Sound transmission loss of gypsum wallboard partitions. Report #3. 2 × 4 in. wood stud partitions

Using the data bank of the acoustics laboratory of Domtar Research, statistical equations based on surface density are derived for predicting the sound transmission class and sound transmission loss of double leaf wall partitions. The partitions are constructed using gypsum wallboard and 2×4 in. wood studs with or without glass fiber batts (R‐7) in the cavity spaces. The results predicted using these equations are found to be in good agreement with results on similar assemblies tested at other laboratories. The equations are then used to illustrate the effects of surface density and method of board attachment on sound transmission loss. The STC of wood stud partitions is shown to be reduced significantly if screws directly into the studs are used for the attachment of a second layer of wallboard. The effectiveness of a glass fiber batt (R‐7) cavity filler in improving STC is also shown to be highly dependent upon the method of second layer attachment. Several methods of increasing the sound transmission loss of wood stud partitions are compared.