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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 v24.12:Revision-History; 2019-August

2019 – August

19.21 2019 – August

The following updates to the NZ Metal Roof and Wall Cladding Code Practice (COP), are effective 1 August 2019.

Major Revisions

The main clause 17.1 Metal Cladding Testing was substantially revised to give more practical guidance for testing in accordance with the NZ MRM Code of Practice.
The main clause 13 Safety has been substantially revised and updated to closer reflect the Health and Safety at Work Act 2015, referencing the documents Worksafe: Working on Roofs and Worksafe: Working at Height in New Zealand.
The sub-clause 14.20A Fixing Aluminium has been substantially revised to better reflect good trade practice and manufacturers’ recommendations.

Summary of other changes in this update

9.4 Penetration Design has been reorganised so sheetmetal back curb designs are now shown in different clauses for corrugated and trapezoidal profiles.
9.4 Penetration Design now includes an easy-use-use guide for penetration flashing design.
Previously missing design details have been added for 9.4.2.6F Cricket Under-Soaker: Trapezoidal and 9.4.2.6D Arrowhead Under-Soaker: Trapezoidal.
Trough Section and Standing Seam have been added to 3.4 Profiles descriptions in Structure.

19.21A Revision Detail - 2019 - August

Category	Clause Number (at time of update)	Clause (As of current publication)	Details
4 - Clause Inserted		19.21 2019 – August	Summary of Changes – August 2019
1 - Minor Errata	10.5	10.5 Building Airtightness	Minor erata: changed 36.2 to 3602
0 - Clause Removed	9.4	Penetration Positioning	Clause is now included in Penetration Design.
2 - Editing and rearrangement	9.5	9.4 Penetration Design	Revised clause. Penetration Positioning is now included in this clause.
1 - Minor Errata	14.8	14.9 Setting Out	Typo correction
4 - Clause Inserted	9.6	9.5 Boot Flashings	Changed the word profile to profiles for consistency with the rest of the document.
4 - Clause Inserted		9.4.2.4 Penetration Flashings Reference	New clause to compare penetration flashing options.
2 - Editing and rearrangement	9.5.3	9.4.1.2 Under-Soaker Back Flashings	Clause renamed for consistency.
1 - Minor Errata	9.5.4.3	9.4.2.3 Cricket Back Curbs	Changed kerb to curb for consistency.
1 - Minor Errata	8.3	8.4 Flashing Cover	Corrected a misprint, removed <20mm from aprons, category B.
1 - Minor Errata	14.13.4	14.14.4 Fastener Allowance for Expansion	Fixed 8 mm for style consistency.
2 - Editing and rearrangement	14.12.1	14.13.1 Nails	Photo of Nail Pull-Out inserted.
4 - Clause Inserted		14.20.1 Painted Aluminium	Newly created clause dealing with Painted Aluminum products
4 - Clause Inserted		14.20.2 Recommendations for Fixing Aluminium	Newly created clause setting out COP recommendations for fixing aluminium claddding.
0 - Clause Removed	13	Site Practice	Clause removed. Topics previously discussed in Site Practice is now dealt with in more detail in various clauses under Installation.
3 - Substantial change to recommendation	13.1	13 Safety	Safety has been updated in accordance with the Health and Safety at Work Act 2015 (HSWA 2015).
3 - Substantial change to recommendation	13.1.1	13.2 Responsibilities	Clause updated in accordance with the Health and Safety at Work Act (HSWA) 2015.
3 - Substantial change to recommendation	13.1.7	13.4.1 Scaffolding	Clause has been substantially revised in accordance with Worksafe: Working at height in New Zealand.
3 - Substantial change to recommendation	13.1.10	13.4.3 Safety Mesh	This clause has been substantially revised in accordance with Worksafe: Working at Height in New Zealand.
4 - Clause Inserted		13.4.6 Safety Harness	New clause.
4 - Clause Inserted		13.4.7 Soft Landing Systems	New clause.
2 - Editing and rearrangement	14.21	14.22 Tools Of The Trade	Picture added: Turn Up and Turn Down Tools.
2 - Editing and rearrangement	9.5.2	9.4.1.1 Over-Flashed (Watershed) Back Flashings	Clause has been renamed.
