STC Ratings

When you’re designing or building a home, you need to think about every detail. This includes STC ratings. Let’s take a look at what ratings mean and how they impact construction of a home.

STC is an abbreviation for Sound Transmission Class. Introduced in the 1960s, STC ratings are a system of comparing various standards of walls, ceilings, windows and doors for how they lessen sound transference between rooms.

Architects and construction professionals rely on STC ratings to decide which construction materials to use for a project. The higher the STC rating, the better the material is at blocking sound at common frequencies. Ratings range from 25-60+.

In multi-family construction, a STC rating of 25 means that a normal conversation can be heard through the wall by neighbors. At 30, a loud conversation is audible and understood. At 35, loud speech is noticeable, but others can’t make out what is being said. At 45, loud speech is detectable, but not audible. Loud sounds fade to barely discernable at a 50, while 60+ is considered solid soundproofing with no disturbances to neighbors.

A typical home has walls with a STC rating of 33, although in areas like home theaters and offices where disturbances are unacceptable, a STC rating from 50-80 is required.

However, keep in mind that it’s tricky to define low frequency sounds. You can have a higher STC rating, but the wall still may not work for your application. You can choose soundproofing materials that will work best or if you are retrofitting a home, you can use a decibel meter to test the walls.

Understanding STC ratings, you can better determine the level of protection your project needs. Call us now for your sound proofing and acoustics requirements.