Sound Control and Urban Infill

Any builder or architect who works on residential projects in major urban areas knows that there is strategy of building in high-density neighborhoods. In many cities, multifamily construction is popping up around every corner, and single-family homes are being built closer and closer together.

Sound control is a key concern for both building industry professionals and residents in these areas of urban infill. The International Building Code (IBC) and International Residential Code (IRC) require certain sound transmission class (STC) ratings on walls and floor/ceiling separations depending on the construction type. STC ratings can range anywhere from 15 to 55+.

An STC rating of 50 is required on wall assemblies specified for separations between living spaces, between living spaces and certain public areas and corridors, and within multifamily structures. An STC rating of 50 is considered "very good" and indicates that loud speech is faintly heard and normal speech is usually inaudible. Although 50 is the minimum, builders and architects are seeking out products that perform above and beyond the IBC/IRC STC requirement.

LP^® FlameBlock^® Fire-Rated OSB Sheathing is a code-compliant component of the U350-B wall assembly for 2-hour fire-rated partition walls commonly used in multifamily construction and townhomes. Recent product testing conducted by LP Building Products and Intertek, a product testing and certification company, showed that the U350-B assembly well-exceeded the code minimum with a STC rating of 62. Not only does this wall assembly carry an impressive STC rating, it also provides greater design flexibility compared to the traditional partition wall assembly using shaft wall liner. In the U350-B assembly, the two-sided layer of LP FlameBlock sheathing eliminates the heavy, 1-inch-thick gypsum and associated hardware, resulting in labor and material cost savings plus a reduction in dead load.

As structures continue to be built closer together, the demand for better sound transmission control is bound to be a major factor for architects, builders, renters and homeowners. When choosing the best building products, it's important to look at the performance of the entire assembly-STC rating, code compliancy and building efficiency.