Metalcraft Roofing supply the Kāhu® system as a horizontal and vertical external wall cladding, and for roofs with a defined minimum pitch of 3 degrees for use on commercial and residential buildings within the following scope:

Location:

• In wind zones:
  • Up to and including Extra High as defined by NZS-3604:2011
  • Subject to specific engineering, if the engineer has satisfied themselves that the product, pitch and fixings will meet the conditions
• In all climate zones as defined by NZS-3604:2011, subject to the limitations set out below
• On buildings located within 1m of the relevant boundary, in respect of fire spread only

Building;

• On new buildings that have been designed and constructed to comply with the NZ Building Code (NZBC) using timber or steel framing
• On existing buildings using timber and steel framing where the designer and installer have satisfied themselves that the building is suitable for the intended building work
• In conjunction with a vapour permeable building wrap that has a permeability of 36g/m2/day of a vapour resistance of no more than 500MNs/g
• Can be used in conjunction with a potable water collection system

Location:

• Kāhu® may be used as a roof cladding system in exposure zones B, C & D as defined in Sec 4, NZS3604:2011. For use in 'Microclimatic considerations', (as defined in Sec 4.2.4) refer to  Metalcraft Roofing
• Kahu® may be used as a wall cladding system in exposure zones B & C. Where Kāhu is to be used in exposure Zone D, then only Colorsteel® Endura® or Colorsteel® Maxx® may be used

Building:

• Where Kāhu® is used in an insulated building in conjunction with steel framing, a thermal break is required
• Contact with other materials must be in accordance with Table 21 (E2/AS1), or compatible with the The New Zealand Metal Roofing Manufacturers Association Inc (NZMRM) Code Of Practice
• Building height and design wind speed is limited by the Kāhu® design load span tables
• Where it is used as a roof cladding system, Kāhu® sheet lengths of ≤40m must be installed on a roof with a minimum pitch of 3°. Kāhu sheet lengths of >40m but ≤60m must be installed on a roof with a minimum pitch of 4°
• When installed vertically as a wall cladding, Kāhu® may be direct-fixed up to a risk score of 12 when risk calculation relies on the E2/AS1 risk matrix methodology
• When installed horizontally or vertically as a wall cladding, Kāhu® must always be installed in conjunction with a drained cavity

If designed, installed and maintained in accordance with all Metalcraft Roofing requirements, the Kāhu® Roofing and External Cladding system will comply with or contribute to compliance  with the following provisions of the New Zealand Building Code:

• B1 Structure: B1.3.1, B1.3.2, B1.3.3 (a, b, c, d, g, i)
• B2 Durability: B2.3.1 (b)
• C3 Fire Affecting Areas Beyond the Fire Source: C3.4(a), C3.5, C3.7 (a)
• E2 External Moisture: E2.3.1, E2.3.2, E2.3.7 (a-c)
• F2 Hazardous Building Materials: F2.3.1

See product technical statement for full information.

• Kāhu® Roofing and External Cladding system will not contaminate potable water — AS/NZS 4020:2005