Acoustics Expertise

Impact sound is caused by contact with a barrier and is measured with an IIC (Impact Insulation Class) rating. Flooring has the largest effect on impact sound as opposed to in-room sound and airborne sound. Impact sound is a major concern in multifamily communities.

To measure impact sound, a standardized machine taps on the floor repetitively with metal hammers. A receiving device is placed in the room below to measure the sound in decibels and across a range of frequencies. The resulting score is the Impact Insulation Class rating, or IIC.

IIC ratings can range from as low as 25 up to 110. The higher the score, the more impact sound is reduced. The International Building Code requires a minimum IIC of 50, however, most people can still hear sounds through a barrier until we reach a score of 65.

Choosing the correct flooring construction and products can have a major influence on sound in multifamily communities. Considering acoustics from the beginning of a project can save time and money.
Learn about real situations in multifamily communities and what it cost to mitigate impact sound after initial construction.