How to Soundproof a Wall – Soundproofing Walls

Hearing neighbor noise through your walls? Mad at the builder for not building soundproof walls? Sorry to say it’s probably not the builders fault at all. North American Building Codes are not very helpful with noise levels. You do not have to build very soundproof walls to pass building code.

If you’re going to solve your noise problems coming through the walls, you’ll have to learn a little and do it yourself.

Ideally, when trying to reduce sound it is very advantageous to apply the soundproofing materials on the noise-producing side of the wall. However, if your neighbor is the noisy one, this would mean applying the soundproofing to his side, and generally noisy neighbors have no interest in helping. So you’ll have to treat your side.

One very important thing to keep in mind is the noise from your neighbor isn’t only pouring through your wall. Some amount of sound is flanking around that wall and also entering through the floor and ceiling.

Here is a basic list of approaches in order of effectiveness. Sound Transmission Class (STC) is a common measurement of sound isolation. A higher STC figure means more sound isolation.

Solutions #4 and #5 also have significantly better low frequency (bass) isolation. This makes them advantageous if music or sound systems are involved. Let’s take a look at each of these soundproofing solutions more closely.
stc-values-42

Soundproofing Walls Solution 1:

Add Extra Drywall to the Wall

In some construction situations just adding a second layer of standard drywall to your existing wall assembly is all that is required. The new layer of drywall brings added Mass (weight), which is one of the 4 Elements of Soundproofing. A heavier wall is generally a more sound isolated wall, which will improve soundproofing performance.
STC Source Side Studs Insulation Receive Side Test #
42 Two 5/8″ layers of drywall 24″ oc R13 One 5/8″ layer of drywall OL 05-1058
Ease and Cost Performance
Inexpensive
Simple
You can see from the test data above that this procedure would only yield an additional 2 STC points.
While audible, this improvement is minimal.

stc-values-44

Soundproofing Walls Solution 2:

Add Sound Deadening Board & Drywall
Sound-deadening board has been used for decades and is also sold under many trade names. It is a soft, fibrous board 1/2” thick and quite light. Generally tan or dark brown and found at building material centers. This is not to be confused with compressed fiberglass.

Sound boards or panels are very light, and therefore don’t contribute because of any addition of mass like the previous solutions. In this case, the lightweight sponginess offers a slight amount of Absorption (another of the 4 Elements of Soundproofing.) as well as minor Decoupling (yet another Element). Soundboard absorbs a little and decouples a little.

STC Source Side Studs Insulation Receive Side Test #
44 5/8″ drywall + 1/2″ Soundboard + 5/8″ drywall 24″ oc R13 5/8″ drywall Estimated
46 5/8″ drywall + 1/2″ Soundboard 24″ oc R13 1/2″ Soundboard + 5/8″ drywall OL 05-1056
Ease and Cost Performance
Inexpensive (sometimes)
Fast
Simple
This adds at least an inch of thickness to your existing wall.
You can see from the test data above that this procedure would yield an additional 6 STC points.The difference is audible and the improvement is moderate.

 

stc-values-45
add-mlv-assembly

Soundproofing Walls Solution 3:

Add Mass Loaded Vinyl & Drywall
Mass Loaded Vinyl is sold under many different brand names, but in essence all (including ours) are a vinyl rubber made heavier by loading with Barium. This extra mass combined with the new drywall make the wall’s much heavier and increases your walls soundproofing. This application will typically yield an additional 4-6 STC points to a wall.

