Soundproofing a Wall

Soundproofing walls is a common theme when looking to isolate noisy areas from those requiring more concentration or complete silence. While no wall assembly will ever be completely “soundproof”, you can attain very high levels of sound-blocking, measured in values of STC (Sound Transmission Classification). Many condo associations and building codes require a minimum STC of 50 between adjacent units, or between a living space and public area. While this will allow the developer to meet the bare minimum, this will often-times result in unhappy tenants if the units are near a busy road or other noise source.

Below, find our approach when assessing a wall, and determining the extent and method by which we soundproof it.

First, investigate the following elements of the wall.

  1. Studs: these are often wooden 2x4s or steel or aluminum channels that are easy to drill into, but offer enough support for the drywall to hang off of. Determine the type of studs you have, the size, and the spacing – 12 inches on center (which means center-to-center) is common (written as 12” o.c.). You will also find stud spacing at 18” or 24” o.c. for older homes. Greater stud spacing makes the wall less rigid, which means is transmits less structure-borne noise, but may transmit more air-borne noise. Similarly, metal channels are more flexible in the wall, and will reduce noise transfer.
  2. Batting: a standard batting in walls is R-9 or R-11, all the way to R-60 or higher. The R value only reflects the thermal insulation of the batting, rather than the sound insulation, but there is some correlation between the two. Determine the thickness, width, and type of wall insulation batting being used. Above all, having batting is critical to increase the decibel blocking of the wall. If drywall is already attached, you can still drill a hole and use blown-in insulation.
  3. Wall Type: the most important element of a wall’s sound-blocking capability are the two (or more) layers of the wall, one on each side of the studs. Determine what type of material these wall layers are composed of, their thickness, and how they are attached to the studs. Most commonly you will see 5/8” thick gypsum board screwed directly into the studs.
  4. Other Considerations: do you have any soundproofing elements already incorporated in your wall? These would include a Wall Blokker-type material or mass loaded vinyl that increases the weight of the wall. You may also have isolating rails or spacers, or occasionally resilient clips (metal clips that allow the drywall to hang off of the studs by an inch or so). Also, be sure to investigate sound leaks, especially holes around ducting, electrical installations, or other small perforations that allow large amounts of sound to leak through the wall.

Next, determine “how soundproofed” you need the wall to be. Within an office area, you may find that an STC 35-40 wall is sufficient to diminish noise between adjacent offices, while a home wall may need to be 55-60 to block noise coming off a busy roadway. Classified discussions and home theaters will often require STCs of 65 or higher. Whether you’re trying to muffle conversation or achieve complete privacy, there are a number of options to meet your STC requirements. Once you’ve identified the level of sound-blocking you need, you can begin treating the wall in question.

Finally, determine how to soundproof the wall. Soundproofing a wall is all about 2 variables: how much mass can you add to the wall, and how well can you float the wall from all adjoining surfaces (perpendicular walls, floor, ceiling, adjacent wall layers, etc.).

  1. Adding Mass to Soundproof a Wall

Soundproofing ultimately boils down to the Mass Law – the sound traveling through a medium is inversely proportional to the mass of the medium. Therefore, focus on adding mass to the wall in order to reduce the noise passing through it.

  • Increase the size and amount of drywall

And remember, you don’t need to use drywall. If you’re in a garage or other isolated environment, plywood, medium density fiberboard, or other wall coverings may also do the trick just fine. This is a balance between functionality, cost and aesthetics. We suggest at least 5/8” thick drywall, and if possible, adding a second layer on top of that. You will get diminishing returns with each layer of drywall (i.e. a 2nd layer will not block twice as much), but you will still notice the difference.

  • Add another element to the drywall

Adding mass to the drywall may also be done with a number of after-market products, designed specifically to go under drywall or directly on top of it. By installing beneath existing drywall, you can focus more on the functionality, and not need to worry much about aesthetics. Examples of this are the Wall Blokker, Wall Blokker Pro, and OverWall Noise Blokker.

There are also special types of acoustic drywall on the market with dense cores that will offer additional weight per square foot. Although these typically run at a high cost per square foot for material and installation, they are relevant in some commercial and industrial applications.

  • Add insulation within the drywall

Lastly, it is critical to always maximize the amount of insulation you can fit in the wall cavity. Be sure to fill all remaining voids in the cavity with excess insulation. This insulation should have a high R-value, although any insulation will do much better than none at all. There is some acoustically rated insulation batting on the market, including the QuietFil.

