In general, it is important to limit noise and sound transmission through walls. While important in residential structures, this is especially critical in certain commercial structures such as hospitals, movie theaters, concert halls,hotels and airports that require substantial noise reduction. Homes built on noisy streets or near interstate highways will benefit from reduced sound transmission. Lastly, many builders are using BuildBlock ICFs for sound proofing in interior rooms such as a home theaters and media rooms.
Insulating Concrete Forms, (ICFs) can be used to construct nearly any type of building, and offer a wealth of benefits to the builder and the buyer. ICFs offer a substantial reduction in sound transmission, and can quiet the noisiest environments. BuildBlock ICFs with 5/8” drywall on both sides, can exhibit an Sound Transmission Class (or STC) rating of 54. This is a dramatic reduction in sound penetrating from the outside.
The list below describes the sound abatement capacities of various STC ratings. These values, like R-values can vary due to the number of openings and the efficiency of windows and doors at mitigating sound transmission.The STC rating of a wall assembly refers to its resistance to sound transmission. Sound is measured in decibels, (db) and is on a logarithmic scale, meaning that the values are not linear in nature, and a 50db sound is not twice as loud as a 25db sound. A doubling of volume would correspond approximately to a 10db change.
Sound Transmittance Class Description
|STC Rating||Privacy Afforded|
|25||Normal speech is easily understood.|
|30||Normal speech is heard, but not understood.|
|35||Loud speech is heard and somewhat understood.|
|40||Loud speech heard, but not understood.|
|45||Loud speech barely heard.|
|50||Shouting barely heard.|
|55||Shouting not heard.|
|Sound mitigation can be improved by adding mass, increasing or adding air space and adding absorptive material such as insulation.
Source: Table 7, Costs and Benefits of Insulating Concrete Forms for Residential Construction, U.S. Department of Housing and Urban Development, Washington, DC, December 2001.