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Frequently Asked Questions
Cement & Concrete
Technology Home > FAQs> STC
Q: What are the Sound Transmission Class (STC) ratings for concrete and
masonry walls?
A: The actual Sound Transmission
Class (STC) for your wall will depend on the type of wall, the finish,
and the weight of the wall per square foot of surface area. STC
ratings for partition materials may range from 40 to more than 60
with higher values providing less sound transmission. The Federal
Housing Administration (FHA) requires a minimum STC of 46 to limit
sound transmission from unit to unit in multi-family dwellings.
See the table below for details. For example, a 4
in. masonry wall at 18 lb/ft2 would be rated at 40, while
the same thickness of wall with a weight of 27 lb/ft2
would have a rating of 45. An example of a painted wall (both sides)
weighing 22 lb/ft2 is rated at 43.
Source: IS159
PCA offers the following resources on acoustic properties of concrete
and masonry for a variety of wall and floor assemblies:
1) Acoustics of
Concrete in Buildings, IS159
2) Sound Transmission
Loss Through Concrete and Masonry Walls, RD066
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