  1. Separating Wall elements to Soundproof a Wall

While adding mass is extremely effective at blocking airborne sound, you will also need to separate wall elements in order to attenuate structure-borne noise (i.e. vibrations). In the same way that a double-pane window has a vacuum between 2 panes of glass, a wall surface can be separated from an underlying layer so that sound cannot vibrate through the wall.

  • Adding a Resilient Channel, such as DecoupLink, can allow you to “float” the drywall on a flexible channel that absorbs vibration.
  • Using Staggered Stud design: By staggering the studs along the floor baseplate, neither stud will actually touch both drywall boards simultaneously. This creates a gap that insulates from structure-borne noise. This is a feasible option for new construction, but does reduce the room size by up to 4”.
  • Installing Wall Blokker Pro: this product is engineered to decouple between adjacent drywall layers, while also adding mass.

 

By adding mass to the wall and decoupling layers, you can attenuate both airborne and structure-borne noises. During installation, be sure to watch for unwanted and unanticipated gaps that arise. Installation for complex projects often requires a professional.

Overall, sound-blocking is not a black magic consisting of throwing more mone and materials Soundproofing can be so poor nowadays because construction often sacrifices material costs to keep total project costs down. While care is taken to improve aesthetics for “luxury” apartments and condos, they often have far less than ideal acoustics. Contractors, architects, and DIY’ers may review our case studies and white papers to further determine the most effective path to superior soundproofing.

Call today for a free site consultation or additional information on any of our products.

Soundproofing and Acoustics – Warehouse Renovation and Conversion

Commercial Acoustics provides expert soundproofing and acoustic advice and products for a variety of businesses. Here’s a look at a Warehouse conversion project that is now office space for a number of real estate, title, and architecture firms.

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A growing trend in urban centers is to convert existing warehouse space into open office area. In an effort to salvage historic sites, while minimizing renovation costs, this becomes a viable alternative.

However, many are now realizing that applying the same acoustic techniques to pre-existing structures will NOT get you the results you want. Warehouse space often has large, empty volumes, which causes unwanted echo. There are also thin partitions that, although once effective for physical separation, do little to combat unwanted noise.

Commercial Acoustics was contacted about this property in early 2016, and after a brief site visit, we bid on the project and began construction. We approached this full acoustic renovation in 3 steps, addressing each of the major issues:

  1. Soundproofing the floor where the footfall interrupted office interaction below
  2. Reduce echoes in both highbays, where speech intelligibility was greatly compromised due to excessive reverberation
  3. Soundproofing the wall between the two primary offices

Detailed Solution:

  1. Sound Blocking Floor

The floor above the office space was basic drywall subflooring, on 2×4 stud rafters. This mezzanine appeared to be constructed after the initial structure, and was hastily put together. As personnel walked over-head, the structure creaked and footfall was heavy and noisy. This situation often has 2 solutions; pull up the existing plywood and apply a GreenGlue or other acoustical decoupler, or apply another subfloor on the existing subfloor, which will increase the mass of the floor while also introducing a new decoupling layer. The customer opted for the latter. We installed our Floor Blokker material, and were able to increase the STC of the floor by over 10 points.

We were able to use this product despite the customer’s plan to later install tile, due to the Floor Blokker’s versatility – it may be installed decoupler-down for tile, while being installed decoupler-up for hard-wood flooring or carpeting. Installation took approximately 2 hours for a 400 square foot area.

Floor-Soundproofing-2

  1. Sound Absorbing in Echoey Room

The reverberation in this large space was due to several factors, in order of importance –

  • A large, voluminous room with no partitions or break-ups of any kind.
  • Plain, smooth walls and floors made of concrete, which has a very low NRC rating.
  • And finally, Parallel walls on each face of the room, which promotes standing waves.

To keep the cost down, we focused primary on our Echo Eraser material, which may be applied directly to the ceiling. While not as aesthetic as many acoustic panels, it is hidden among the joists of the roof, and remains out of sight out of mind (while keeping echoes out of the ear). With 22’ highbays, we rented a Genie lift and were able to install each highbay within 1 day.

While most of the Sabins, or sound absorption, was achieved via the Echo Absorber, we also neutralized local echoes with acoustic panels on the walls below. These are manufactured in-house in our Tampa facility, and installed in minutes.

Between the two solutions, we added over 1100 Sabins in acoustical absorption, at a relatively modest cost to the customer.

fausette-wall-2

  1. Sound Blocking Wall Between Offices

In an area where offices are separated by thin, old partitions, there’s no substitute for beefing up the existing wall. While open offices encourage spontaneous interaction and the corresponding teamwork, they also have the downside of unwanted noise.

