THE NOT-SO-PRIVATE OFFICE
PROJECT BLOG
SOUNDPROOFING
COST CALCULATOR ›

How to Soundproof Walls and Ceilings

Soundproofing Walls and Ceilings is normally performed to stop unwanted sounds from entering the room, or to prevent sound from leaving the room into adjoining spaces, either to resolve noise complaints or to provide privacy for those in commercial, office, or residential rooms.

Soundproofing that works requires more than one approach to be successful.

Three different principles of soundproofing will help make a wall or ceiling perform and stop most sound from entering or leaving the room.

Decoupling

One of the most important principles of soundproofing is “decoupling”, which means to separate one surface from another in such a way that the vibration of one of them will not impact the other. Decoupling a wall or ceiling can be done in several ways. The most budget-friendly solution for decoupling depends on the original wall construction, the space available for the wall, and the soundproofing goals that you are trying to meet.

Decoupling can be achieved by using resilient channel, or by adding wall framing parallel to the existing wall. Importantly, a decoupled wall should only have one air cavity in-between the two sides of it.

Increasing Mass

Sound waves will be slowed and stopped when they encounter a large amount of mass that absorbs sound waves themselves and does not reverberate. Adding layers of mass loaded materials such as mass loaded rubber, are an effective way to increase the total mass of the wall, and increase the amount of sound transmission loss created by the wall.

Similarly, adding layers of drywall can be highly effective at stopping sound, but this will be highly impacted by how it is installed. For example, four layers of drywall rigidly applied to a masonry surface will not block a lot of sound, whereas two layers of drywall with a viscous compound in between them and decoupling with metal framing in-between it and the original wall behind it, will

Adding sound absorption

Sound absorbing materials within a wall, when installed in combination with decoupling and mass loaded materials, have a significant impact on sound transmission through the wall. The most common material used is rockwool insulation, and it is a key component of any wall that provides effective sound attenuation.

Sealing all weak points and gaps

Walls with holes and gaps, even as small as 1mm, will transmit a large amount of sound through it despite any soundproofing that has been installed. Masonry walls are particularly vulnerable to this failure point.

Electrical outlets, switches, and lights, especially pot lights, are common failure points that should be sealed to prevent sound transmission through the wall.

Similarly, sealing all the corners and joints of drywall with acoustic sealant before any taping and plastering is completed is also extremely important for the sound attenuating performance of the wall.

Installing Soundproofing Drywall or Layers of Drywall With Soundproofing Compound

For single drywall layer installations (not thicker than 5/8″), soundproof drywall is a highly effective solution for the final layer of wall facing the room. The drywall must be sealed with acoustic sealant, drywall tape and plaster to provide effective soundproofing results.

Where multiple layers of drywall can be installed, 2-4 layers of drywall with a viscous soundproofing compound can be added to the wall to maximize soundproofing performance.

Common wall and ceiling assemblies and their STC Ratings

Wall Construction Type Component Layers STC Rating Sound Experience
Residential Timber Wall with Drywall 2″x4″ lumber
1/2″ drywall on both sides
Tape and plaster
25-30 Conversations and common noises fully audible
Residential Fire Rated Timber wall with Drywall 2″x4″ lumber
Sound and fire insulation
5/8 Type X drywall on both sides
Tape and plaster
35 Conversations and common noises muffled but audible. Loud noises fully audible.
Residential Fire Rated Timber Wall with Insulation and Double Drywall on Both Sides 2″x4″ lumber
Sound and fire insulation     5/8 Type X drywall on both sides
Tape and plaster
41 Moderate sounds blocked, loud conversations barely audible and unintelligible
Residential Fire Rated Timber Wall with Insulation, Resilient Channel on One Side, Fire Rated Drywall on Both Sides, Care taken for All Flanking and Acoustic Sealing Considerations 2″x4″ lumber
Sound and fire insulation
Resilient Channel on One Side
5/8 Type X drywall on both sides
Tape and plaster
51 Normal and moderate sounds blocked
Loud sounds and conversations somewhat audible and intelligible
Residential Fire Rated Timber Wall With Insulation, Fire Rated Drywall on One Side, Fire Rated Double Drywall and Green Glue on One Side, Care taken for All Flanking and Acoustic Sealing Considerations 2″x4″ timber
Sound and fire insulation
5/8″ Type X drywall on One Side,
Two Layers of 5/8″ Drywall on One Side with Soundproofing Compound
Acoustic Sealants and Putty
Tape and plaster
53 Moderate sounds blocked, loud sounds barely audible and unintelligible
Residential Fire Rated Timber Wall with Insulation, Resilient Channel on One Side, Soundproof Drywall on One Side, Fire Rated Drywall on One Side, Care taken for All Flanking and Acoustic Sealing Considerations 2″x4″ lumber
Sound and fire insulation     5/8 Type X drywall on both sides
Tape and plaster
55 Moderate sounds blocked, loud conversations barely audible and unintelligible
Commercial Typical Office Steel Wall 2″x4″ steel
1/2″ drywall on both sides
Tape and plaster
37 Conversations and common noises fully audible
Fire Rated Office Steel Wall with Insulation and Fire Rated Drywall on Both Sides 2″x4″ steel
Sound and fire insulation
5/8″ Type X drywall Both Sides
Tape and plaster
 40 Moderate sounds blocked, loud sounds barely audible and unintelligible
Fire Rated Office Steel Wall With Insulation, Fire Rated Double Drywall on Both Sides, Care taken for All Flanking and Acoustic Sealing Considerations 2″x4″ steel
Sound and fire insulation
Double Layer of 5/8″ Type X drywall on Both Sides Side,
Acoustic Sealants and Putty
Tape and plaster
 50 Moderate sounds blocked, loud sounds barely audible and unintelligible
Fire Rated Office Steel Wall With Insulation, Fire Rated Drywall on One Side, Soundproof Drywall on One Side, Care taken for All Flanking and Acoustic Sealing Considerations 2″x4″ steel
Sound and fire insulation
5/8″ Type X drywall on One Side,
Two Layers of 5/8″ Drywall on One Side with Soundproofing Compound
Acoustic Sealants and Putty
Tape and plaster
52 Moderate sounds blocked, loud sounds barely audible and unintelligible
Fire Rated Office Steel Wall With Insulation, Fire Rated Drywall on One Side, Resilient Channel One One Side, Soundproof Drywall on One Side, Care taken for All Flanking and Acoustic Sealing Considerations 2″x4″ steel
Sound and fire insulation
5/8″ Type X drywall on One Side,
Two Layers of 5/8″ Drywall on One Side with Soundproofing Compound
Acoustic Sealants and Putty
Tape and plaster
54 All Low to Moderate sounds blocked, loud sounds barely audible and unintelligible
Fire Rated Office Steel Wall With Insulation, Fire Rated Drywall on One Side, Fire Rated Double Drywall and Green Glue on One Side, Care taken for All Flanking and Acoustic Sealing Considerations 2″x4″ steel
Sound and fire insulation
5/8″ Type X drywall on One Side,
Two Layers of 5/8″ Drywall on One Side with Soundproofing Compound
Acoustic Sealants and Putty
Tape and plaster
56 Moderate sounds blocked, loud sounds barely audible and unintelligible