How to Soundproof a Room From Outside Noise
To soundproof a room from outside noise, fix the windows first. Most standard double-pane windows rate around STC 26, per Pella, against STC 36 for an insulated wood stud wall with one layer of 5/8 inch Type X drywall per side in Table 9.10.3.1.-A of the BC Building Code. Then seal the outside door and vents. The exterior wall goes last.
Windows: seal, insert, then replace
An interior insert gives the biggest single gain. In tests at the British Columbia Institute of Technology reported by Indow, double-pane windows with inserts reached STC 42 to 45, an average 14 dB better from 125 Hz to 4 kHz.
| Window | STC |
|---|---|
| Standard double pane, two 3 mm panes (Pella) | About 26 |
| Typical dual pane (Andersen) | 25 to 30 |
| Insulated wood stud wall, 1 layer of drywall per side (BC table) | 36 |
| Double pane plus an interior insert | 42 to 45 |
- Seal the frame. NRC Canada's Building Digest 240 says a window with good weatherstripping usually rates 3 to 5 STC lower than the same window sealed shut. Caulk frame gaps and replace worn weatherstripping.
- Add an insert. Indow lists its inserts from $44 per square foot MSRP, $528 for a 3 by 4 foot window, at the time of writing.
- Replace the glass last. Andersen recommends laminated glass or panes of mismatched thickness for sound.
Then the door, vents, and exterior wall
Next, the outside door. TruStile's 1-3/4 inch MDF door rates STC 21 with basic seals and 33 with a full seal package. Vents and mail slots leak: Zero International notes that "sound travels through any opening with very little loss."
The wall waits because glass is the weak point. In a BCIT study of six wood frame houses, whole facades measured STC 26 to 35, and the one with the most glazing (46 percent) scored lowest. With the openings sealed, resilient channel and new drywall on the inside face lift that insulated, one layer per side stud wall from STC 36 to 45 in the BC table. The build is in how to soundproof a room.
The full studio plan is in how to soundproof a home studio.
Related questions
Do triple pane windows block more outside noise?
Not reliably. NRC Canada found triple glazing usually rates about the same STC as double glazing. Laminated glass, mismatched pane thicknesses, or a wide air gap do more.
What rating should I check for traffic noise?
OITC, the Outdoor-Indoor Transmission Class, which Andersen describes as the measure for traffic, airplane, and construction noise. Higher is better, as with STC.
Can renters block outside noise?
Yes, mostly. Indow's inserts press into the frame on a compression tube, though larger ones need small frame brackets screwed in, so check with your landlord. More options are in how to soundproof a room in an apartment.
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