NCC 2016 Volume Two
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Part 3.5.3 Wall Cladding

Part 3.5.3 Wall Cladding

Appropriate Performance Requirements

Appropriate

Where an alternative wall cladding is proposed as a Performance Solution to that described in Part 3.5.3, that proposal must comply with—

  1. P2.1.1 ; and
  2. P2.2.2 ; and
  3. the relevant Performance Requirements determined in accordance with 1.0.7.

Acceptable construction manuals

3.5.3.0

P2.1.1 and P2.2.2 are satisfied for wall cladding if it is designed and constructed in accordance with one of the following, as appropriate:

(a)

Metal wall cladding: AS 1562.1.

(b)

Autoclaved aerated concrete: AS 5146.1.

Acceptable construction practice

3.5.3.1 Application

Compliance with this acceptable construction practice satisfies Performance RequirementsP2.1.1 and P2.2.2 for wall cladding provided—

(a)

the building is located in an area with a design wind speed of not more than N3; and

Explanatory information

Explanatory information:
  1. Information on design wind speeds for particular areas may be available from the appropriate authority.
  2. A map indicating cyclonic regions of Australia is contained in Part 3.10.1.
  3. For wall cladding in areas with a design wind speed of more than N3 refer to the appropriate design manual listed in Part 3.11.
(b)

wall cladding is installed in accordance with—

(i)

for timber cladding; and

(ii)

for fibre-cement and hardboard wall cladding boards; and

(iii)

for fibre-cement, hardboard and plywood sheet wall cladding; and

(c)

fibre-cement sheet eaves are installed in accordance with 3.5.3.5; and

(d)

openings in cladding are flashed in accordance with 3.5.3.6.

3.5.3.2 Timber cladding

Timber cladding must be installed as follows:

(a)

Splayed timber weatherboards must be fixed in accordance with Figure 3.5.3.1 and with a lap not less than—

(i)

30 mm for hardwood, Cypress and treated pine; and

(ii)

20 mm for Western Red Cedar; and

(iii)

25 mm for Baltic Pine.

(b)

Profiled timber boards must be—

(i)

fixed in a horizontal, vertical or diagonal direction with the overlap and groove closely fitted, where provided; and

(ii)

with tongue and groove profile, fixed tongue edge up, where they are fixed in a horizontal or diagonal direction; and

(iii)

with a vapour permeable sarking installed behind boards, where they are fixed in a vertical or diagonal direction (see Figure 3.5.3.2).

(c)

Spacing of fixings must be—

(i)

for splayed timber weatherboards and profiled timber boards not more than 130 mm wide, one fixing at each stud or equivalent framing member, at not more than 650 mm centres measured along the board; and

(ii)

for profiled timber boards greater than 130 mm wide, two fixings at each stud or equivalent framing member, at not more than 650 mm centres measured along the board; and

(iii)

fixed so that the fixing does not penetrate the tip or thinner edge of the board beneath, i.e. for 30 mm lap, fix 35 mm from the butt (see Figure 3.5.3.1).

(d)

Fixings used for timber cladding must comply with the following:

(i)

Where fixings are punched or countersunk and filled prior to painting, fixings must be standard steel bullet-head nails or standard steel self embedding head screws.

(ii)

Uncoated copper or steel fixings must not be used for Western Red Cedar (silicon bronze, monel metal, stainless steel or hot-dipped galvanised are suitable).

(iii)

In all other cases, fixings must be hot-dipped galvanised flat head or bullet head nails or hot-dipped galvanised self embedding head or wafer head screws.

(e)

Acceptable fixing sizes are—

(i)

for hardwood and Cypress frames—

(A)

50×2.8 mm plain shank nails; or

(B)

8–18×50 mm self embedding head or wafer head screws; and

(ii)

for softwood frames—

(A)

50×3.15 mm annular threaded nails; or

(B)

8–18×50 mm self embedding head or wafer head screws.

(iii)

for steel frames 8–18×30 mm self embedding head or wafer head screws.

3.5.3.3 Wall cladding boards

Wall cladding boards must—

(a)

for 7.5 mm (minimum) thick fibre-cement — comply with AS/NZS 2908.2 or ISO 8336; and

(b)

for 9.5 mm (minimum) thick hardboard — comply with AS/NZS 1859.4; and

(c)

be fixed in accordance with Table 3.5.3.1 and Figure 3.5.3.1.

Table 3.5.3.1 FIXING REQUIREMENTS FOR WALL CLADDING BOARDS

Material Maximum stud spacing (mm) Minimum lap (mm) Stud fixings (mm)
Timber Steel
Minimum 7.5 mm thick fibre-cement 600 25 40×2.8 G (8–18)×35 S
Minimum 9.5 mm thick hardboard 600 20 50×2.8 GC (8–18)×35 S

Legend:

G = Galvanised fibre-cement nail
GC = Galvanised clout or flathead nail
S = Self embedding head screw

Figure 3.5.3.1

FIXING OF WALL CLADDING

Diagram a. Timber Cladding Diagram b. Wall Cladding Boards
v2_Fig3531a_2008.svg
v2_Fig3531b_2006.svg

Figure 3.5.3.2

FIXING OF VERTICAL WALL CLADDING

v2_fig3532_2016.svg
Note: For fixing of diagonal wall cladding, equivalent fixing details apply.

