Part 5.6 Masonry components and accessories

(1) Part 5.6 is subject to the limitations set out in H1D5(6)(c)(i), (ii) and (iii).

(2) Part 5.6 need not be complied with if H1D5(6)(a) or (b) are complied with.

(1) Masonry veneer masonry units must have a minimum compressive strength of—

1. 3 MPa for solid or cored units; or
2. 10 MPa for hollow units.

(2) Cavity masonry and single skin masonry units must have a minimum compressive strength of—

1. 5 MPa for solid or cored units; or
2. 10 MPa for hollow units.

(3) Masonry cavity walls must have a minimum leaf thickness of 90 mm.

(4) Subject to (5), masonry units must be—

1. either clay or calcium silicate brick or concrete brick or block; and
2. classified and used in the exposure conditions appropriate to their classification as described in (6).

(5) Mixing of panels consisting of clay masonry units with panels consisting of concrete or calcium silicate masonry units is not permitted unless—

1. at vertical junctions, a control joint is installed; and
2. at horizontal junctions between panels of different materials, a slip joint using a membrane similar to that used for damp-proof courses is installed.

(6) Masonry unit exposure classifications and corresponding masonry unit applications are as follows:

1. Protected (P) masonry units are suitable for use in locations such as—
   1. internal walls; and
   2. external walls that are coated or rendered; and
   3. walls above damp-proof courses provided the wall is protected at the top by a roof, eaves, coping, topping or the like.
2. General Purpose (GP) masonry units are suitable for use in all locations except those where ‘Exposure class’ (Exp) is required.
3. Exposure class (Exp) masonry units are suitable for use in all locations including severe local conditions such as—
   1. below the damp-proof course in areas where walls are expected to be attacked by salts in the ground water or masonry itself (salt attack or salt damp); and
   2. on sea fronts where walls are exposed to attack from salt spray; and
   3. in heavily polluted areas subject to deposition of atmospheric pollution; and
   4. under regular cyclic freeze and thaw conditions.

Mortar used for masonry construction must comply with AS 3700 or AS 4773 except that the mortar may be mixed by volume in the proportions stated in Table 5.6.3.

(1) Unless otherwise specified, masonry bed and perpend joints must have a nominal thickness of 10 mm.

(2) Raked joints are not to be used in saline environments or areas subject to heavy industrial airborne pollution.

(3) Where raked joints are used the depth of raking must not be—

1. closer than 5 mm to any perforation in cored unit masonry or 20 mm in hollow unit masonry; or
2. more than 5 mm for masonry units at least 90 mm wide; or
3. more than 10 mm for masonry units at least 110 mm wide.

Masonry wall ties must—

1. comply with AS 2699.1 and—
   1. for masonry veneer walls be—
      1. a minimum of light duty veneer ties in areas where the design wind speed is not more than N2; and
      2. a minimum of medium duty veneer ties in areas where the design wind speed is more than N2; and
   2. for cavity masonry walls be—
      1. a minimum of light duty cavity ties in areas where the design wind speed is N1; and
      2. a minimum of medium duty cavity ties in areas where the design wind speed is more than N1; and
   3. where non-engaged piers are provided, piers must be tied to walls using medium duty ties; and
   4. for monolithic or solid masonry construction be a minimum of medium duty ties; and
2. be spaced and fixed in accordance with Tables 5.6.5a, 5.6.5b and 5.6.5c (see also Figures 5.6.5a and 5.6.5b); and
3. be protected against corrosion in accordance with Table 5.6.5d.

(1) Timber door and window frames abutting cavity masonry must be fixed with 300 mm long 30 mm x 0.8 mm kinked galvanised steel straps—

1. fixed to the back of frames; and
2. set into courses not less than 150 mm at not more than 400 mm intervals.

(2) For areas with a wind class of N1 or N2 and a building width from outside wall to outside wall of not more than 10 m in the direction of the roof span (see Figure 5.6.6a), sheet metal and tiled roofs must be tied down using one of the following methods:

1. 30 mm x 0.8 mm galvanised steel straps at not more than 1.2 m centres and corresponding with truss or rafter positions, looped around 10 mm diameter galvanised mild steel rods—
   1. built-in across the cavity at a course not less than 900 mm below the top of the wall; and
   2. embedded not less than 50 mm into each leaf.
2. 30 mm x 1 mm galvanised steel straps at not more than 1.2 m centres and corresponding with truss or rafter positions, built-in to masonry inner leaf not less than 50 mm and at a course not less than 900 mm below the top of the wall (see Figure 5.6.6b).

(3) Roof framing supporting tiled roofs on single leaf unreinforced masonry walls with engaged piers or return walls must have—

1. a built-in 30 mm x 0.8 mm galvanised steel strap fixed to the roof structure that extends the full height of the engaged pier or return wall; and
2. a 4.6 grade M12 galvanised steel rod which is cast into the footing when poured and looped and fixed around the galvanised steel strap required by (a) (see Figure 5.6.6c).

(4) Roof framing supporting sheet roofs on single leaf unreinforced masonry with engaged piers or return walls must have—

1. a built-in 30 mm x 0.8 mm galvanised steel strap fixed to the roof structure extending the full height of the engaged pier or return wall which is looped and fixed around a 4.6 grade 16 mm diameter galvanised steel rod cast into the footing when poured; or
2. a 4.6 grade M16 galvanised steel rod cast into the footing, threaded at the top and extending the full height of the pier or return wall to connect to the roof structure.

Where a lintel is required it must comply with the following:

1. Steel lintels must comply with this Part or H1D6(3).
2. Steel lintels must—
   1. be sized in accordance with Table 5.6.7a; and
   2. be installed with the long leg of lintel angle vertical; and
   3. be wide enough so that the masonry does not overhang the horizontal leg of the lintel by more than 25 mm; and
   4. not support masonry more than 3 m in height when measured above the opening; and
   5. have a minimum bearing length at each end of the lintel of—
      1. for clear spans not more than 1 m - 100 mm; or
      2. for clear spans more than 1 m - 150 mm (See Figure 5.6.7); and
   6. have a minimum of three courses of masonry over openings; and
   7. comply with the corrosion protection requirements of Table 5.6.7b.

(1) Vertical articulation joints must be provided in masonry walls in accordance with (2), except in walls constructed on sites where the soil classification is A or S (see 4.2.2).

(2) Articulation joints between masonry elements must have a width of not less than 10 mm and be provided (see Figures 5.6.8a and 5.6.8b)—

1. in straight, continuous walls with openings less than 900 mm x 900 mm or walls without openings — at not more than 6 m centres and within 4.5 m, but not closer than 470 mm of all corners; and
2. in straight, continuous walls with openings more than 900 mm x 900 mm — at not more than 5 m centres and located so that they are not more than 1.2 m away from openings; and
3. where the height of the wall changes by more than 20% — at the position of change in height; and
4. where a wall changes in thickness; and
5. at control or construction joints in footings or slabs; and
6. at junctions of walls constructed of different masonry materials.

(3) Articulation joints must not be located adjacent to arched openings.

(4) Articulation joints must be filled with flexible sealant that is supported during installation by—

1. a compressible foam or polystyrene filler (see Figures 5.6.8d and 5.6.8e); or
2. a purpose made backer rod (see Figures 5.6.8c, 5.6.8d, 5.6.8e and 5.6.8f).