Part 10.7 Sound insulation

(1) A separating wall between Class 1 buildings, or a wall that separates a Class 1 building from a Class 10a building which is not associated with the Class 1 building must—

1. have an R_w + C_tr (airborne) not less than 50; and
2. be of discontinuous construction if it separates a bathroom, sanitary compartment, laundry or kitchen in one Class 1 building from a habitable room (other than a kitchen) in an adjoining Class 1 building (see Figure 10.7.1).

(2) A wall required to have sound insulation must continue to—

1. the underside of the roof above; or
2. a ceiling that provides the sound insulation required for the wall.

The Rw + Ctr sound insulation rating required by 10.7.1(1)(a) must—

1. be determined in accordance with AS/NZS ISO 717.1, using results from laboratory measurements; or
2. comply with 10.7.5 to 10.7.8 and the relevant provisions of 10.7.3.

To achieve the appropriate level of sound insulation, walls must be constructed as follows:

1. Stud wall junction — junctions of sound insulated walls with any perimeter walls and roof cladding must be sealed in accordance with Figure 10.7.3a.
2. Masonry — units must be laid with all joints filled solid, except for articulation joints complying with 5.6.8, including those between the masonry and any adjoining construction.
3. Concrete panels — must have joints between panels and any adjoining construction filled solid.
4. Plasterboard sheeting —
   1. If two layers are required, the second layer joints must not coincide with those of the first layer (see Figure 10.7.3b).
   2. Joints between sheets including the outer layer or between sheets and any adjoining construction must be taped and filled solid.
5. Steel framed construction — steel framing and perimeter members must be installed as follows:
   1. Steel framing members must be not less than 0.6 mm thick.
   2. Studs must be not less than 63 mm in depth unless another depth is specified in 10.7.5 to 10.7.8.
   3. All steel members at the perimeter of the wall must be securely fixed to the adjoining structure and the joints must be caulked so that there are no voids between the steel members and the wall.
6. Timber-framed construction — timber studs and perimeter members must be installed as follows:
   1. Noggings and like members must not bridge between studs supporting different wall leaves.
   2. All timber members at the perimeter of the wall must be securely fixed to the adjoining structure and the joints must be caulked so there are no voids between the timber members and the wall.

(1) Services must not be chased into concrete or masonry separating walls.

(2) If a duct, soil, waste, water supply or stormwater pipe is located in a separating wall—

1. a door or panel providing access to a duct or pipe required to be separated must—
   1. not open into any habitable room, other than a kitchen; and
   2. in any other part must be firmly fixed so as to overlap the frame or rebate of the frame by not less than 10 mm and be constructed of—
      1. wood, plasterboard or blockboard not less than 33 mm thick; or
      2. compressed fibre reinforced cement sheeting not less than 9 mm thick; or
      3. other suitable material with a mass per unit area not less than 24.4 kg/m²; and
2. in the case of a water supply pipe, it must—
   1. only be installed in discontinuous construction; and
   2. in the case of a water supply pipe that serves one dwelling, not be fixed to the wall leaf on the side of any other dwelling and have a clearance not less than 10 mm to the other wall leaf.

(3) Electrical outlets must be offset from each other—

1. in masonry walling, not less than 100 mm; and
2. in timber or steel-framed walling, not less than 300 mm.

(1) Acceptable forms of construction for masonry walls are set out in (2) to (6).

(2) Two leaves of 110 mm clay brick masonry with—

1. a cavity not less than 50 mm between leaves; and
2. 50 mm thick glass wool insulation with a density of 11 kg/m³ or 50 mm thick polyester insulation with a density of 20 kg/m³ in the cavity,

has an R_w + C_tr of not less than 50, if constructed in accordance with Figure 10.7.5a.

(3) Two leaves of 110 mm clay brick masonry with—

1. a cavity not less than 50 mm between leaves; and
2. 13 mm cement render on each outside face,

has an R_w + C_tr of not less than 50, if constructed in accordance with Figure 10.7.5b.

(4) A single leaf of 110 mm clay brick masonry with—

1. a row of 70 mm x 35 mm timber studs or 64 mm steel studs at 600 mm centres, spaced 20 mm from the masonry wall; and
2. 50 mm thick mineral insulation or glass wool insulation with a density of 11 kg/m³ positioned between studs; and
3. one layer of 13 mm plasterboard fixed to outside face of studs and outside face of masonry,

has an R_w + C_tr of not less than 50, if constructed in accordance with Figure 10.7.5c.

(5) A single leaf of 90 mm clay brick masonry with—

1. a row of 70 mm x 35 mm timber studs or 64 mm steels studs at 600 mm centres, spaced 20 mm from each face of the masonry wall; and
2. 50 mm thick mineral insulation or glass wool insulation with a density of 11 kg/m³ positioned between studs in each row; and
3. one layer of 13 mm plasterboard fixed to studs on each outside face,

has an R_w + C_tr of not less than 50, if constructed in accordance with Figure 10.7.5d.

