Common Walls: Related Q&As
Back
How does noise bleed through a common wall?
The human ear detects airborne sound waves, but a common wall transmits structure borne sound waves. Sound emitted from one side of a common wall will convert from airborne to structure borne energy, vibrate through the common contact points in your wall, and become airborne once again on the other side. The wall itself will ebb and flow, much like an eardrum, resonating to the frequency of the original sound. By lining the common wall with weight, and adding a disconnection into the assembly, you can impair the walls ability to conduct vibrations, and force the collapse of the wave inside your wall.
Does stuffing fiberglass insulation in my walls help block noise?
This will have very little effect on your treatment. Anything you stuff "between" the wall studs is ignoring the essential path the noise is taking, which is the studs themselves. Insulation creates neither a disconnection in your wall, nor does it add any density to the surface.
What does STC mean?
This stands for Sound Transmission Coefficient and is covered in more detail in the STC section of our NetWell Academy. Essentially it is a rating system that measures a wall assembly's ability to combat the bleed of sound. A standard studded wall with drywall on both sides will deliver an average STC rating of 38. A luxury grade wall will carry an STC rating of 55-60 or greater. Again, these walls will be designed to impair vibration through the use of density and disconnection.
How do I block noise from bleeding through my wall?
Line the common wall with more density, and disconnect the common structure. Your treatment option depends on your starting point, as we outline here in the Walls section of our website. Your goal is to impair the walls' ability to conduct vibration, and force the collapse of the sound wave. We design treatments for new build, existing frame or finished wall systems.
Do I need to tear down my existing wall?
No. We will add material to your existing surface to help slow the rate of vibration and disconnect the structure from the opposite side of the wall. Keep what you have, just add to it. Treatments can add as little as 1.5" of depth to your existing wall surface, and trigger up to a 90% drop in sound bleed.
What is mass loaded vinyl?
Years ago it was common to place lead sheets inside walls to help combat the bleed of noise. For environmental safety concerns, lead was replaced with mass loaded vinyl. This is the equivalent to a thin rubber tarp that is layered beneath your drywall to help deaden your wall's ability to vibrate. dB-Bloc is NetWell's mass loaded vinyl. It measures just 1/8" thick, yet weighs more than 150 pounds per 54" x 30' roll. Cover 100% of your common surface with this sound deadening material. The material is stapled or screwed to your existing frame or finished drywall. Then simply drywall over the top to conceal the material permanently within your common wall assembly.
What does it mean to disconnect my wall?
As we teach in our course on Sound Transmission, the studs in your wall serve the same purpose as a string pulled tight between two coffee cans. This improvised telephone system worked well when you were a child, because the string was delivering structure borne sound waves back and forth. The studs in a wall serve the same function. If you were to take a scissors and cut the string, the improvised phone would fail as the wave would collapse. The studs in your wall also require the disconnection. We outline several disconnecting options for you here in the Walls section of our website.
What is Green Glue?
Green Glue is a new substance that is applied between two layers of drywall. The treatment will require you to double drywall your surface, and apply Green Glue with a caulking gun as a constrained layer sandwiched between your two layers. Green Glue destroys transmitting energy by impairing the walls ability to conduct vibration.
What is sound damping?
Damping is the process of slowing vibration. The more your wall is able to conduct vibrations, the more it will bleed noise. By lining your wall with more weight and triggering your disconnection points, or by applying GreenGlue with a double drywall application, you impair your wall's ability to conduct vibration, and force the collapse of the transmitting sound wave.
What are resilient channels?
These are horizontal metal channels that can be anchored over dB-Bloc to help give your final drywall layer a surface to attach to that is disconnected from the vertical studs inside your wall. This treatment is popular for existing walls where double wall or staggered stud assembly's are not possible. Wooden firring strips can serve the same disconnecting function as a metal channel system.
Does pre-engineered drywall work?
Yes. But remember that a 4'x8' piece of pre-engineered drywall can cost $120, while a regular sheet of drywall might cost $8. This makes for an expensive treatment, not to mention a costly pile of scrap drywall that gets tossed. Regardless of standard or pre-engineered drywall, the framing structure will still need to be disconnected. Mass loaded vinyl with standard drywall is easier, less expensive and triggers equal or better results. In addition, hanging pre-engineered drywall that requires a saw to cut through it will create a more labor intensive work load than anchoring dB-Bloc and standard drywall to your assembly.
Show me more
What's the least costly way to treat my finished wall?
Line with dB-Bloc, apply a set of horizontal firring strips, and then a layer of drywall to the face of the firring strips. Your other lower cost option would be to apply GreenGlue to your existing wall and drywall over the top of it.
What should I do if I have an existing framed wall?
Staple dB-Bloc to the frame, apply a set of horizontal firring strips, and anchor your final drywall layer to the face of your firring strips.
What should I do if my wall isn't yet built?
Think ahead and construct a disconnected frame with either a double wall or a staggered stud wall. Both assembly options are featured here on this website. Then anchor dB-Bloc to the frame and drywall over the top.
Does double drywall help block noise?
Any additional density you add to a surface can help impair vibration, yes, but double drywall is only a piece of your puzzle. First, you need to disconnect your structure before or after your initial layer of drywall through the use of firring strips, resilient channels, staggered studs or double wall framing. Then you need to add more density, and double drywall will help. However, dB-Bloc is just 1/8" thick and will weigh more than your drywall, which means it is even greater in terms of density and will trigger a stronger STC rating than a second layer of drywall will. Also, remember that your best bet at combating sound bleed is to vary the thicknesses and the densities of the surfaces you are using. By layer two drywall sheets atop one another, the second layer is attacking the same frequency pitch of sound as the first layer. By placing thinner or thicker material up, you attack varying frequency pitches, and trigger a more favorable drop in sound bleed. So if you choose to double drywall, separate the sheets with firring strips, line with dB-Bloc, and finish off with a different thickness and you've got it!
Why do I hear more low bass tones through my wall?
Lower pitched tones have longer flatter sound waves which travel through less distance and time to pass through a common surface. It is easier for this wave to transmit through than a higher pitched tone for this reason.
Which side of the wall should I treat?
Ideally you want to treat the source side of the wall. Bring the treatment closer to the original sound wave. This does not mean that treating the opposite side of the wall won't help, it will. Anywhere you can trigger a disconnection and line with density to impair your wall's ability to conduct vibration, the better. Our goal is to force the wave to collapse, which can be triggered from treating either side. But deadening the vibration of the wall would play better if it were the source side of your wall.
Do you guarantee results?
No. Although we have thousands of clients spread around the globe who have enjoyed the results of these treatments, each individual wall and room assembly is unique. Each client we serve has a unique set of structural contact points and open air holes for noise to bleed out and cheat the system. While we know how well these treatments work in a laboratory setting where we can control all the variables, once we move the product mix to your site, we lose control of these variables. You will not get a 100% drop in sound bleed. No treatment, no resource, will ever deliver that result let alone guarantee it. However, if you follow our advice and the treatments outlined here, you could experience up to a 90% drop in sound bleed.
For further information on treating a common wall for sound bleed, read through the balance of this website or call our help desk at 1-800-638-9355. Good luck!