0 - Clause Removed	13.1.2	Training	Clause removed. Whole main clause (Safety) has been substantially revised in accordance with HSWA 2015 and Worksafe guidelines.
0 - Clause Removed	13.1.5	Limitations Of Fall Arrest And Travel Restraint	Clause removed. Whole main clause (Safety) has been substantially revised in accordance with HSWA 2015 and Worksafe guidelines.
0 - Clause Removed	13.1.4	Residential And Light Commercial Roofing	Clause removed. Whole main clause (Safety) has been substantially revised in accordance with HSWA 2015 and Worksafe guidelines.
0 - Clause Removed	13.1.13	Roof Access During Construction	Clause removed. Whole main clause (Safety) has been substantially revised in accordance with HSWA 2015 and Worksafe guidelines.
0 - Clause Removed	13.1.12	Joining Safety Mesh	Clause removed. Whole main clause (Safety) has been substantially revised in accordance with HSWA 2015 and Worksafe guidelines.
0 - Clause Removed	13.1.11	Steel Fixing	Clause removed. Whole main clause (Safety) has been substantially revised in accordance with HSWA 2015 and Worksafe guidelines.
0 - Clause Removed	13.1.9	Personal Safety	Clause removed. Whole main clause (Safety) has been substantially revised in accordance with HSWA 2015 and Worksafe guidelines.
0 - Clause Removed	13.1.8	Mobile Scaffolds	Clause removed. Whole main clause (Safety) has been substantially revised in accordance with HSWA 2015 and Worksafe guidelines.
0 - Clause Removed	13.1.6	Access	Clause removed. Whole main clause (Safety) has been substantially revised in accordance with HSWA 2015 and Worksafe guidelines.
4 - Clause Inserted		13.4.5 Mechanical Access Plant	New clause.
4 - Clause Inserted		13.4.4 Safety Netting	New clause.
4 - Clause Inserted		13.3.3 Weather Conditions	New clause.
4 - Clause Inserted		13.3.2 Assessment of Existing Roof Cladding	New clause.
4 - Clause Inserted		13.3.1 Safe Access to Roofs	New clause.
4 - Clause Inserted		13.3 Working on Roofs	New clause.
4 - Clause Inserted		13.2.4.1 Other People's Responsibilities	New clause.
4 - Clause Inserted		13.2.4 Other People	New clause.
4 - Clause Inserted		13.2.1 PCBU	New clause.
4 - Clause Inserted		13.2.3.1 Workers' Responsibilities	New clause.
4 - Clause Inserted		13.2.3 Workers	New clause.
4 - Clause Inserted		13.2.2.1 Officer Responsibilities	New clause.
4 - Clause Inserted		13.2.2 Officers	New clause.
4 - Clause Inserted		13.2.1.1 PCBU Responsibilities	New clause.
4 - Clause Inserted	9.5.5	9.4.2.5 Penetration Flashings on Corrugated Profiles	This clause has been revised and renamed to specifically show sheetmetal flashings on corrugated profiles.
4 - Clause Inserted		3.15.4 Standing Seam	New clause.
4 - Clause Inserted		3.4.4 Secret-fixed Profiles	New clause.
2 - Editing and rearrangement	14.3.2	14.3.2 Wet Storage Damage	Removed reference to "Fretting".
2 - Editing and rearrangement	2.1	2.1 Definitions	Updated Glossary item: "Fretting"
2 - Editing and rearrangement	4.12	4.11 Inert Catchment	Inserted photo "Localised Damage due to Inert Catchment".
1 - Minor Errata	14.4	14.4 Site Safety	Fixed link: Safety
1 - Minor Errata	14.5	14.5 Handling	Minor grammatical fix.
1 - Minor Errata	14.7.1	14.7.1 Storing Product with Strippable Film	Grammar fix.
1 - Minor Errata	14.7.2	14.7.2 Using Strippable Film	Grammar fix.
1 - Minor Errata	14.1	14.11 Overhang	Drawing tidy up.
4 - Clause Inserted		17.1 Metal Cladding Testing	New Clause, to replace Testing.
4 - Clause Inserted		17.1.1 Standards: AS Standards and COP Testing Standard	New clause.
4 - Clause Inserted		17.1.2 Test Requirements	New Clause
4 - Clause Inserted		17.1.2.1 Supporting Structure and Equipment	New Clause
4 - Clause Inserted		17.1.2.2 Test Set-up	New clause.
4 - Clause Inserted		17.1.2.2.1 Number of Specimens	New clause.
4 - Clause Inserted		17.1.2.2.2 Width of Specimen	New clause.
4 - Clause Inserted		17.1.2.2.3 Number of Spans	New clause.
4 - Clause Inserted		17.1.3 Testing Procedure	New clause.
4 - Clause Inserted		17.1.3.1 UDL Testing	New clause.