The most challenging portion of this project was the wall between the two primary office areas. It was of flimsy, plywood construction, and had door thresholds already cut into it. These are notorious for leaking sound through the “path of least resistance”, and therefore, we plugged the door opening. We suggested removing the existing plywood, but due to budget and schedule constraints, the customer opted against this. We were able to apply our Wall Blokker product directly to the existing drywall, and then the well-known QuietRock over top of that. By stacking 2 decoupling and sound-blocking layers in succession, we were able to raise the STC of the wall from 40 to over 65. During the installation, we applied acoustical sealant to the edges where the wall intersected with the adjacent surface. This allows the wall to remain in a “floating” condition, and greatly minimizes the structure-borne noise transfer as well.

Review

The total cost of this soundproofing and acoustic project was under $20,000 and included site consultations, material selection and procurement, and installation over 6,000 sq ft of wall and flooring. The installation time was approximately 1 week, and the customer was able to bring in tenants at above-market value to recoup the capital costs due, in part, to the functional and stylish acoustically-treated space.

Soundproofing Home Music Studio

home studio

Commercial Acoustics provides expert soundproofing and acoustic advice and products for a variety of businesses. Here’s a look at an In-Home Studio that we helped design and build. For a step-by-step instruction on how to design and build your own home studio, read through our Home Music Studio tutorial.


Project Gallery:

See Our Client Demonstrate the Soundproofed Studio Control Room Above

Project Overview:

We were approached for this project in April 2016 to help a band develop an in-home studio with adequate sound-blocking and premium acoustics, with a mid-sized budget.

The studio was to be placed in a garage structure, just off the main house, making the vibrating structure-borne noise between the two units much less of an issue than typically seen in home music studios. When possible, we always suggest that clients use separate foundations for their primary abode versus that used for the music studio, and an effort to minimize this structure-borne noise.

The garage was relatively old, but the planks were in good condition, precluding the need to completely cover the exterior structure in sound-blocking materials. Our design included two primary areas – a larger recoding room, and smaller tracking room. The recording room would be used during the day, when noise ordinances are easier to abide by, while the inner control room would be reinforced so that high-amplitude music could be mixed and edited at any hour. Therefore, acoustic treatment was critical in the recording room to minimize unwanted reverberation, while sound-blocking was essential to the control room to prevent noise from disturbing neighbors late in the evening.

Our client built much of the framing himself, reducing labor costs on the project. Construction began in the two-car garage by first rolling out carpet cushioning, to prevent sound from transferring directly into the concrete floor. Floating floors were created using 4’ x 8’ shipping pallets topped with carpet padding sheets and plywood on top. The walls are standard framing with studs placed approximately 23.5″ apart for the purpose of fitting the 24″ wide (4″ thick) foam sheets (for absorption) in between each stud.

ted-bowne-layout

In the control room, plywood was selected for cost effectiveness, although heavy drywall is preferred where possible. We applied Wall Blokker Pro material between the studs and the plywood on the control room exterior. This same application may also be applied to the interior of the control room to further soundproof it. In this case, the control room was completely inside of the garage structure itself, a situation known as RWAR, or Room Within A Room. Due to this unique circumstance, we were able to minimize cost to the client by leaving the inner

Once all sound-blocking walls were constructed, we installed the foam between studs and on the ceilings, as well as thick carpeting on the ground. The inside walls were then covered in African wax print fabric to allow the sound to pass directly in to the foam for absorption.

The final result was a two-part in-home music studio, with separate recording and control room areas. The absorption quality in the recording room is extremely high, with a reverberation time of approximately 0.3 secs, which is essentially a “dead space”. The band is able to mix and edit music deep into the evenings due to the walls yielding an STC of approximately 65. Since installation, there have been no complaints from neighbors due to late-night noise.

Project Totals:

The total cost of the project was approximately $5,500, with most of it invested in the foam absorbing panels, then wood framing and Wall Blokker material. The framing and flooring took several days for the client to install, and the sound-blocking products took approximately 1 full day for 2 men.

Although Home Studios may range in price from $2,000 all the way to hundreds of thousands, Commercial Acoustics aims at offering our clients a range of options to best meet their needs and fit their budget. Call us today for a free consultation on your project.

 

Step-By-Step Buildout of the Soundproofed Home Studio [Slideshow]


Learn More About How You can Soundproof Your Home Studio today – Get a Free Quote from our Soundproofing Experts or use our Product Selector Tool to choose the perfect soundproofing products for your home studio.