v25.09 September 2025
Important Revisions
Most of this revision consisted of editing and rearrangement for clarity, consistency, and accuracy.
- In Gutter Fall, we amended the MRM recommendation of a 1:200 fall for its effect on the aesthetics of the finished gutter. Although a fall of 5mm in 1m may improve self-cleaning and drainage, it may have an undesireable visual outcome.
- Our recommendations for making provision for expansion in aluminium were updated in both Roof Cladding Expansion Provisions and Recommendations for Fixing Aluminium to be less restrictive.
- Metal Cladding Testing was revised to improve understanding of testing requirements. These changes only affect how MRM members will publish testing results, not testing procedures.
- The entire clause Pressed Metal Tiles was revised and edited, with some information being updated.
- Warm Roofs were similarly revised and edited. Although there were no substantial changes to recommendations, the content was updated to reflect more modern techniques and approaches.
- The revision of Warm Roofs included updated details for Insulated Panels Barge Flashing.
Other Edits and revisions
The rest of this update is taken up with minor edits and revisions for clarity, grammar, and spelling.
Important Notice:
In a move to help us better understand our audience and make the NZMRM Metal and Wall Roof Cladding Code of Practice even more useful and relevant, we are introducing an industry selector to the existing registration form. If your particular industry is not listed please select one that is closest.
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Revision Detail v25.09 - 2025 - September
| Category | Clause Number (prior to update) | Clause (As of current publication) | Details |
|---|---|---|---|
| 3 - Substantial change to recommendation | 5.4.2.1 | Gutter Fall | Revision to clarify the acceptable and recommended amount of gutter fall. |
| 3 - Substantial change to recommendation | 7.3.2 | Roof Cladding Expansion Provisions | Revised Favourable Circumstances for Controlling Expansion to show the correct recommendations for aluminium. |
| 3 - Substantial change to recommendation | 14.19.2 | Recommendations for Fixing Aluminium | Changed the recommendation for sheet lengths over 10 m to 3 m. |
| 2 - Editing and rearrangement | 1 | Introduction | New revision message for v25.09, published on 1 September 2025. |
| 1 - Minor Errata | 4.6.3 | Material Selection | Clarification of C4 and C6 fasteners. |
| 1 - Minor Errata | 4.10.9 | Gutter Leaf Guard | Grammar and typo fixes. |
| 1 - Minor Errata | 4.15.1 | Ground Clearance | Typo fix. |
| 1 - Minor Errata | 5.4.7 | Gutter Capacity Calculator | Updated label of "Span length of roof" on Secret Gutter for clarity. This previously stated "Length of roof", which was ambiguous: calculations are unchanged. The enforced minimum remains unchanged at 2.2. |
| 2 - Editing and rearrangement | 5.6.2 | Sumps | Clarifying edit. |
| 2 - Editing and rearrangement | 5.7 | Downpipes | This clause was renamed, and some content was moved to Rainwater Heads, Sumps, and Overflows. Minor edit for clarity: removed the reference to astragalus. No other changes to content or recommendations. |
| 2 - Editing and rearrangement | 7.4 | End Laps | Removed historical error regarding the use of rivets. |
| 2 - Editing and rearrangement | 8.5.2 | Barge And Verge | Added illustrations showing details for |
| 1 - Minor Errata | 8.5.4 | Apron Flashings | Deleted "optional cation" statements. |
| 2 - Editing and rearrangement | 8.5.4.4 | Eaves Flashing | Updated and renamed Gutter-Eaves Flashing and introduced option 2. |
| 1 - Minor Errata | 10.10.1.2 | Fascia Vents | Typo fix. |
| 1 - Minor Errata | 10.10.2 | Battens | Typo fix. |
| 1 - Minor Errata | 10.11.1 | Underlay Standards | Aligned some table items. |
| 1 - Minor Errata | 10.11.6 | Installing Underlay | Typo Fix. |
| 1 - Minor Errata | 10.12.4 | The Mechanics of Condensation | Typo fix. |
| 1 - Minor Errata | 10.12.7 | Water Vapour Pressure | Typo fix. |
| 1 - Minor Errata | 11 | Natural Light | Typo fix. |
| 1 - Minor Errata | 11.1.1 | Compliance | Typo fix. |
| 1 - Minor Errata | 11.3.1 | Point Load on Translucent Sheets | Typo fix. |
| 2 - Editing and rearrangement | 11.4 | Thermal Resistance | Updated illustration: Double-Skinned Rooflight. |
| 1 - Minor Errata | 12.1.3 | Thermal Noise | Grammar fix. |
| 1 - Minor Errata | 12.2 | Purlin Creasing | Punctuation fix. |
| 1 - Minor Errata | 12.3 | Flashing Buckling | Punctuation fix. |
| 1 - Minor Errata | 12.4.3 | Installation | Some grammar fixes. |
| 1 - Minor Errata | 12.5.1 | Touch-Up | Grammar fix. |
| 1 - Minor Errata | 14.1 | Overhang | Minor layout edit. |
| 1 - Minor Errata | 14.1 | Pre-Installation | Typo fix. |
| 1 - Minor Errata | 14.5 | Walking On Roofs | Typo fix. |
| 1 - Minor Errata | 14.9 | Marking and Cutting | Typo Fix.
