The NZ Metal Roof and Wall Cladding Code of Practice (COP) is published by NZ Metal Roofing Manufacturers Inc. (MRM), to provide:
- acceptable trade practice for the fixing of metal roof and wall cladding and accessories.
- prescriptive detailing for designers and sets a benchmark for the standard of detailing and workmanship required over and above that required to comply with the NZBC.
The COP does not describe or dismiss alternative methods, which may need specific acceptance by the Building Consent Authorities.
It is published in accordance with current technology, materials, and building codes. The COP will be periodically updated to reflect changes in legislation and standards or improvements in technology and available materials.
The most current Code of Practice is available on the MRM website, www.metalroofing.org.nz/cop, as Code of Practice Online (MRM COP Version 23.12).
The latest update to the NZMRM Code of Practice, v23.12 was published on 1 December 2023.
Substantial change to recommendations:
- 15.1 Curved Roofs and all its sub-clauses have been substantially reviewed and revised.
- 8.4 Flashing Cover:
- Added clarification of rib cover to Apron Flashing Cover — Trapezoidal.
- Changed rib height for minimum flashing cover from 25 mm to 20 mm.
- Changed recommendation for longitudinal flashings to include both apron and barge flashings.
- Added Category D for SED in Wind Zones up to 68 m/s.
Notable Editing and rearrangement:
- 15.4.2 Tray Roofing Profiles: This clause has been renamed and editied to clarify the difference between tray roofing and standing seam roofing.
- 15.4.4 Tray Roofing Weathertightness: A clause has been added on weathertightness of standing seam roofs.
- 15.4.3 Tray Roofing Design: This clause has been renamed and some of the content revised.
- 15.4.5 Tray Fixings: Content editing for clarity.
- 14.3.2 Wet Storage Damage: Added content for dealing with Blooming.
- 22.214.171.124 Ridge – barge Intersections: New Illustration showing a 126.96.36.199D Head-Barge/Ridge/Barge Junction.
- 8.4.1 Apron Upstands: Inserted an illustration to show Undertray for additional upstand.
The rest of the updates consisted of some renamed clauses, and minor corrections and edits.For more detailed information, see 19.1 v23.12 – December 2023.