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Although the information contained in this Code has been obtained from sources believed to be reliable, New Zealand Metal Roofing Manufacturers Inc. makes no warranties or representations of any kind (express or implied) regarding the accuracy, adequacy, currency or completeness of the information, or that it is suitable for the intended use.

Compliance with this Code does not guarantee immunity from breach of any statutory requirements, the New Zealand Building Code or relevant Standards. The final responsibility for the correct design and specification rests with the designer and for its satisfactory execution with the contractor.

While most data have been compiled from case histories, trade experience and testing, small changes in the environment can produce marked differences in performance. The decision to use a particular material, and in what manner, is made at your own risk. The use of a particular material and method may, therefore, need to be modified to its intended end use and environment.

New Zealand Metal Roofing Manufacturers Inc., its directors, officers or employees shall not be responsible for any direct, indirect or special loss or damage arising from, as a consequence of, use of or reliance upon any information contained in this Code.

New Zealand Metal Roofing Manufacturers Inc. expressly disclaims any liability which is based on or arises out of the information or any errors, omissions or misstatements.

If reprinted, reproduced or used in any form, the New Zealand Metal Roofing Manufacturers Inc. (NZMRM) should be acknowledged as the source of information.

You should always refer to the current online Code of Practicefor the most recent updates on information contained in this Code.


This Code of Practice provides requirements, information and guidelines, to the Building Consent Authorities, the Building Certifier, Specifier, Designer, Licensed Building Practitioner, Trade Trainee, Installer and the end user on the design, installation, performance, and transportation of all metal roof and wall cladding used in New Zealand.

The calculations and the details contained in this Code of Practice provide a means of complying with the performance provisions of the NZBC and the requirements of the Health and Safety at Work Act 2015.

The scope of this document includes all buildings covered by NZS 3604, AS/NZS 1170 and those designed and built under specific engineering design.

It has been written and compiled from proven performance and cites a standard of acceptable practice agreed between manufacturers and roofing contractors.

The drawings and requirements contained in this Code illustrate acceptable trade practice, but recommended or better trade practice is also quoted as being a preferred alternative.

Because the environment and wind categories vary throughout New Zealand, acceptable trade practice must be altered accordingly; in severe environments and high wind design load categories, the requirements of the NZBC will only be met by using specific detailing as described in this Code.

The purpose of this Code of Practice is to present both Acceptable Trade Practice and Recommended Trade Practice, in a user-friendly format to ensure that the roof and wall cladding, flashings, drainage accessories, and fastenings will:

  • comply with the requirements of B1, B2, E1 E2 and E3 of the NZBC;
  • comply with the design loading requirements of AS/NZS 1170 and NZS 3604 and with AS/NZS 1562;
  • have and optimised lifespan; and
  • be weathertight.

COP v24.06:Safety; Working-Height

13.4 Working At Height 

Source: Worksafe: Working at Height in New Zealand.

Many falls from heights are caused by a lack of planning. Dangerous situations can be improved by identifying, assessing, and managing hazardous situations.

13.4.1 Scaffolding 

Scaffolds are a common way to provide a safe work platform.

  • Scaffolds must comply with the Scaffolding, Access & Rigging New Zealand (SARNZ) Best Practice Guidelines for Scaffolding in New Zealand or equivalent guidelines or a higher standard.
  • Scaffolds should be erected, altered and dismantled only by persons who have been trained and have suitable experience with the type of scaffolding in use.

13.4.2 Roof Edge Protection 

Edge protection is used to prevent persons, objects, or materials from falling.

Edge protection may be:

  • a proprietary (engineered) system,
  • materials to form a guardrail or physical barriers,
  • erected scaffolding that supports a temporary edge protection system, or
  • a combination of solutions.


13.4.3 Safety Mesh 

Safety mesh protects workers against falling through a roof while they are installing cladding; it should be used in combination with appropriate edge protection. For more information about using Safety Mesh, see

Safety mesh should comply with AS/NZS 4389 Safety Mesh.


13.4.4 Safety Netting 

Safety netting describes fall arrest systems using temporary netting.  This must be designed and installed in compliance with Worksafe: Best Practice Guidelines, Safe use of Safety Nets.

13.4.5 Mechanical Access Plant 

Mechanical Access Plant includes:

  • mobile elevated work platforms,
  • forklift platforms,
  • crane lift platforms, and
  • knuckle booms

13.4.6 Safety Harness 

Safety harnesses may be of Total Restraint type or fall arrest type.

Total Restraint types are preferable, they protect a person from approaching an unprotected edge

Fall arrest or Positioning systems limit the distance a person can fall

All safety harness systems must be adequately anchored, and in fall arrest systems rescue planning must be developed prior to use.

13.4.7 Soft Landing Systems 

These mitigate the effect of falls by providing an energy absorbing landing area.  They are generally applied where potential fall height is low.