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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 v25.03:Installation; Walking-Roofs

Walking On Roofs

14.5 Walking On Roofs 
It must not be assumed that it is safe or permissible to stand on any roof structure or roof cladding.
The manufacturer of the roof sheeting must provide technical literature stating the point load limitations of the profile. The information must indicate the positions on the sheet where persons may safely walk or stand without causing damage or, alternatively, indicate the necessity to provide temporary walkways.

For roofs tested in accordance with MRM testing standards see 17.1 Metal Cladding Testing, a Restricted Access roof will withstand a 100 kg point load applied to the rib or over two pans, and an Unrestricted Access roof will withstand a 100 kg point load to a single rib at mid span.  It must be taken into account that a worker laden with tools may weigh more than 100 kg, and impact loads can also contribute to exceeding this limit.

When access to the roof is necessary after construction, it is best practice to in the pan of the profile when walking up the roof, and follow purlin lines when traversing roofs.

14.5A Walking in the Pan

WalkingInThePan

Walking In The Pan

 

If ribs are too close together, so workers cannot place their feet in the pan, their weight must be spread evenly over at least two ribs when walking up the roof.

 

14.5B Spreading Weight over two Ribs

SpreadingWeightOverTwoRibs.

Spreading Weight Over Two Ribs.

 

Translucent sheeting must not be walked on unless it is designed specifically for that purpose.
 

 

 

 

Footwear

14.5.1 Footwear 
  • Anyone walking on the roof should wear flat rubber-soled footwear to prevent marking.
  • Put an old mat or piece of carpet at the base of the ladder so that shoes can be cleaned before going up on the roof, or dirty shoes should be removed and replaced at base of the ladder.
  • Smooth soled or open tread pattern shoes with good grip on smooth surfaces should be worn when working on a roof. Avoid the closely ribbed type which will carry swarf and other objects.