Timber-frame party wall construction
Sound insulation is a factor that must be considered during the construction of timber frame party walls. There are a number of items that can be adhered to achieve an acceptable level of sound insulation:
Mineral fiber sound insulation with a minimum design density of 12 kg/m^3^ should be used; correct fitting procedures should be followed as per the manufacturer’s instructions to avoid the insulation from sagging creating gaps.
A cavity of 40 mm minimum must be left between the party walls. This gap provides structural isolation and helps reduce noise transfer.
Using two layers of plasterboard can create a dense wall lining; typically, a minimum thickness of 30 mm is accepted. This 30mm thickness is achieved by using one layer of 19 mm plank type plasterboard mounted horizontally that is then overlaid by a layer of 12 mm plasterboard mounted vertically (joints must be staggered).
Attic spaces
Whether the attic space is classed as habitable space or non-habitable space determines if the insulation must be continued to roof level in the party wall (habitable space requires sound insulation to the roof level). The same provision is made based on whether the minimum thickness of 30 mm of plasterboard is carried up to the roof level or if two layers of 12 mm plasterboard are acceptable.
It is of the upmost importance that the correct installation procedures are adhered to on-site to ensure continuity of insulation is maintained around all opes and joints in the party wall; especially ensuring no gaps are present for sound to travel through.
