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Disclaimer

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.

Scope

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 v24.09:Revision-History; V2409-September-2024

19.1 v24.09 September 2024 

The latest changes to the NZMRM Metal Roof and Wall Cladding Code of Practice; published on 1 September 2024.

Category 3: Substantial Changes to Recommendations.

  • 8.5.1 Ridge and Hip Intersections
    Changed the requirement for butyl membranes, underlay, or soft flashing for weathertightness to a recommendation as a secondary method in addition to good design and installation.
  • 5.4.2.3 Spouting Support Systems
    Clarifying recommendation: brackets for pre-painted spouting in marine conditions must be appropriately painted or powder-coated before installation, or non-ferrous metals should be used.

Category 2: Editing and Rearrangement

19.1A Revision Detail v24.09 - 2024 -September

CategoryClause Number (prior to update)Clause (As of current publication)Details
2 - Editing and rearrangement11 IntroductionUpdated Revisions Message
1 - Minor Errata4.34.3 Metal PerformanceMinor revision to improve clarity, conciseness, style, or layout. No changes to recommendations.
1 - Minor Errata4.64.6 Environmental CategoriesMinor revision for style, grammar, and clarity. No changes to recommendations.
1 - Minor Errata4.10.34.10.3 Solar Collectors and Other Roof Mounted StructuresResizing of photos for consistency. No changes to recommendations.
1 - Minor Errata4.10.64.10.6 Capillary ActionMinor edit for style, grammar, clarity, or consistency. No changes to recommendations.
1 - Minor Errata4.144.14 Swarf Staining and Cut Edge CorrosionResized photos for consistency and layout. No changes to recommendations.  
1 - Minor Errata4.154.15 ClearancesIllustration reformatting. No changes to recommendations.
1 - Minor Errata4.15.14.15.1 Ground ClearanceIllustration reformatting. No changes to recommendations.
1 - Minor Errata4.18.24.18.2 Post-Painted Factory Applied finishMinor edit to improve clarity, conciseness, style, or layout. No changes to recommendations.
2 - Editing and rearrangement5.4.2.35.4.2.3 Spouting Support SystemsEditing to clarify the requirement for pre-painting spouting brackets.
1 - Minor Errata8.48.4 Flashing CoverFixed typo. changed "m" to "mm".
2 - Editing and rearrangement8.4.48.4.4 Flashing LapsClarified the recommendation for unsealed laps to have a minimum of 150 mm cover and sealed laps a minimum of 100 mm.
3 - Substantial change to recommendation8.5.18.5.1 Ridge and Hip Intersections
  • Renamed clause to Ridge and Hip Intersections.
  • Changed the requirement for butyl membranes, underlay, or soft flashing for weathertightness to a recommendation as a secondary method in addition to good design and installation.
1 - Minor Errata15.1.615.1.6 DurabilityFixed the spelling of soffit. No changes to recommendations.
2 - Editing and rearrangement18.218.2 Pitch & Rise CalculatorAdded pitches to the table above 60°
4 - Clause Inserted 19.1 v24.09 September 2024A new clause providing details of the updates published on 1 September 2024.