Sound attenuation provided by several wood-framed floor-ceiling assemblies with troweled floor toppings

Abstract

The sound attenuation provided by 11 wood-framed floor-ceiling assemblies with troweled floor toppings is presented. Three tests of assemblies with nailed gypsum board ceilings provided sound transmission class (STC) values of 48 to 50. By comparison, seven assemblies with ceilings applied on resilient channels and one with a suspended ceiling gave STC values of 55 to 59. The addition of glass fiber in the joist space, or the substitution of factory-fabricated, plywood-web joists for solid wood joists, provided less impressive improvements in STC values. Tests of three assemblies with vinyl tile floor covering and with pad and carpet provided an impact sound insulation class (IIC) of 50 to 52 with tile and 72 to 77 with carpet. The improvements in IIC that were anticipated from other changes in the floor-ceiling assemblies were clouded by the measuring and rating system. The need for a method other than the current ISO/R140 international standard for realistically measuring and rating resistance to impact sound transmission is emphasized by results of these tests.