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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 v24.03:Revision-History; 2021-June

19.11 2021 – June 

The following updates to the NZ Metal Roof and Wall Cladding Code Practice (COP), are effective 1 June 2021.

COP Clauses 11 Natural Light and 14 Installation were comprehensively reviewed and revised for this update. Users are advised to reread those clauses for the most up-to-date information and recommendations.

Other updates included minor fixes to grammar, layout, and updated drawings and dividing 4.9.4 Compatibility Table into smaller, more usable clauses (with no change to recommendations).
 

19.11A Revision Detail - 2021 - June

CategoryClause Number (at time of update)Clause (As of current publication)Details
2 - Editing and rearrangement11 IntroductionUpdate Revisions Message
1 - Minor Errata3.5.23.5.2 Wind LoadSome rewording for clarity.
1 - Minor Errata4.10.14.9.1 Dissimilar MetalsEditing for clarity.
2 - Editing and rearrangement4.10.34.9.4 Compatibility TableThe clause was split for ease of use.
3 - Substantial change to recommendation5.2.2.25.3.2.3 Allowance for Short-Term IntensitiesUpdated Short-term Intensity Factor Explanation.
1 - Minor Errata5.4.25.5.2 Valley DesignUPdated link to the Valley Capacity Calculator.
2 - Editing and rearrangement8.4.4.48.5.5.4 Eaves FlashingInserted a paragraph recommending eaves flashings in Marine Environments.
2 - Editing and rearrangement10.910.9 Minimising Ingress of Water Vapour into the Ceiling CavityClause renamed and revised for clarity.
3 - Substantial change to recommendation1111 Natural LightCOP Clause 11.  Natural Light has been completely revised.
3 - Substantial change to recommendation11.111.1 Clause G7 NZBCCOP Clause 11. Natural Light has been entrile revised.
3 - Substantial change to recommendation11.211.2 Natural Light MaterialsCOP clause 11. Natural Light has been revised, which includes the clause previously titled "Materials".
0 - Clause Removed11.3Types Of Roof LightsThis clause was removed as part of an overall revision of COP clause 11. Natural Light. Illustration of different rooflights can be found in Thermal Expansion and
3 - Substantial change to recommendation11.411.5 Light TransmissionClause has been revised as part of an overall revision of COP Clause 11. Natural Light.
0 - Clause Removed11.5Weathering And DurabilityThis clause has been removed as part of an overall revision of COP Clause 11. Natural Light. Information about translucent sheeting durability can now be found at Natural Light Performance - Durability,
3 - Substantial change to recommendation11.611.3 Performance – StructureClause renamed and content added.
2 - Editing and rearrangement11.6.111.3.1 Point Load on Translucent SheetsClause revised and renamed as part of the overall revision of COP Clause 11. Natural Light.
2 - Editing and rearrangement11.6.211.3.2 Distributed Loads on Translucent SheetingClause revised and renamed as part of the overall revision of COP Clause 11. Natural Light.
3 - Substantial change to recommendation11.711.4 Thermal ResistanceClause has been revised as part of an overall revision of COP Clause 11. Natural Light.
3 - Substantial change to recommendation1414 InstallationCOP Clause 14. Installation has been significantly reviewed and revised.
1 - Minor Errata14.114.11 OverhangDrawing tidy up.
3 - Substantial change to recommendation14.114.1 Pre- InstallationThis clause has been revised as part of an overall revision of COP Clause 14. Installation.
3 - Substantial change to recommendation14.2.214.2.2 OrderingThis clause has been reviewed as part of a substantial revision of COP Clause 14. Installation.
3 - Substantial change to recommendation14.2.314.2.3 TransportationThis clause has been reviewed as part of a substantial revision of COP Clause 14. Installation.
3 - Substantial change to recommendation14.314.3 Accepting DeliveryThis clause has been reviewed as part of a substantial revision of COP Clause 14. Installation.
3 - Substantial change to recommendation14.3.114.3.1 UnloadingThis clause has been reviewed as part of a substantial revision of COP Clause 14. Installation.
3 - Substantial change to recommendation14.3.214.3.2 Wet Storage DamageThis clause has been reviewed as part of a substantial revision of COP Clause 14. Installation.
3 - Substantial change to recommendation14.614.6 Walking On RoofsThis clause has been reviewed as part of a substantial overall revision of COP Clause 14. Installation.
3 - Substantial change to recommendation14.6.114.6.1 FootwearThis clause has been reviewed as part of a substantial revision of COP Clause 14. Installation.
3 - Substantial change to recommendation14.714.7 Strippable FilmsThis clause has been reviewed as part of a substantial revision of COP Clause 14. Installation.
