the top & btm 3-4 inches he said it was as good as double studs..