While at a get-together at a friend’s house, a small group of us were talking in the great room, just outside the guest bathroom. A friend needed to use the bathroom. Our conversation was interrupted by a sudden surprise sprinkle sound—and I’m not so sure it was the faucet. And no, the exhaust fan they depended on could not drown out the sound. When the friend came out, I felt embarrassed for them, for they had no clue it was so audible. Later, I tapped on the door and, as suspected, it was a hollow core door. This is a shame, especially since the house was a luxury home.
I live in a house where the sound from the TV in our family room can be heard through the wall in our master bedroom, even at a modest volume. Sounds easily migrate through metal stud walls and hollow core doors. Normal conversations and sounds can be heard through them; they just simply do not provide enough buffering for sound privacy.
“When it comes to privacy, every dime you spend is worth a dollar.”
Amanda Bowers, The Kearney Companies
Walls and Doors serve three primary purposes: security, visual privacy, and sound privacy. The third purpose is just as important as the first two, yet is often overlooked, or simply ignored for the sake of a cheaper door selection or construction materials.
Home design and building professionals should consider specifying acoustical walls and doors for sound sensitive rooms, with doors and construction materials achieving high STC (Sound Transmission Class) ratings.
Control sound and offer more value in new home construction or remodels, using the following construction guidelines:
- On a floor plan, use a highlighter marker to identify rooms or areas that require sound privacy or buffering, and highlight the doors and walls surrounding all bedrooms, bathrooms (especially toilet closets) and air conditioning/heater closets or any other room that requires isolation from noise. Include a solid core door with a threshold; doors should not be undercut for venting. Therma-Tru noise reduction doors is one brand that provides an acceptable STC rating of 36;
- Use wood studs for all interior walls, not metal studs;
- For best acoustic management, finish walls using National Gypsum Gold Bond® brand 1/2″ SoundBreak® XP® Gypsum Board with Sporgard™ or CertainTeed’s SilentFX Noise-Reducing Gypsum Board or similar specialty wallboard. These high-density gypsum core boards consist of a layer of viscoelastic damping polymer sandwiched between two pieces of high density mold resistant gypsum board, providing constrained layer damping;
- Also fill the wall cavities with Certainteed NoiseReducer Sound Attenuation Batt Insulation, Owens Corning Sound Attenuation Batts (SAB’s) or mineral wool batts. These provide excellent in-place acoustic performance for interior partition acoustic systems. Depending on the construction method used, SABs can improve Sound Transmission Class (STC) ratings by 4 to 10 dBs.
- One alternative to the specialty drywall is to use Acoustiblock’s soundproofing membrane attached directly to the wood stud framing, before wallboard is applied. The pliable, 3mm (1/8″) thick Acoustiblok membrane is engineered not to stop or even absorb sound, but through a unique thermodynamic process that reduces sound transmission virtually the same as 24-inches of concrete. A typical 2 x 4 gypsum stud wall is usually 33 to 35 STC. Acoustiblok installed in the 2 x 4 wall is lab certified at an STC of 52, better than 12″ of poured concrete (STC 51).