4 - Clause Inserted14.7.114.7.1 Storing Product with Strippable FilmThis clause has been removed as part of a substantial revision of COP Clause 14. Installation. For handling and storage of products with strippable film, please see Strippable Films.
0 - Clause Removed14.7.2Using Strippable FilmThis clause has been removed as part of a substantial revision of COP Clause 14. Installation. For using and handling products with strippable film, please see Strippable Films.
1 - Minor Errata14.914.10 Marking and CuttingThis clause has been reviewed as part of a substantial revision of COP Clause 14. Installation.
2 - Editing and rearrangement14.12.214.13.2 ScrewsAdded "Reduced Diameter Drill Point" to Screw Points. This clause has been reviewed as part of a substantial revision of COP Clause 14. Installation.
1 - Minor Errata14.12.314.13.3 Clip FastenersThis clause has been reviewed as part of a substantial revision of COP Clause 14. Installation.
3 - Substantial change to recommendation14.12.414.13.4 RivetsThis clause has been reviewed as part of a substantial revision of COP Clause 14. Installation.
1 - Minor Errata14.1314.14 Fastener InstallationThis clause has been reviewed as part of a substantial revision of COP Clause 14. Installation.
4 - Clause Inserted14.1514.16 Stop-endsThis clause has been reviewed as part of a substantial revision of COP Clause 14. Installation.
1 - Minor Errata14.1614.17 Turndowns (Drip Forming or Drip Edging) This clause has been reviewed as part of a substantial revision of COP Clause 14. Installation.
1 - Minor Errata14.1814.19 Avoiding ProblemsThis clause has been renamed as part of an overall revision of COP Clause 14. Installation.
3 - Substantial change to recommendation14.18.114.19.1 Roof Cladding DamageThis clause has been reviewed as part of a substantial revision of COP Clause 14. Installation.
3 - Substantial change to recommendation14.18.214.19.2 Water PondingThis clause has been reviewed as part of a substantial revision of COP Clause 14. Installation.
3 - Substantial change to recommendation14.18.314.19.3 Correctly Installed GuttersThis clause has been reviewed as part of a substantial revision of COP Clause .
3 - Substantial change to recommendation14.18.414.19.4 Swarf DamageThis clause has been reviewed as part of a substantial revision of COP Clause 14. Installation.
0 - Clause Removed14.18.4.1Identifying Swarf StainsThis clause has been removed as part of a substantial revision of COP Clause 14. Installation.
3 - Substantial change to recommendation14.18.4.214.19.4.1 Preventing Swarf DamageThis clause has been reviewed as part of a substantial revision of COP Clause 14. Installation.
0 - Clause Removed14.18.4.3Swarf Effect on PerformanceThis clause has been reviewed as part of an overall revision of COP Clause 14. Installation. For more information about swarf effects, please read Swarf Staining and Cut Edge Corrosion.
0 - Clause Removed14.18.4.4Repairing Swarf DamageThis clause has been reviewed as part of an overall revision of COP Clause 14. Installation. For more information about dealing with swarf, see Swarf Damage.
2 - Editing and rearrangement14.18.514.19.5 Colour Matching PaintInserted picture. This clause has been reviewed as part of an overall revision of COP Clause 14. Installation.
2 - Editing and rearrangement14.18.714.19.7 SunscreenInserted photo of sunscreen damage. This clause has been reviewed as part of an overall revision of COP Clause 14. Installation.
0 - Clause Removed14.18.8Removing LichenThis clause has been removed as part of an overall revision of COP Clause 14. Installation. For information about Lichen, see Lichen.
0 - Clause Removed14.18.9Gutter InstallationThis clause has been removed as part of an overall revision of COP Clause 14. Installation. For Information about gutters, see  Gutters.
1 - Minor Errata14.1914.20 Fixing Aluminium SheetingGrammar fix. This clause has been reviewed as part of an overall revision of COP Clause 14. Installation.
1 - Minor Errata14.19.214.20.2 Recommendations for Fixing AluminiumFixed a link.
4 - Clause Inserted 11.8 Flatsheet RooflightsNew clause created as part of an overall revision of COP Clause 11. Natural Light.
4 - Clause Inserted 14.12.2 Side LapsNew clause created as part of a substantial revision of COP Clause 14. Installation.
4 - Clause Inserted 11.7 Stand-Alone RooflightsNew clause created as part of an overall revision of COP Clause 11. Natural Light.
4 - Clause Inserted 11.6 Installing Translucent SheetsNew clause under COP Clause 11. Natural Light.
4 - Clause Inserted  Natural Light Performance - DurabilityNew clause.
4 - Clause Inserted 11.1.1 ComplianceNew clause dealing with natural light and compliance to NZBC G7.
4 - Clause Inserted 19.11 2021 – JuneRevision message for the update on 1 June 2021.