Part 12.3 Attachment of framed decks and balconies to external walls of buildings using a waling plate

Part 12.3 applies subject to the limitations set out at H1D11.

Where a deck or balcony relies on the external wall of a building or structure for support, the method of attachment, including any fixings, to the external wall must comply with the following:

1. The deck or balcony’s joist framing members must be supported at the wall by a waling plate.
2. The joist span nearest the external wall must not be more than 3 m (single or continuous span).
3. The size of a waling plate required by (a) must be not less than—
   1. for a timber waling plate—
      1. 140 x 35 mm with a minimum stress grade of F5 or MGP10 when fixed to concrete core-filled masonry using M12 chemical or expanding/mechanical anchors; or
      2. 90 x 35 mm with a minimum stress grade of F5 or MGP10 when fixed to timber frames using No. 14 partial threaded self-drilling screws; or
   2. for a steel waling plate — C15015 (minimum Grade G550) with the web located against the external wall.
4. A waling plate must be attached so that—
   1. for core-filled reinforced concrete masonry external walls, fixings are staggered along the waling plate at not more than 300 mm centres measured along the waling plate; and
   2. for timber external wall frames, two No. 14 Type screws are provided—
      1. into a solid joist or bearer framing member that is not less than 90 x 45 mm with a minimum stress grade of F5 or MGP10; and
      2. for deck construction— at not more than 450 mm centres measured along the waling plate; and
      3. for tiled balcony construction— at not more than 400 mm centres measured along the waling plate; and
   3. for steel framed external walls, two fixings are provided into a joist or bearer framing member not less than C20015 (Grade G550) at not more than 300 mm centres measured along the waling plate; and
   4. fixings are installed within 300 mm of each end of the waling plate, and in accordance with the following (as applicable):
      1. For a timber waling plate — deck construction: two No. 14 partial threaded self-drilling screws at not more than 450 mm centres and not located within 65 mm from the ends or within 30 mm from the top and bottom edges.
      2. For a timber waling plate — deck construction: M12 chemical or expanding/mechanical anchors at not more than 400 mm centres and not located within 120 mm from the ends or within 60 mm from the top and bottom edges.
      3. For a timber waling plate — tiled balcony construction: two No. 14 partial threaded self-drilling screws at not more than 400 mm centres and not located within 65 mm from the ends or within 30 mm from the top and bottom edges.
      4. For a timber waling plate — tiled balcony construction: M12 chemical or expanding/mechanical anchors at not more than 300 mm centres and not located within 120 mm from the ends or within 60 mm from the top and bottom edges.
      5. For a steel waling plate — not located within 50 mm from the ends or within 30 mm from the top and bottom edges.
5. Fixings for attaching a waling plate to an external wall must be—
   1. for timber external wall frames with a minimum stress grade of F5 or MGP 10, No. 14 partial threaded self-drilling screws so that each screw is embedded not less than 44 mm into the joist or bearer member (see Figure 12.3.2a); and
   2. for steel external wall frames, 8.8/S M12 bolts with not less than 3 mm thick 55 mm diameter washers; and
   3. for a core-filled masonry external wall, 4.6/S M12 chemical or expanding/mechanical anchors with—
      1. a minimum 2 kN working load capacity in shear and 1.5 kN in tension; and
      2. not less than 3 mm thick 55 mm diameter washers placed on the waling plate under the anchor head (see Figure 12.3.2b).
6. Fixings used for attaching waling plates to external walls must be—
   1. stainless steel where the building is located within 200 m of breaking surf; or
   2. hot-dipped galvanised, stainless steel or monel metal for all other areas.

Where the wall cladding is removed to attach a waling plate, openings in external wall cladding exposed to the weather must be flashed with materials complying with AS/NZS 2904 and in accordance with the following:

1. Flashings must be provided to bottom, tops and the sides of the junction of the waling plate and the external wall, and must be installed so that the flashing—
   1. extends not less than 150 mm beyond each side of the waling plate where practicable; and
   2. is attached to the waling plate and wall framing; and
   3. at the top and bottom of the waling plate, drains to the outside face of the wall or cladding.
2. Joins in the flashing must—
   1. overlap by not less than 75 mm in the direction of flow; and
   2. be securely fastened at intervals of not more than 40 mm; and
   3. have sealant installed between laps.
3. The method of flashing must be suitable for the framing and cladding used.
4. Flashings must be securely fixed at least 25 mm under the cladding at ends and edges of the framing of the opening.

Where a deck or balcony is more than 1 m off the ground when measured from the uppermost surface of the deck or balcony at any point to the top of any supporting footing, bracing must be installed as follows:

1. Two diagonally opposed 30 x 0.8 mm galvanized steel straps must be installed across the top or underside of the joists and be attached using one fixing at—
   1. each joist or equivalent framing member; and
   2. the waling plate.
2. A secondary set of 30 x 0.8 mm steel straps must be installed using one fixing at each joist or equivalent framing member in accordance with Figure 12.3.4 where the deck or balcony extends more than 4 m from the external wall.
3. The steel straps must—
   1. be continuous and extend diagonally at an angle between 30° to 60°; and
   2. span not more than 4 m when measured along a line at a right angle from the external wall.
4. Fixings for the steel straps must be—
   1. for timber framing, 50 x 3.15 hot-dipped galvanized flat head ring shank or flat head deformed nail; or
   2. for steel framing, 8-18 self embedding head or wafer head screws.
5. Where the deck or balcony is located within a severe corrosion environment, the bracing and fixings must comply with Table 6.3.9a, 6.3.9b and 6.3.9c.