Insufficient Sealing of Partition
Once the wall assembly is built, all direct pathways for sound transmission need to be blocked. Drywall installers should thoroughly seal any penetrations, such as electrical outlets, switch boxes, or telephone boxes. These penetrations should also be staggered from similar openings on the opposite side of the wall. Avoid having more than one penetration in a stud bay whenever possible. To avoid flanking—which is when sound travels through gaps located at the perimeter of the wall assembly and its corners—drywall installers should seal the perimeter with caulk after everything else is tightened up.
In recent years, we’ve seen several new acoustical gypsum board and insulation products enter the marketplace promising to create wall assemblies with optimal acoustical performance. These new products and technologies, however, are significantly more expensive than a traditional wall assembly with resilient channels, sound-absorbing insulation, and acoustical sealant. At a time when clients are more budget-conscious, this may be an important thing to consider.
Contractors who follow the guidelines that we’ve outlined here and install resilient channels properly can provide their clients a high-STC wall assembly at a fraction of the price of those made with alternative materials.
Michael Kerner is code-development manager at ClarkDietrich Building Systems in West Chester, Ohio.