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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 v23.12:Revision-History; 2020-June

19.14 2020 – June 

The following updates to the NZ Metal Roof and Wall Cladding Code Practice (COP), are effective 1 June 2020.

New clauses:

The rest of this update consists of minor improvements, such as tidying up drawings and edits for clarity and grammar.

19.14A Revision Detail - 2020 - June

CategoryClause Number (at time of update)Clause (As of current publication)Details
2 - Editing and rearrangement11 IntroductionUpdate Revisions Message
2 - Editing and rearrangement3.16.43.9.3 Fastener PatternsFastener pattern illustrations updated for clarity - no change to intent.
2 - Editing and rearrangement3.16.53.11.1 Steel Cladding Wind Load Span GraphsClause renamed.
2 - Editing and rearrangement3.16.5.13.11.1.1 Corrugated Steel – 0.40Clause renamed and Fastener pattern illustrations updated for clarity - no change to intent.
2 - Editing and rearrangement3.16.5.33.11.1.2 Corrugated Steel – 0.55Clause renamed and Fastener pattern illustrations updated for clarity - no change to intent.
2 - Editing and rearrangement3.16.5.23.11.1.3 Trapezoidal Five Rib Steel – 0.40 Clause renamed and Fastener pattern illustrations updated for clarity - no change to intent.
2 - Editing and rearrangement3.16.5.43.11.1.4 Trapezoidal Five Rib Steel – 0.55Clause renamed and Fastener pattern illustrations updated for clarity - no change to intent.
2 - Editing and rearrangement3.16.5.53.11.1.5 Trapezoidal Six Rib Steel – 0.40 Clause renamed and Fastener pattern illustrations updated for clarity - no change to intent.
2 - Editing and rearrangement3.16.5.63.11.1.6 Trapezoidal Six Rib Steel – 0.55 Clause renamed and Fastener pattern illustrations updated for clarity - no change to intent.
4 - Clause Inserted 3.11.2 Aluminium Cladding Wind Load Span GraphsNew clause.
4 - Clause Inserted 3.11.2.1 Corrugated Aluminium – 0.70 New Clause for Aluminium Cladding Wind Load Span Graphs.
4 - Clause Inserted 3.11.2.2 Corrugated Aluminium – 0.90New Clause for Aluminium Cladding Wind Load Span Graphs.
4 - Clause Inserted 3.11.2.3 Trapezoidal Five Rib Aluminium – 0.70New Clause for Aluminium Cladding Wind Load Span Graphs.
4 - Clause Inserted 3.11.2.4 Trapezoidal Five Rib Aluminium – 0.90New Clause for Aluminium Cladding Wind Load Span Graphs.
3 - Substantial change to recommendation5.6.35.3.2 Rainfall IntensityClause had been completely revised, with updated Rainfall Intensity Maps at the end of the main Clause, Roof Drainage. 
1 - Minor Errata5.6.3.15.3.2.2 DurationReplaced comparison chart with a simplified one.
2 - Editing and rearrangement8.38.4 Flashing CoverAdded minimum flashing cover values for change of pitch junctions.
4 - Clause Inserted 17 Testing and MRM StandardsNew clause.
2 - Editing and rearrangement1717.1 Metal Cladding TestingClause renamed.
1 - Minor Errata17.5.117.1.5.1 Allowance for VariationFixed "overall" to "over all"
4 - Clause Inserted 17.2 MRM Fastener Performance Requirements and TestingNew clause.
4 - Clause Inserted 17.2.1 Requirements for Fastener TestingNew clause.
4 - Clause Inserted 17.2.2 Test Panel RequirementsNew Clause.
4 - Clause Inserted 17.2.2.1 Test LocationNew Clause.
4 - Clause Inserted 17.2.2.2 Site OrientationNew Clause.
4 - Clause Inserted 17.2.2.3 Preparation of Test PanelNew Clause.
4 - Clause Inserted 17.2.3 Fastener Performance TestingNew Clause.
4 - Clause Inserted 17.2.3.1 Site TestingNew clause.
4 - Clause Inserted 17.2.3.2 Field Performance ValidationNew clause.
4 - Clause Inserted 17.2.3.3 Accelerated TestingNew clause.
4 - Clause Inserted 17.2.3.4 Fastener ShanksNew clause.
4 - Clause Inserted 17.2.3.5 Sealing Washer ConductivityNew clause.
4 - Clause Inserted 17.2.4 AppearanceNew clause.
4 - Clause Inserted 17.2.5 WeatherproofingNew Clause.
4 - Clause Inserted 17.2.6 Fastener Performance Test ReportNew clause.
4 - Clause Inserted 17.3 MRM Soft Edge StandardNew clause.
4 - Clause Inserted 17.3.1 Soft Edge Product Techincal Statement RequirementsNew clause.
4 - Clause Inserted 19.14 2020 – JuneNew clause. Revision detail.
0 - Clause Removed5.5GuttersThe clause had been removed. Gutters are now discussed in more detail in a separate clause for each type, under the main clause Types of Gutter.