3.5.3.4 Sheet wall cladding

(a)

Fibre-cement sheet wall cladding must—

(i)

comply with AS/NZS 2908.2 or ISO 8336; and

(ii)

be fixed in accordance with Table 3.5.3.2 and Figure 3.5.3.3; and

(iii)

where also acting as structural bracing, be installed using the lesser of the stud and fixing spacings for both applications.

Table 3.5.3.2 STUD AND FIXING SPACINGS FOR 6 mm FIBRE-CEMENT SHEET WALL CLADDING

Design wind speed Maximum stud spacing Maximum nail spacing (2.8 mm fibre-cement nails)
Within 1200 mm of the external corners of the building Elsewhere Within 1200 mm of the external corners of the building Elsewhere
Body Edges Body Edges
N1 600 600 300 200 300 200
N2 600 600 200 200 300 200
N3 450 600 200 200 200 200

Figure 3.5.3.3

SHEET FIXING DETAIL

v2_Fig3533_2016.svg
(b)

Hardboard sheet wall cladding must—

(i)

comply with AS/NZS 1859.4; and

(ii)

be fixed in accordance with Table 3.5.3.3; and

(iii)

where also acting as structural bracing, be installed using the lesser of the stud and fixing spacings for both applications.

Table 3.5.3.3 STUD AND FIXING SPACINGS FOR 9.5 mm HARDBOARD SHEET WALL CLADDING

Design wind speed Maximum stud spacing Maximum nail spacing (2.8 mm fibre-cement nails)
Within 1200 mm of the external corners of the building Elsewhere Within 1200 mm of the external corners of the building Elsewhere
Body Edges Body Edges
N1 600 600 300 150 300 150
N2 600 600 300 150 300 150
N3 600 600 300 150 300 150
Note: Fixings must be positioned a minimum of 12 mm from the edge of the sheet.
(c)

Structural plywood wall cladding must—

(i)

comply with AS/NZS 2269; and

(ii)

be fixed in accordance with the following:

(A)

Where structural plywood acts as combined cladding and structural bracing it must comply with Table 3.5.3.4.

(B)

Sheets not more than 9 mm thick must be fixed using 2.8 or 3.5×30 mm long galvanised clouts or flat head nails spaced at—

(aa)

150 mm centres along sheet edges; and

(bb)

300 mm for intermediate fixings.

(C)

Sheets more than 9 mm thick must be fixed with 2.8 or 3.5 mm galvanised clouts or flat head nails with a length calculated using the following formula:

Minimum nail length (L) = plywood thickness + (10 x diameter of nail)

(D)

The fixings must be located not less than 9 mm from the edge of the sheet.

Explanatory information

Explanatory information:

The above formula is applied as follows:

For 12 mm plywood and 2.8 mm diameter nail.

L = 12 + 28 mm; therefore the nail length must be 40 mm.

Table 3.5.3.4 MINIMUM STRUCTURAL PLYWOOD THICKNESS FOR COMBINED BRACING AND EXTERNAL CLADDING (mm)

Plywood stress grade Stud spacing (mm)
Plywood face grain parallel to studs Plywood face grain at right angles to studs
450 600 900 450 600 900
F8 9 12 16 7 9 12
F11 8 12 16 6 8 12
F14 7 12 16 6 7 12

3.5.3.5 Eaves and soffit linings

External fibre-cement sheets and linings used as eaves and soffit linings must—

(a)

comply with AS/NZS 2908.2 or ISO 8336; and

(b)

be fixed in accordance with Table 3.5.3.5 and Figure 3.5.3.4 using—

(i)

2.8×30 mm fibre-cement nails; or

(ii)

No. 8 wafer head screws (for 4.5 mm and 6 mm sheets only); or

(iii)

No. 8 self embedding head screws (for 6 mm sheets only).

Table 3.5.3.5 TRIMMER AND FASTENER SPACINGS FOR 4.5 AND 6 mm FIBRE-CEMENT EAVES AND SOFFIT LININGS

Maximum eaves width Design wind speed Maximum trimmer spacings (mm) Maximum fastener spacings (mm)
Within 1200 mm of the external corners of the building Elsewhere Within 1200 mm of the external corners of the building Elsewhere
600 N1 600 900 200 300
N2 600 800 200 300
N3 500 700 200 300
1200 N1 600 750 200 300
N2 600 700 200 300
N3 500 650 200 300

Figure 3.5.3.4

EAVES TRIMMER DETAIL

v2_Fig3534_2016.svg

3.5.3.6 Flashings to wall openings

Openings in external wall cladding exposed to the weather must be flashed as follows:

(a)

All openings must be adequately flashed using materials that comply with AS/NZS 2904.

(b)

Flashings must be securely fixed at least 25 mm under the cladding and extend over the ends and edges of the framing of the opening (see Figure 3.5.3.5).

Figure 3.5.3.5

TYPICAL WINDOW FLASHING DETAIL

v2_Fig3535_2016.svg