Soundproofing is becoming more of a major concern as families become larger and as more activities that were once confined to outside the home are now brought inside the home. These outside activities namely are the introduction of home offices, media rooms with full-sized projection rooms, video game rooms, and more.
Slow The Vibration
Since sound is created by the transmission of vibrations through the air the logical thing to do is to slow down those vibrations.
So one rule of thumb is to think in terms of airflow into your house and how that airflow gets in. The mindset you use when finding cold drafts in your house is the same you use when looking for “sound drafts.”
It may seem improbable, but sealing gaps and cracks in walls, doors, windows is one way of soundproofing your house. Adding weatherstripping to the bottoms of doors, caulking cracks, and putting up storm doors and windows reduces the airflow that brings these “sound drafts.”
Measuring Sound Transmission
One method of measuring sound transmission is STC, or Sound Transmission Class. Higher STC numbers mean better soundproofing. For instance, an STC of 50 means that you will not hear a person talking loudly on the other side of a wall.
As you might imagine, sealing “sound drafts” is great, but you need more than that. The simplest way is to sandwich another layer of 5/8” drywall on top of your existing wall.
In terms of hanging the drywall, it’s a fairly simple process. But where you’ll encounter difficulties is in extending electrical outlets, phone jacks, baseboards, door and window trim. You need to extend these items so that they will be flush with the new wall surface.
So your average wall faced with 1/2” drywall has an STC of 30.
Sandwiching one additional layer of 5/8” drywall on one side brings the STC up to 38. Doing this on both sides brings the STC up to 40.