Sound 'proofing' a common wall

[Greg Peterson]

I have one 4' x 8' section of wall in my shop that I need to sound proof somehow. And by sound proof I mean significantly abate the passage of sound from my shop to the living room.

The only real complication is that the gas line from the meter runs along this portion of the wall and is snugged up against it so going with a thicker material is not the first option as I would prefer to not get into rerouting the black pipe.

Any ideas on what materials or techniques would help abate the noise?

[Sam Layton]

Greg,

How about attaching 2x2's to your wall, and notch for the gas pipe. Then insulate, apply 1/2" sound board, and 5/8" dry wall. Or, build another 2x4 wall with the gas pipe in between the two walls, insulate, sound board, drywall. With the two walls not touching will give you the best results. In my shop, I have 1/2" sound board, and 5/8" drywall, and it does a good job.

Sam

[Greg Peterson]

There is a valved branch in the gas line to the fireplace. I am thinking that enclosing the line completely is not a great idea in general, and that the valve likely can not be enclosed, much like an electrical junction box needs to be accessible.

[phil harold]

Actually the best performance for the buck would be

1. add another layer of sheetrock mass of the wall will stop a majority of the noise
2. provide as little space as needed around valve to operate
3. caulk all areas where sound may transmit thru , floor joists, wall plates, sill plate
4. if possible add another layer of sheetrock to interior wall using or not using sound resistant channel

Yes a a double wall would be nice but would not work in you situation

Also look for noise transmission come thru the ceiling or the floor

[Thom Sturgill]

Can you open the wall to install insulation? If so, stuff rock wool (not fiberglass) in the cavity and replace the sheet rock with that special stuff they make with a metal layer in the center. Run a bead of acoustic silicon along the studs before fastening the new wall covering.

If you can not open the wall completely, open pockets and spray low expansion foam into the cavity. This will need to be done above and below the firestops if any are in the wall.

[Sam Layton]

I agree Greg. However, depending on the situation and how the gas line runs, you could install an access door where needed. Just an idea...

Sam

[Scott T Smith]

I have a 400 horsepower diesel generator installed in one room of my shop, and as you can imagine it is pretty loud (so loud that when you're standing next to someone in the room with the generator running, you have to yell into their ear to be heard).

I took a three phase approach to sound deadening, and it has worked extremely well.

Phase 1 was to have open cell spray foam insulation sprayed into the 2 x 4 wall, almost filling the entire cavity.

Phase two was the installation of two layers of 5/8" thick drywall, with the flexible polyethelene sill plate foam installed between the first layer of drywall and the studs, and then between the first and second layers of drywall. This was installed on the walls and interior of the doors.

Phase three was the installation of 1/2" sound deadening board on top of the drywall.

It is extremely effective. In the bathroom adjacent to the generator room, you can hear a faint hum, but part of that is the vibrations coming through the slab. Most of that went away when I built and installed a three layer isolation gasket between the generator frame rails and the slab.

[Kevin Stricker]

The best way you are going to significantly reduce the sound is to build a second wall over the first with an airgap between the two. You can do some google searches on the subject, try home theater sound isolation. The big challenge is that sound is transmitted through the screws and studs, anything you screw onto your existing wall will have a minimal effect. You have to isolate the sheetrock from the existing wall. They do sell drywall clips that will allow you to hang new drywall on existing wall, but installation is tricky.

[Tom Hintz]

When I converted a spare bedroom into my office/studio for video work and dubbing I had a contractor soundproof the common walls. They stripped the original drywall, used common fiberglass insulation within the existing stud wall and then applied a special sound-reducing drywall. They also applied this special drywall to the inside surface of the door. Now if I am in the studio with the door closed I cannot hear the door bell less than 10 feet away and there are not background sounds picked up in video editing and dubbing. I can't find the invoice to see if they had a specific name for the drywall but will post that here if we can find it. I found out that the contractor moved back to Maine someplace when I tried to hire him for another job we had so I can't ask him.

[David Wong]

I do not have any personal experience with this product, but a sound reducing drywall product that is available at the blue big box stores is called "quiet rock". There is also an interesting product that works regular drywall called "green glue". Plenty of sound reduction info on both sites.

[Jim O'Dell]

Another product that might help some and has been around for a long time is Homosote. It is a drywall substitute used in commercial buildings and schools. I found out about it back when my main hobby was model railroading. This was cut and used as roadbed material over plywood so that the trains didn't sound so toyish when they moved. It muffled the sound quite a bit. Jim.

[David G Baker]

Simple solution, glue 2 inch rigid foam board to the existing wall. I would test it first by attaching it with a few screws to see if it actually deadens the sound as much as you need.

[Greg Peterson]

Thanks guys. I originally thought about using acoustical sheet rock. The rock wool is an excellent idea. And using a adhesive rather than screws or nails also is helpful.

Looks like big blue has a rock wool type product. The Quiet Rock or similar type sheet rock is still problematic. Perhaps they can special order some.

The other suggestions have their merits but would not work given the previously stated constraints.

[Peter Aeschliman]

I did some research on sound proofing a while back when a neighbor in my condo complex was complaining about noise. As you probably know, sound is transmitted through solid surfaces via vibration. What I learned is that screws themselves, which go into your studs, transmit a fair amount of vibration, and the large surfaces of drywall can act kind of like a megaphone. So the key is isolating the drywall screws from the studs. They sometimes do this by doing one layer of drywall as normal. They then install special metal clips that have a foam or rubber layer which deaden vibrations. A metal channel system is then fastened to those channels. Lastly, acoustic drywall is fastened to the channel and is mudded and taped as normal. Kind of a hassle but pretty thorough.

[Ken Deckelman]

I used the "Staggered Stud" method when I built my dividing walls. Basically a 2x6 bottom and top plate with 2x4 studs then the rock wool insulation which can be ordered through home depot. May not work for you unless you rebuild the entire wall.