v25.03 March 2025
The updates published on 1 March 2025 mostly include some changes to recommendations and some editing and rearrangement for clarity and consistency.
Important Changes
We replaced the illustration for Ridge-Hip Junction as experience showed the extra line of defence previously shown is not required.
A new clarifying statement in Cricket Over-Flashing More Than 1 m Wide gives guidance on when to use this detail rather than some of the under-soaker variants.
We changed Underlay Durability to recommend specifying material strictly in accordance with the manufacturer’s recommendations when using synthetic underlay in unlined situations where it is exposed to fumes or reflected UV.
We've raised the Gutter Capacity Calculator default Short-Term Intensity Multiplication Factor for Commercial Internal Gutters to 3.1 (from 2.2) for a more cautious design, while the minimum remains 2.2. This factor adjusts 10-minute rainfall figures for higher short-term intensities. Non-residential roofs now match the 3.1 default but can be adjusted down to 2.2 if needed.
Other Notable Revisions
We edited Steel Cladding Wind Load Span Graphs and Wind Load/Span Graphs – Designs to AS/NZS1170 to remove identical content in these two clauses. There were no changes to recommendations and no information was deleted. A new sub-clause gives guidance on Fastener Pull-out in SED situations.
The Glossary now has added definitions for dunnage, straps, and strops.
For Internal Moisture Compliance, we added an improved explanation of the compliance requirements of NZBC E3.3a. We similarly introduced improved guidance to Stopends to aid clarity, with no changes to recommendations.
In another bid to improve clarity, we replaced 'C1" and "C2" designations in Minimum Flashing Cover with "X" and "Y" labels to reduce confusion.
In the Compatibility Table, we revised the terminology for ZM Coated Steel to ZM/AM Coated Steel and moved Pre-Painted ZM/AM Coated Steel to be directly after ZM/AM Coated Steel to make the table more accurate and more easily interpreted.
The rest of the updates and revisions consisted of minor edits for clarity, grammar, and spelling. There were no other changes to recommendations.
Revision Detail v25.03 - 2025 - March
| Category | Clause Number (prior to update) | Clause (As of current publication) | Details |
|---|---|---|---|
| 2 - Editing and rearrangement | 1 | Introduction | New revision message for v25.03, published on 1 March 2025. |
| 2 - Editing and rearrangement | 2.1 | Definitions | Added definition for dunnage, straps, and strops. |
| 2 - Editing and rearrangement | 3.11 | Wind Load/Span Graphs – Designs to AS/NZS1170 | Revision of the introduction to remove repeated content. The rest of the content is still available in Steel Cladding Wind Load Span Graphs. |
| 2 - Editing and rearrangement | 3.11.1 | Steel Cladding Wind Load Span Graphs | Editing to address repeated content. The removed content is is still available in Wind Load/Span Graphs – Designs to AS/NZS1170. |
| 4 - Clause Inserted | Fastener Pull-out | A new clause is giving guidance on fastener pullout in SED situations. | |
| 3 - Substantial change to recommendation | 4.9.4 | Compatibility Table | Revised ZM Coated Steel to ZM/AM Coated Steel and changed Pre-Painted Steel to Pre-Painted ZM/AM Coated Steel; moved Pre-Painted ZM/AM Coated Steel to be directly after ZM/AM Coated Steel. |
| 3 - Substantial change to recommendation | 5.4.7 | Gutter Capacity Calculator | Update the default Short-Term Intensity Multiplication Factor for Commercial Internal Gutters to 3.1 (from 2.2) as recommended for more prudent design. The enforced minimum remains unchanged at 2.2. |
| 1 - Minor Errata | 5.5.1 | Valley Fixing | Typo fix. No changes to recommendations. |
| 2 - Editing and rearrangement | 8.4 | Flashing Cover | Replaced 'C' and 'D' with 'X' and 'Y' to improve useability and extract Minimum Flashing Cover to a more visible level. |
| 3 - Substantial change to recommendation | 8.5.1 | Ridge and Hip Intersections | Replaced illustration for Ridge-Hip Junction as experience showed the extra line of defense is not required in these situations. |
| 3 - Substantial change to recommendation | 9.4.2.7 | Cricket Over-Flashing More Than 1 m Wide | Added clarifying statement for use case of this detail, rather than other Undersoaker variants. |
| 2 - Editing and rearrangement | 10.1.4 | Compliance | We added a more detailed explanation of NZBC, clause E3.3a requirements for compliance. |
| 3 - Substantial change to recommendation | 10.11.5 | Underlay Durability | Clause revised and expanded. |
| 2 - Editing and rearrangement | 14.16 | Stop-ends | Improved guidance for stop-ending cladding. No changes to recommendations. |
| 1 - Minor Errata | 15.5.1.6 | Insulation Panel Insulation Values | Deleted an editorial comment, that was accidentally published. No changes to recommendations. |
| 4 - Clause Inserted | V25.03 March 2025 | Revision details for the 1 March 2025 update. |
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