4 - Clause Inserted		17.1.5 Publishing Results	New clause.
4 - Clause Inserted		17.1.5.1 Allowance for Variation	New clause.
0 - Clause Removed	17	Testing	The entire clause Testing has been substantially revised and published as Structural Testing to give better guidance on testing according to the Code of Practice Standards.
0 - Clause Removed	17.2	Background to Scope	The entire clause Testing has been substantially revised and published as Structural Testing to give better guidance on testing according to the Code of Practice Standards.
0 - Clause Removed	17.1	Scope	The entire clause Testing has been substantially revised and published as Structural Testing to give better guidance on testing according to the Code of Practice Standards.
0 - Clause Removed	17.3	General Methods Of Testing Sheet Roof And Wall Cladding	The entire clause Testing has been substantially revised and published as Structural Testing to give better guidance on testing according to the Code of Practice Standards.
0 - Clause Removed	17.4	Commentary On 16.3	The entire clause Testing has been substantially revised and published as Structural Testing to give better guidance on testing according to the Code of Practice Standards.
0 - Clause Removed	17.5	Determining Wind load Span Graphs	The entire clause Testing has been substantially revised and published as Structural Testing to give better guidance on testing according to the Code of Practice Standards.
0 - Clause Removed	17.6	Specific Methods Of Testing Sheet Roof And Wall Cladding	The entire clause Testing has been substantially revised and published as Structural Testing to give better guidance on testing according to the Code of Practice Standards.
0 - Clause Removed	17.7	Wind and Point Load Testing	The entire clause Testing has been substantially revised and published as Structural Testing to give better guidance on testing according to the Code of Practice Standards.
0 - Clause Removed	17.8	Method: Resistance To Wind Pressures For New Zealand	The entire clause Testing has been substantially revised and published as Structural Testing to give better guidance on testing according to the Code of Practice Standards.
0 - Clause Removed	17.9	Background to wind load testing	The entire clause Testing has been substantially revised and published as Structural Testing to give better guidance on testing according to the Code of Practice Standards.
4 - Clause Inserted		17.1.5.3 Interpreting Point Load Results	New clause.
4 - Clause Inserted		17.1.3.2 Point Load Testing	New clause.
4 - Clause Inserted		17.1.1.1 UDL Load Testing Standard	New clause.
4 - Clause Inserted		9.4.2.7 Cricket Over-Flashing More Than 1 m Wide	New clause.
4 - Clause Inserted		9.4.3 Dormer Details	New clause.
4 - Clause Inserted		17.1.1.2 Point Load Testing Standard	New Clause.
1 - Minor Errata	14.2.2	14.2.2 Ordering	Punctuation fix.
3 - Substantial change to recommendation	13.1.3.1	13.4.2 Roof Edge Protection	Clause has been substantially revised in accordance with Worksafe: Working at Height in New Zealand.
3 - Substantial change to recommendation	13.1.3	13.4 Working At Height	Clause has been substantially revised in accordance with the HSWA 2015.
4 - Clause Inserted		9.4.2.6 Penetration Flashings on Trapezoidal Profiles	New clause, specifically showing penetration flashings on trapezoidal profiles.
3 - Substantial change to recommendation	14.19	14.20 Fixing Aluminium Sheeting	Section comprehensively revised to better reflect good trade practice and Manufacturer’s recommendations.
2 - Editing and rearrangement	3.15	3.4 Profiles	Inserted new Drawing: Profile Types
2 - Editing and rearrangement	3.15.2	3.4.2 Trapezoidal Profile	Removed drawing in favour of a more descriptive drawing: Profile Types.
4 - Clause Inserted	9.5.1	9.4.1 Penetration Back Flashings	Table removed.
4 - Clause Inserted		17.1.4 Test Report	New clause.
4 - Clause Inserted		17.1.5.2 Interpreting UDL Load Results	New clause.
4 - Clause Inserted		17.1.3.2 Point Load Testing	New clause.