(6) A single leaf of 220 mm brick masonry with 13 mm cement render on each face has an R_w + C_tr of not less than 50, if constructed in accordance with Figure 10.7.5e.

(1) Acceptable forms of construction for concrete walls are set out in (2) to (5).

(2) 150 mm thick plain off form concrete, has an R_w + C_tr of not less than 50, if constructed in accordance with Figure 10.7.6a.

(3) 200 mm thick concrete panel with one layer of 13 mm plasterboard or 13 mm cement render on each face, has an R_w + C_tr of not less than 50, if constructed in accordance with Figure 10.7.6b.

(4) A 100 mm thick concrete panel with—

1. a row of 64 mm steel studs at 600 mm centres, spaced 25 mm from the concrete panel; and
2. 80 mm thick polyester insulation or 50 mm thick glass wool insulation with a density of 11 kg/m³, positioned between studs; and
3. two layers of 13 mm plasterboard fixed to the outside face of studs and one layer of 13 mm plasterboard fixed to the outside face of the concrete panel,

has an R_w + C_tr of not less than 50, if constructed in accordance with Figure 10.7.6c.

(5) A 125 mm thick concrete panel with—

1. a row of 64 mm steel studs at 600 mm centres, spaced 20 mm from the concrete panel; and
2. 70 mm polyester insulation with a density of 9 kg/m³, positioned between studs; and
3. one layer of 13 mm plasterboard fixed to the outside face of the studs,

has an R_w + C_tr of not less than 50, if constructed in accordance with Figure 10.7.6d.

(1) Acceptable forms of construction for autoclaved aerated concrete walls are set out in (2) to (4).

(2) A 75 mm thick autoclaved aerated concrete wall panel with—

1. a row of 64 mm steel studs at 600 mm centres, spaced 20 mm from the autoclaved aerated concrete wall panel; and
2. 75 mm thick glass wool insulation with a density of 11 kg/m³ positioned between studs; and
3. one layer of 10 mm moisture resistant plasterboard or 13 mm fire protective grade plasterboard fixed to outside face of studs and outside face of autoclaved aerated concrete wall panel,

has an R_w + C_tr of not less than 50, if constructed in accordance with Figure 10.7.7a.

(3) A 75 mm thick autoclaved aerated concrete wall panel with—

1. a row of 64 mm steel studs at 600 mm centres, spaced 35 mm from the autoclaved aerated concrete panel wall; and
2. 28 mm metal furring channels fixed to the outside face of the autoclaved aerated concrete wall panel, with 50 mm thick polyester insulation with a density of 9 kg/m³ positioned between furring channels and one layer of 13 mm fire protective grade plasterboard fixed to furring channels; and
3. 105 mm thick glass wool insulation with a density of 7 kg/m³ positioned between studs; and
4. one layer of 13 mm fire protective grade plasterboard fixed to the outside face of the studs,

has an R_w + C_tr of not less than 50, if constructed in accordance with Figure 10.7.7b.

(4) Two leaves of 75 mm autoclaved aerated concrete wall panel with—

1. a cavity not less than 30 mm between panels containing 50 mm glass wool insulation with a density of 11 kg/m³; and
2. one layer of 10 mm plasterboard fixed to outside face of each panel,

has an R_w + C_tr of not less than 50, if constructed in accordance with Figure 10.7.7c.

(1) Acceptable forms of construction for timber and steel framed walls are set out in (2) and (3).

(2) Two rows of 90 mm x 35 mm timber studs or two rows of 64 mm steels studs at 600 mm centres with—

1. an air gap not less than 20 mm between the rows of studs; and
2. 50 mm thick glass wool insulation or 60 mm thick polyester insulation with a density of 11 kg/m³, positioned between one row of studs, and
3. two layers of 13 mm fire protective grade plasterboard or one layer of 6 mm fibre cement sheet and one layer of 13 mm fire protective grade plasterboard, fixed to outside face of studs,

has an R_w + C_tr of not less than 50, if constructed in accordance with Figure 10.7.8a.

(3) Two rows of 64 mm steel studs at 600 mm centres with—

1. an air gap not less than 80 mm between the rows of studs; and
2. 200 mm thick polyester insulation with a density of 14 kg/m³ positioned between studs; and
3. one layer of 13 mm fire-protective grade plasterboard and one layer 13 mm plasterboard on one outside face and one layer of 13 mm fire-protective grade plasterboard on the other outside face,

has an R_w + C_tr of not less than 50, if constructed in accordance with Figure 10.7.8b.