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Bulletins are summaries clarifying information in the NZMRM Metal Roof and Wall Cladding Code of Practice.

Available in PDF format, they can be used to support project documentation.

Bulletin BSCE01 Cut Edge Treatment

Submitted by Alex Taylor on Fri, 30/08/2024 - 3:49pm

Guidance to minimise cut edge corrosion.

Version 1, 29 February 2024

BSCE01-Cut_Edge_Treatment.pdf

Bulletin BV01 Cavity Batten Protection

Submitted by Alex Taylor on Fri, 30/08/2024 - 4:01pm

Department of Building and Housing advice on cavity battens.

Version 2, 25 February 2025

BV01 Cavity Batten Protection (V2.0).pdf

Bulletin BDL01 Double Lapping Roofing Sheets

Submitted by Alex Taylor on Fri, 30/08/2024 - 4:08pm

Clarifying when the use double lapping.

Version 1, 13 June 2024

BDL01_Double_Lapping_Roofing-Sheets.pdf

Bulletin BU01 Double Laying of Underlay on Re-Roof

Submitted by Alex Taylor on Fri, 30/08/2024 - 4:19pm

Recommendation for double laying underlaying when reroofing.

Version 1, 19 March 2024

BU01_Double_laying_of_Underlay_on_Re-Roof.pdf

Bulletin BC01 Clearance Between Sheet ends and Transverse Flashing

Submitted by Alex Taylor on Fri, 30/08/2024 - 4:24pm

Clarifying recommendation for clearance between the bottom of the sheet end and tranverse flashings.

Version 1, 23 April 2024

BC01_Clearance_Between_Sheet_Ends_and_Transverse Flashings.pdf

Bulletin PC01 Purlin Creasing or Print-through

Submitted by Alex Taylor on Mon, 09/09/2024 - 11:29am

Guidance regarding purlin creasing, print-through, and oil-canning.

Version 1, 27 February 2024

PC01_Purlin_Creasing_or_Print-through.pdf

Bulletin BPC01 Profiled Foam Closures

Submitted by Alex Taylor on Mon, 09/09/2024 - 11:34am

Clarifying situations when profiled foam closures are required.

Version 1, 23 April 2024

BPC01_Profiled_Foam_Closures.pdf

Bulletin BGLG01 Using Proprietary Leaf Guards

Submitted by Alex Taylor on Mon, 09/09/2024 - 11:37am

The MRM guidance for not using leaf guards.

Version 1, 29 February 2024

BGLG01_Using_Proprietary_Leaf_Guards.pdf

Bulletin BEL01 End Laps in Wall Cladding

Submitted by Alex Taylor on Mon, 09/09/2024 - 11:39am

Guidance regarding end laps in wall cladding.

Version 1, 14 August 2024

BEL01-End_Laps_in_Wall_Cladding.pdf

Bulletin BEF01 Position of Eaves Flashing to Underlay

Submitted by Alex Taylor on Mon, 09/09/2024 - 12:37pm

Eaves flashings are traditionally laid between the underlay and the eaves purlin. This is not always necessary, or even desirable.

Version 1, 26 March 2024

BEF01_Position_of_Eaves_Flashing_to_Underlay.pdf

BU02 Over-Saturation of Underlay

Submitted by marius@aptwrite.nz on Wed, 26/11/2025 - 11:12am

Advice and explanation for underlay failure.

11 November 2025, Version 1

bu02_oversaturation_of_underlay.pdf

 

BPD01 Wide Over-Flashings Behind Penetrations

Submitted by marius@aptwrite.nz on Wed, 26/11/2025 - 11:21am

Recommendation for designing wide Over-flashings behind penetrations.

6 October 2025, Version 1

bpd01_wide-over_flashings_behind_penetrations.pdf

BEMF01 Change of Pitch Flashings

Submitted by marius@aptwrite.nz on Wed, 26/11/2025 - 11:28am

Guidance on managing rust on change-of-pitch flashings.

28 October 2025, Version 1

bemf01_change_of_pitch_flashing.pdf

BI01 The Importance of Maintenance of Metal Roofing and Walling

Submitted by marius@aptwrite.nz on Wed, 26/11/2025 - 11:39am

Regular cleaning and annual inspections are essential to improve the durability and performance of metal roof and wall cladding.

31 May 2024, Version 1

bi01_the_importance_of_maintenance.pdf

BWLS01 End Spans of Roofing Sheets

Submitted by marius@aptwrite.nz on Wed, 26/11/2025 - 11:45am

Using the load/span fixing patterns in E2/AS1, where reduced end spans are not applied, will still comply with the performance requirements of NZBC B1-Structure.

17 October 2025, Version 1

bwls01_end_spans_of_roofing_sheets.pdf

BSP01 Replacing Secret Fixed Trough Section at a 1° Pitch

Submitted by marius@aptwrite.nz on Wed, 18/06/2025 - 3:19pm

Roof replacement with a “like with like” does not require a building consent (Exemptions Guidance for Schedule 1 of the Building Act 2004, Fifth edition August 2020).

Version 2, 4 March 2024

Re-Roofing at 1 Degree.pdf

Bulletin BA01 Required Temper for Aluminium Cladding

Submitted by marius@aptwrite.nz on Thu, 29/05/2025 - 12:01pm

The temper and the alloy affect the tensile strength of aluminium cladding, which affects both point load and distributed load performance.

Version 1, 11 February 2025

 

BA01-Required_Temper_for_Aluminium_Cladding.pdf

Bulletin BGC01 Pre-painted Metal Wall-Ground Clearance

Submitted by marius@aptwrite.nz on Thu, 29/05/2025 - 11:44am

Durability, rather than weatherproofness, motivates metal wall-to-ground clearances. Clearances are designed to prevent the build-up of vegetation or debris, which can be corrosive.

Version 1, 29 February 2025

BGC01_Ground_Clearance.pdf

Bulletin BCVW01 Support Spacings on Vertical Wall Cladding

Submitted by marius@aptwrite.nz on Wed, 28/05/2025 - 3:50pm

The Code of Practice (COP) can be used to support designs for vertical corrugated cladding at spans greater than 480 mm. 

Version 1, 7 May 2024..

BCVW01 Support Spacings on Corrugate Wall Cladding.pdf

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