Reducing Exterior Noise
NOTE: We do not sell windows or have any connection to companies that do. We simply are advising on how to best deal with exterior windows and what options you have for your project.
How to reduce noise from outside is an exceedingly common noise issue, especially for those living in high population areas. Several products and wall assemblies will help with exterior noise reduction. However, without addressing the weakest points, the wall will be one expensive, and still pretty noisy, exterior assembly.
A typical exterior wall consists of a layer of drywall, 2×4 framing, R-13 insulation, a layer of OSB sheathing, and either siding, stucco, or brick with the occasional window or door. The STC rating of your exterior wall will vary somewhere between STC 35 to 45 depending on the exterior finish with an OITC rating of approximately 35.
DEAL WITH THE WEAKEST LINKS
The size of the door or window in relation to the size of the wall is important. A door or window that takes up most of the wall is more of an issue than a door or window that takes up 10% of the wall surface. Either way, if your exterior wall has a door or window, then it needs to be addressed. Doors and windows are typically in the STC 20-30 range, much too low when compared to the average exterior wall.
If your wall has both a window and a door, then the window should be treated first since it is likely the weakest of the two (usually 10 STC points less than a door). Replacing your windows with ’soundproof’ windows will help performance. To replace an exterior window, first remove the perimeter of the window frame. If the exterior is rock, brick, or stucco, then replacing the window could turn into a significant project. Replacing your windows with a high STC rated window will provide the cleanest look, as well as pretty good results from a single window. We recommend Quiet Line windows from Milgard.
However, this construction headache can be avoided by adding a second window to the inside of your window frame. The STC rating of the opening improves to at least the mid 40’s STC with the addition of the second double pane laminated window. A dramatic improvement achieved with minimal construction. Increase this overall rating by increasing the mass of the glass used. For maximum performance (in line with online soundproof window vendors), add a 3/8" laminated glass combined with a 5/8" laminated glass in an insulated glass unit. This makes for a very heavy window that will isolate up to 60 STC.
Following any of the above should put your window's rating higher than your wall rating. Now you have the wall to deal with!
Watch the video below to see the effect of adding a second window to your window installation.
FINISH THE WALL
As mentioned before, an exterior wall STC rating is likely somewhere in the mid 30’s to mid 40’s. With minimal demolition, the most basic way to soundproof exterior walls is by adding a layer of 5/8″ drywall with Green Glue Compound in between the layers or by adding 1 LB or 2 LB mass loaded vinyl (MLV) over the existing drywall and covering that with a new layer of drywall. The Compound with an additional layer of drywall will bring the STC rating up to the low to mid 50’s if the wall is 24" on center framing. The MLV will bring the wall rating into the mid-40's or higher, regardless of the stud spacing. Without major investment into the project, this is likely as good as it will get. View Green Glue Compound tubes or Green Glue Compound pails or TotalMass MLV.
To us, the best bang for the buck is a second window added to the existing window frame with Green Glue Compound or MLV and an additional layer of drywall added to the existing drywall. If your wall does not have any windows or doors installed, consider upgrading your wall using either a double stud framing technique or resilient sound clips like the GenieClip® RST or HushFrame Rafts. The added performance of the GenieClips® RST or HushFrame Raft over Green Glue Compound and TotalMass MLV in a wall without windows or doors is immense for all frequencies.