STC Source Side Studs Insulation Receive Side Test #
45 1/2″ Drywall + MLV + 1/2″ Drywall 24″ oc R13 1/2″ Drywall OL 05-1054
Ease and Cost Performance
More expensive
More difficult due to MLV installation
Slower due to MLV
You can see from the test data above that this procedure would yield an additional 4-6 STC points.
The difference is audible and the improvement is moderate.

stc-values-52add-green-glue-assembly

Soundproofing Walls Solution 4:

Add Green Glue & Drywall
Adding Green Glue Soundproofing Compound introduces the last element of the 4 Elements of Soundproofing: Damping. Damping converts the vibration energy into heat energy. This is a very efficient process with great soundproofing results. This is also the most common soundproofing solution for retrofitting walls assemblies, due to its low impact installation process.

not-recommended

STC Source Side Studs Insulation Receive Side Test #
52 Two 5/8″ layers of drywall + 2 tubes of Green Glue per 4×8 sheet of drywall 24″ oc R13 One 5/8″ layer of drywall OL 05-0416
Ease and Cost Performance
Moderate expense
Fast
Simple
Adds only 5/8” thickness to your existing wall.
You can see from the test data above that this procedure would yield an additional 12 STC points.The difference is quite audible and the improvement is significant.Low frequencies show improvement.Flanking Noise is reduced.

stc-values-66
Whisperclip Wall Assembly

Soundproofing Walls Solution 5:

Add Resilient Clips, Channel, Green Glue & Drywall
This Solution is the highest performance and most definitive. It requires the removal of the existing drywall.

The most dramatic improvement from this technique comes from the introduction of competent decoupling via the use of Sound Isolation Clips and Drywall Furring Channel. This solution incorporates all 4 Elements of Soundproofing. You have Decoupling, Absorption, Mass and Damping. Certainly the most labor intensive, it is also far and away the most thorough solution.

  • Allows you to seal the backs of his wall outlets from your side.
  • Allows you to add standard R13 fiberglass if there is no insulation currently.
  • Allows you to seal other openings and penetrations with Putty Pads.
STC Source Side Studs Insulation Receive Side Test #
61 Two 5/8″ layers of drywall + 7/8″ Drywall Furring Channel @ 24″ OC + WhisperClip 24″ oc R19 One 5/8″ layer of drywall OL 08-0712
66 Two 5/8″ layers of drywall + Green Glue (2 Tubes per 4×8 sheet) + 7/8″ Drywall Furring Channel @ 24″ OC + WhisperClip 24″ oc R19 One 5/8″ layer of drywall Estimated
Ease and Cost Performance
More expensiveAdds almost 3” thickness to your existing wall.Requires removal of existing drywall. This procedure would yield an additional 21 STC points.The difference is very audible and the improvement is very significant.Low frequencies show significant improvement.Flanking noise is reduced.

Summary

Solution STC Source Side Studs Insulation Receive Side Test #
Ref. 40 One 5/8″ layer of drywall 24″ oc R13 One 5/8″ layer of drywall OL 05-1003
#1 42 Two 5/8″ layers of drywall 24″ oc R13 One 5/8″ layer of drywall OL 05-1058
#2 44 5/8″ drywall + 1/2″ Soundboard + 5/8″ drywall 24″ oc R13 5/8″ drywall Estimated
- 46 5/8″ drywall + 1/2″ Soundboard 24″ oc R13 1/2″ Soundboard + 5/8″ drywall OL 05-1056
#3 45 1/2″ Drywall + MLV + 1/2″ Drywall 24″ oc R13 1/2″ Drywall OL 05-1054
#4 52 Two 5/8″ layers of drywall + 2 tubes of Green Glue per 4×8 sheet of drywall 24″ oc R13 One 5/8″ layer of drywall OL 05-0416
- 61 Two 5/8″ layers of drywall + 7/8″ Drywall Furring Channel @ 24″ OC + WhisperClip 24″ oc R19 One 5/8″ layer of drywall OL 08-0712
#5 66 Two 5/8″ layers of drywall + Green Glue (2 Tubes per 4×8 sheet) + 7/8″ Drywall Furring Channel @ 24″ OC + WhisperClip 24″ oc R19 One 5/8″ layer of drywall Estimated

Independent tests were conducted by Certified NVLAP acoustic laboratories.