Part J4 Building fabric

(1) The Deemed-to-Satisfy Provisions of this Part apply to building elements forming the envelope of a Class 3 and Class 5 to 9 building.

(2) NSW J4D3, applies to building elements forming the envelope of a sole-occupancy unit in a Class 2 building and a Class 4 part of a building.

(3) (2) only applies to thermal insulation in a sole-occupancy unit in a Class 2 building and a Class 4 part of a building where a development consent specifies that the insulation is to be provided as part of the development.

(1) Where required, insulation must comply with AS/NZS 4859.1 and be installed so that it—

1. abuts or overlaps adjoining insulation other than at supporting members such as studs, noggings, joists, furring channels and the like where the insulation must be against the member; and
2. forms a continuous barrier with ceilings, walls, bulkheads, floors or the like that inherently contribute to the thermal barrier; and
3. does not affect the safe or effective operation of a service or fitting.

(2) Where required, reflective insulation must be installed with—

1. the necessary airspace to achieve the required R-Value between a reflective side of the reflective insulation and a building lining or cladding; and
2. the reflective insulation closely fitted against any penetration, door or window opening; and
3. the reflective insulation adequately supported by framing members; and
4. each adjoining sheet of roll membrane being—
   1. overlapped not less than 50 mm; or
   2. taped together.

(3) Where required, bulk insulation must be installed so that—

1. it maintains its position and thickness, other than where it is compressed between cladding and supporting members, water pipes, electrical cabling or the like; and
2. in a ceiling, where there is no bulk insulation or reflective insulation in the wall beneath, it overlaps the wall by not less than 50 mm.

(4) Roof, ceiling, wall and floor materials, and associated surfaces are deemed to have the thermal properties listed in Specification 36.

(5) The required Total R-Value and Total System U-Value, including allowance for thermal bridging, must be—

1. calculated in accordance with AS/NZS 4859.2 for a roof or floor; or
2. determined in accordance with Specification 37 for wall-glazing construction; or
3. determined in accordance with Specification 39 or Section 3.5 of CIBSE Guide A for soil or sub-floor spaces.

(1) The Total System U-Value of wall-glazing construction, including wall-glazing construction which wholly or partly forms the envelope internally, must not be greater than—

1. for a Class 5, 6, 7, 8 or 9b building or a Class 9a building other than a ward area, U2.0; and
2. for a Class 3 or 9c building or a Class 9a ward area—
   1. in climate zones 1, 3, 4, 6 or 7, U1.1; or
   2. in climate zones 2 or 5, U2.0; or
   3. in climate zone 8, U0.9.

(2) The Total System U-Value of display glazing must not be greater than U5.8.

(3) The Total System U-Value of wall-glazing construction must be calculated in accordance with Specification 37.

(4) Wall components of a wall-glazing construction must achieve a minimum Total R-Value of—

1. where the wall is less than 80% of the area of the wall-glazing construction, R1.0; or
2. where the wall is 80% or more of the area of the wall-glazing construction, the value specified in NSW Table J4D6a.

(5) The solar admittance of externally facing wall-glazing construction, excluding wall-glazing construction which is wholly internal, must not be greater than—

1. for a Class 5, 6, 7, 8 or 9b building or a Class 9a building other than a ward area, the values specified in NSW Table J4D6b; and
2. for a Class 3 or 9c building or a Class 9a ward area, the values specified in NSW Table J4D6c.

(6) The solar admittance of a wall-glazing construction must be calculated in accordance with Specification 37.

(7) The Total system SHGC of display glazing must not be greater than 0.81 divided by the applicable shading factor specified in S37C7.