|
| 1 - Minor Errata | 14.12.1 | Nails | Punctuation fix. |
| 1 - Minor Errata | 14.12.2 | Screws | Punctuation fix and reformatted font in illustrations for consistency. |
| 1 - Minor Errata | 14.13.2 | Fastener Placement | Grammar fix. |
| 1 - Minor Errata | 14.18.1 | Roof Cladding Damage | Grammar fix. |
| 1 - Minor Errata | 14.18.3 | Correctly Installed Gutters | Typo fix. |
| 1 - Minor Errata | 14.18.4.1 | Preventing Swarf Damage | Formatting fix. |
| 1 - Minor Errata | 14.19 | Fixing Aluminium Sheeting | Punctuation fix. Added clarifying statement for using aluminium screws. |
| 1 - Minor Errata | 14.19.1 | Painted Aluminium | Typo fix. |
| 1 - Minor Errata | 15 | Other Products | Punctuation fix. |
| 1 - Minor Errata | 15.1 | Curved Roofs | Grammar fix. |
| 2 - Editing and rearrangement | 15.3.1 | Design | This clause was revised as part of a comprehensive revision of the parent clause, Pressed Metal Tiles. |
| 2 - Editing and rearrangement | 15.3.1.1 | Durability | This clause was comprehensively edited during a comprehensive revision of Pressed Metal Tiles.
|
| 4 - Clause Inserted | Structure | A new clause, created as part of a comprehensive revision of Pressed Metal Tiles | |
| 2 - Editing and rearrangement | 15.3.1.2 | Minimum Pitch | This clause was edited as part of a comprehensive revision of Pressed Metal Tiles. |
| 2 - Editing and rearrangement | 15.3.1.3 | Underlay | This clause was edited as part of a comprehensive revision of Pressed Metal Tiles. |
| 2 - Editing and rearrangement | 15.3.1.4 | Roof Framing | This clause was edited as part of a comprehensive revision of Pressed Metal Tiles. |
| 2 - Editing and rearrangement | 15.3.1.5 | Tiling Battens | This clause was edited during a comprehensive revision of Pressed Metal Tiles. We introduced a table for Batten Installation, replacing the multiple tables in Pullout resistance for different constructions (which was removed). |
| 0 - Clause Removed | 15.3.1.5 | Pullout resistance for different constructions | This clause was removed during an overall revision of Pressed Metal Tiles, and replaced with Batten Installation in Tiling Battens. |
| 2 - Editing and rearrangement | 15.3.2 | Valleys | This clause was edited as part of a comprehensive revision of Pressed Metal Tiles. |
| 4 - Clause Inserted | Installation | A newly created clause as part of a comprehensive revision of Pressed Metal Tiles. | |
| 2 - Editing and rearrangement | 15.3.3 | Roof Traffic | This clause was edited as part of a comprehensive revision of Pressed Metal Tiles. |
| 2 - Editing and rearrangement | 15.3.4 | Valley Installation | This clause was edited as part of a comprehensive revision of Pressed Metal Tiles. |
| 2 - Editing and rearrangement | 15.3.5 | Flashings | This clause was edited as part of a comprehensive revision of Pressed Metal Tiles. |
| 2 - Editing and rearrangement | 15.3.5.1 | Ridge | This clause was edited as part of a comprehensive revision of Pressed Metal Tiles. |
| 2 - Editing and rearrangement | 15.3.5.3 | Gable Ends | This clause was edited as part of a comprehensive revision of Pressed Metal Tiles. |
