Sound insulation performance is based on the overall construction, e.g. partition or floor, and not just the individual plasterboards that only form part of these constructions.
If we take a GypWall metal stud partition as an example of a construction, in addition to the plasterboard lining itself the system will also consist of metal studs, head and base channels and screw fixings. Since it is not possible to build a plasterboard partition without a supporting framework all of these components are vital to the overall acoustic performance of the partition, therefore the plasterboard cannot be considered on its own in terms of sound insulation.
Looking through the various GypWall partition sections of the White Book you will see that different combinations of plasterboards and studs will provide different levels of sound insulation.
For example if we consider the GypWall Classic system:
- Single layer 12.5mm Gyproc WallBoard each side of Gypframe 48 S 50 studs provides Rw 34dB
- Single layer 12.5mm Gyproc SoundBloc each side of Gypframe 48 S 50 studs provides Rw 37dB
- Double layer 12.5mm Gyproc WallBoard each side of Gypframe 48 S 50 studs provides Rw 42dB
- Double layer 12.5mm Gyproc SoundBloc each side of Gypframe 48 S 50 studs provides Rw 46dB
As you can see by varying the type of board and number of layers the different levels of Sound Reduction Index (Rw) that may be required by the project can be met. This single figure rating method is used for laboratory airborne sound insulation tests. The figure indicates the amount of sound energy being stopped by the separating building element (the higher the figure the better in terms of performance). Various factors will contribute to the overall sound insulation performance of a partition system, such as:
- Board type, thickness and number of layers
- Size of partition cavity
- Stud type, width and gauge
- Stud centres
- Insulation type, thickness and density
- Staggered board joints
- Screw fixing type, length and fixing centres
- Jointing / plastering
- Gap sealing
- Fixing details at the partition head and base
- Addition of components such as resilient bars
Similar factors also exist for ceiling membranes and floor elements, therefore when considering any of our systems in terms of Sound Insulation reference should be made to the system performance tables for that type of construction in our White Book. Each section of the White Book organises our systems according to the sound insulation (Rw values) and provides all of the vital construction and specification information for meeting that performance (such as stud type, centres, etc).
Further information about acoustic performance can be found in WHITE BOOK Chapter 02 Section 01 Page 08.