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How to Reduce Sound Transmission Through Walls

Architects, developers, and contractors that build residential apartments, townhouses, single-family homes, and commercial office properties are largely concerned with keeping costs as low as possible without sacrificing quality.

Historically, the designers and builders have not given enough attention to the “soundproofing” of walls because there was a lack of cost-effective products and solutions. The reality is that walls are typically constructed as inexpensively as possible with shared walls being made from little more than 2×4 studs, a layer of drywall on each side, and some cheap fiberglass batt insulation.

When residents and tenants are surveyed on the perceived noise transmission from the walls detailed above, most individuals describe them as being “paper thin”.


Sound Transmission: A Frustrating Struggle

Your home is your castle and your bedroom is supposed to be a relaxing oasis. But what happens when that oasis is interrupted with the drumbeat of footsteps overhead, the nuisance of a TV blasting from your neighbor’s apartment, or the screaming of children that aren’t even yours?

From single family homes to apartment complexes, duplexes, hotels, and even offices…the reduction of noise transmission can transform a space into a more relaxing and more productive environment.

If noise is keeping you, or your tenants awake at night, read on to learn about the steps you can take to “soundproof” your home, apartment, hotel, condo or office space.


Why is Noise Such an Issue in Buildings and Homes?

Two words: Building Codes.sound testing meter on stand

There are very few mandated construction requirements in the Uniform Building Code (UBC) or International Building Code (IBC) with regards to noise. Not to mention updates to the code happen only once every three years, with individual states lagging far behind that.

International Building Code 2006 states that separation between dwelling units and public and service areas must achieve STC 50 (STC 45 if field tested) for both airborne and structure-borne. However, not all jurisdictions use the IBC 2006 for their building or municipal code.

For example, in 2009, the majority of states were still using the 2003 version of the UBC/IBC. As of the 2003 version, those walls which are “shared” are required to have an STC rating of at least 33.

We won’t get into STC ratings (learn more here) but trust us when we say a rating of 33 does VERY LITTLE to block the transmission of sound.

Worse yet, this “minimum” STC rating is only applicable to “new” construction, meaning many homes, apartment complexes, hotels and other buildings constructed before that date are usually much worse off.


Understanding How Noise Travels

Don’t worry, we won’t get too technical here, but having a basic comprehension of how sound travels can provide you with some perspective on how to effectively reduce noise transmission through existing walls during your next remodel or renovation.

And now, a brief lesson on acoustics…

There are two basic types of sound: airborne and impact. That sound which is airborne travels, you guessed it, through the air. Impact noise are the vibrations transmitted through a structure, such as banging on a wall or the vibrations/impact from footsteps (often referred to as footfall noise).


The Challenge

Sound waves tend to travel along the path of least resistance, often making it difficult to accurately identify from where the sound is originating. For example, noises could be slipping through under a door, through HVAC ducts, or simply through poorly insulated walls.


Reducing Sound Transmission Through Walls

Walls rank among the top three structures commonly cited as sources of sound transmission. This is especially true when speaking about the adjoining walls between hotel rooms, apartments and condo units. These walls are often referred to as the party walls.

Let’s take a look at some strategies for reducing sound transmission through walls. We’ll divide these options into “construction” and “alternative no-construction” methods.



  1. Noise reducing drywall

Noise-reducing drywall (such as QuietRock) utilizes dual layers of gypsum that are separated by a viscoelastic polymer layer, all of which is designed to absorb sounds that would have otherwise transmitted from one room to the other.

  1. Layer Up

Not interested or able to tear apart the walls to replace them with noise reducing drywall? No problem. A fast, more affordable option is simply to add a single layer of standard ½” or ⅝” drywall right over the existing walls. This can effectively increase the STC rating of your walls by up to 6 points.

  1. Insulate Interior Walls

The right insulation can reduce vibrations that allow unwanted noise to pass through a wall assembly. Use insulation with higher STC and NRC ratings.

  1. Sound Dampening Tiles or Panels

Depending on the room and design, sound-dampening tiles may be an option. These tiles and panels are not generally made for aesthetics or suitable for living spaces but might make sense for commercial offices, coworking spaces and conference rooms.

  1. Doors

The doors causing the most problems are typically found in hotels and multifamily living spaces but often times it’s not the door that’s the problem…it’s the air gaps around the door. To help resolve this problem, the proper door sweeps should be installed.

  1. Sound Isolating Clips

If you have access to the underlying studs of the wall, sound isolating clips can be used to help physically transmitted sounds from traveling through the studs to the drywall.


Soundproofing walls without removing the drywall…

Construction and demolition is intrusive and costly, making the following alternatives a good option for any commercial property or homeowner seeking to reduce sound transmission through their walls.

  1. Soundproofing paint

That’s right!

Soundproofing paint such as that from SoundGuard is an innovative approach to sound reduction that is taking the industry by storm.

Why? Take a look at just a few of the benefits below:

  • Easy, spray-on application
  • Simple one-person process
  • Consistency of performance with every coating
  • Achieves a high degree of sound reduction
  • Increases the STC rating
  • Cost-effective
  • Non-invasive (i.e. no construction)
  • Eco-friendly
  • Mildew and mold resistant
  • Fire-resistant

As you can see from the above, soundproofing paint is a major hit with both commercial businesses and for residential applications.


  1. Sealing and Weather Stripping

Doors and windows can be a major source of sound transmission, but it’s not just the actual door or window that is the issue. Poorly insulated and sealed openings can be a major source of sound entering your rooms. Same goes for electrical outlets and vents/ducts. Weather stripping and acoustical caulk can be simple and cost-effective solutions to help.
Remember, if air can pass through or around it, so can sound.

  1. Soundproofing the Interior of the Rooms

If wall treatments or construction isn’t an option, there are still a few things you can do to help.

First up, soften the area. Sounds tend to bounce off of and through hard materials (especially those with broad flat surfaces like glass, tile, hardwood, etc). Consider adding carpet, soft furniture, and window accents like thick curtains.

How to Reduce Noise Between Rooms – Recap

Noise can be downright frustrating. But by following the tips in this guide you can be well on your way to establishing a quieter more peaceful and private space for you, your family or your tenants.

Recap of Options:

Noise reduction should be a consideration beginning with the planning, budgeting, design and construction process. When this isn’t an option (as with existing construction), steps can be taken to re-enforce the stability and insulation of the wall in order to reduce transmission of sounds. Though more invasive and costly, these methods are highly effective.

When construction is too expensive or not an option, soundproofing paint represents one of the best alternatives to explore. Products such as SoundGuard provide superior noise reduction and insulation at a fraction of the price of construction, and are fast, efficient, and user-friendly.

Ready to Take Back Control of Noise Today?

Let’s face the facts, lightweight construction, multi-unit housing, open floor plans and a whole host of other modern influences all contribute heavily to making living and office spaces noisier than ever before.

Whether soundproofing adjoining walls in a duplex or hotel, or soundproofing the interior walls of single family homes, noise reduction can dramatically improve the usability and serenity of the space.