| 2 - Editing and rearrangement | 15.3.5.4 | Flashing Metal Tile to Wall | This clause was edited as part of a comprehensive revision of Pressed Metal Tiles. |
| 2 - Editing and rearrangement | 15.3.5.5 | Diverters | This clause was renamed and edited as part of a comprehensive revision of Pressed Metal Tiles. |
| 1 - Minor Errata | 15.3.5.6 | Penetrations | Typo fixes. |
| 2 - Editing and rearrangement | 15.3.6 | Longrun Tiles | This clause was edited as part of a comprehensive revision of Pressed Metal Tiles. |
| 1 - Minor Errata | 15.3.7 | Sitework | Fixed links. |
| 2 - Editing and rearrangement | 15.3.8 | Laying Metal Tiles | This clause was edited as part of a comprehensive revision of Pressed Metal Tiles. |
| 2 - Editing and rearrangement | 15.3.9 | Workmanship | This clause was edited as part of a comprehensive revision of Pressed Metal Tiles. |
| 1 - Minor Errata | 15.4.13.4 | Finishing at Ridges and Eaves of Tray Roofing | Typo fix. |
| 2 - Editing and rearrangement | 15.5.1.3 | Insulated Panel Face Profiles | Updated profile illustrations. |
| 1 - Minor Errata | 15.5.1.6 | Insulation Panel Insulation Values | Typo and grammar fix. |
| 2 - Editing and rearrangement | 15.5.1.18 | Insulated Panel Flashings | Replaced Insulated Panels Barge Flashing detail for accuracy. |
| 2 - Editing and rearrangement | 15.5.2 | Composite Systems | Editing for clarity. |
| 2 - Editing and rearrangement | 15.5.2.2 | Composite System Installation | Edited for clarity and accuracy. |
| 1 - Minor Errata | 16.1 | Maintenance Compliance | Typo fix. |
| 1 - Minor Errata | 16.6 | Special Maintenance | Typo fix. |
| 2 - Editing and rearrangement | 16.8.2 | Paint Application | Clause renamed for clarity. |
| 2 - Editing and rearrangement | 17.1.2 | Test Requirements | Edit for clarification. |
| 2 - Editing and rearrangement | 17.1.4 | Test Report | Edit for clarification. |
| 2 - Editing and rearrangement | 17.1.5.2 | Interpreting UDL Load Results | Edit for clarification. |
| 1 - Minor Errata | 17.1.5.3 | Interpreting Point Load Results | Typo fix. |
| 1 - Minor Errata | 17.2.3.1 | Site Testing | Typo fix. |
| 1 - Minor Errata | 17.2.5 | Weatherproofing | Typo fix. |
| 1 - Minor Errata | 17.3.1 | Soft Edge Product Technical Statement Requirements | Typo fix. |
| 1 - Minor Errata | 17.4.1 | Part1: AS/NZS 2728:2013 | Typo fix. |
| 1 - Minor Errata | 17.4.4 | Appendices of AS/NZS 2728:2013 included as Normative in the MRM Standard | Typo Fix |
| 1 - Minor Errata | 17.4.5 | Appendices of AS/NZS 2728:2013 considered Informative in the MRM Standard: | Typo fix. |
| 1 - Minor Errata | 18 | Useful Information | Typo fix. |
| 1 - Minor Errata | 18.1 | Conversion Factors | Text styling. |
| 1 - Minor Errata | 18.3 | Material Density, Melting Point, Expansion And Modulus | Typo fix. |
| 1 - Minor Errata | 18.4 | Decadic Number System | Typo fix. |
| 1 - Minor Errata | 18.8 | Sheet Metal Work For Roofing Contractors. | Typo fix. |
| 4 - Clause Inserted | v25.09 September 2025 | Revision details for the update on 1 September 2025. |
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