Sound leaks, like water leaks, must be prevented because sound will travel through any size opening with little loss. As any homeowner knows, even the most expensive roofing system will leak when it is raining if there is only one tiny hole in it! For sound, the more effective a solid construction is as a sound isolator, the more serious the sound leak. For example, a 1-in ² hole in a 100-ft ² gypsum board partition can transmit as much sound energy as the rest of the partition, thereby destroying its sound-isolating effectiveness.

Consequently, when sound isolation is required, always seal cracks and open joints in partitions, avoid back-to-back electrical outlets, and eliminate all other potential sound leaks. The example partition shown at the left on the facing page has sound leaks along both the head and floor tracks. By caulking the perimeter of the gypsum board base layer on both sides, the TL can be increased by more than 20 dB.