2025 Building Code update

The first version of the Building Product Specifications

MBIE has published the first version of the Building Product Specifications, effective 28 July 2025.

The Building Product Specifications contains building product standards and specifications in relation to their manufacture, fabrication, testing, quality control, physical properties, performance, installation, and/or maintenance.

As a consequence of publishing the Building Product Specifications, multiple acceptable solutions and verification methods have been revised to cite the Building Product Specifications. Many of these documents have been published as new editions with a modern look.

The Building Product Specifications cannot be used on its own to demonstrate compliance with any requirement of the Building Code. To comply with the relevant acceptable solutions or verification methods that cite the Building Product Specifications, building products conforming to the Building Product Specifications must be used with the scope, limitations, and other applicable requirements set out in the relevant acceptable solutions and verification methods.

New acceptable solutions and verification methods

Further details on the new acceptable solutions and verification methods are listed on this page. This includes information on:

• where the Building Product Specifications have been incorporated into the relevant acceptable solutions and verification methods
• other minor amendments to the document that do not affect the level of performance required in the document but may assist in the interpretation of the requirements. This includes corrections for typos, grammar, cross-references, punctuation, formatting, headings, paragraphs, and definitions.

The new editions now have a consistent structure for the headings, paragraphs, figures, tables and should be easier to use in an electronic format. To help you familiarise yourself with the new documents, each document has a summary upfront that states the main changes in each version. For longer documents, we have also provided information sheets including lists of where the headings and paragraph numbers may have changed.

While the document may look different, it is important to remember that the revisions to the acceptable solutions and verification methods do not require anything new to be undertaken to comply with the Building Code. However, the documents are intended to be easier to read, easier to understand, and provide more options for building products to comply with.

Consultation on the Building Product Specifications

The publication of the Building Product Specifications was made following a consultation on the standards and other material proposed to be incorporated into the Building Product Specifications.

In this consultation, MBIE received widespread support for the intent of the Building Product Specifications, to enable greater use of overseas building products within existing Building Code compliance pathways. MBIE heard from submitters on the importance of being clear about the scope and limitations of the Building Product Specifications content and the value of citing up-to-date versions of standards.

Following consultation, MBIE made minor changes as a result of feedback on the timber and steel standards. This included removing the proposed reference to some older product standards and adding references to more recent versions of others.

On 9 and 10 June 2025, MBIE hosted two webinars to discuss the Building Code Update and answer questions.

View a recording of the webinar - youtube.com

View the slides from the webinar [PPTX 9.1MB]

B1 Structure

B1/AS1, B1/AS3, B1/VM1 and B1/VM2 (previously B1/VM4) have been published as new editions as standalone documents with the following titles:

• Acceptable Solution B1/AS1 Structural provisions for buildings, Second edition
• Acceptable Solution B1/AS3 Small chimneys, Second edition
• Verification Method B1/VM1 Structural design of buildings, Second edition
• Verification Method B1/VM2 Geotechnical design of foundations, Second edition.

B1/AS1 refers to the Building Product Specifications for welded steel mesh, timber framed wall bracing, timber piles, and glazing. 

B1/AS3 refers to the Building Product Specifications for pumice concrete units, reinforcing steel, hot dip galvanising, zinc coating of restraint components and in the definition of non-combustible materials. 

B1/VM1 refers to the Building Product Specifications for structural steel and steel fasteners, windows, and compaction testing. 

B1/VM2 refers to the Building Product Specifications for timber piles. The previous version of this document was published as B1/VM4 Foundations. 

These documents have all been issued in a new layout and include amendments to correct typos, grammar, cross-references and punctuation.

To help familiarise yourself with the new documents and where headings or paragraphs have changed, we have provided additional information sheets for each acceptable solution and verification method including a side-by-side list of the changes to heading numbers and paragraphs.

B2 Durability

B2/AS1 and B2/VM1 have been published as new editions as standalone documents with the following titles:

• Acceptable Solution B2/AS1 Durability provisions for building elements, Third edition
• Verification Method B2/VM1 Durability of buildings elements using in-service history, laboratory testing, and comparisons to similar materials, Third edition.

B2/AS1 now refers to the Building Product Specifications for timber treatment and some content from the previous edition has now been relocated to the Building Product Specifications. The information sheet for B2/AS1 identifies the specific content that has been relocated along with a side-by-side list of the changes to heading numbers and paragraphs.

B2/VM1 has had minor amendments to correct wording to fit in the new layout of the documents. No other changes were made to B2/VM1 except for these minor updates.

C Protection from fire

C/AS1, C/AS2, and C/VM2 have been published as new versions to reference the Building Product Specifications for fire testing. Each of these documents previously contained multiple pages of appendices which have now all been included into the Building Product Specifications as a central resource for all fire testing requirements.

C/AS2 and C/VM2 have also been published as new editions. For C/AS2, headings and paragraphs have been consolidated in Parts 3 and 4 to streamline the content.

C/VM2 includes several changes to the headings and layout of the document. It was previously published with limited use of paragraph numbering, which made referencing and navigating the requirements more difficult than it needed to be. This has changed with paragraphs added through the document. Other pieces of repeated text in the document have been simplified and revised to use wording consistent with the defined terms and requirements.

To help familiarise yourself with the new documents and where headings or paragraphs have changed, we have provided additional information sheets for the three documents including a side-by-side list of the changes to heading numbers and paragraphs.

E2 External moisture

E2/AS1, E2/AS2, E2/AS3, and E2/VM1 have been published as new editions as standalone documents with the following titles:

• Acceptable Solution E2/AS1 External moisture provisions for timber-framed buildings up to 10 m in height, Fourth edition
• Acceptable Solution E2/AS2 External moisture provisions for earth buildings, Fourth edition
• Acceptable Solution E2/AS3 External moisture provisions for concrete and concrete masonry buildings, Fourth edition
• Verification Method E2/VM1 Cladding systems of buildings up to 10 m in height – including junctions with windows, doors and other penetrations, Fourth edition.

E2/AS1 and E2/VM1 have been amended to reference the Building Product Specifications. They have also had minor amendments to correct wording to fit within the new document layout. The main layout and organisation of E2/AS1 and E2/VM1 remain unchanged. However, some of the sections and paragraph numbers have shifted.

To help familiarise yourself with the new documents and where headings or paragraphs have changed, we have provided additional information sheets for the two documents including a side-by-side list of the changes to heading numbers and paragraph.

E2/AS2 and E2/AS3 have had minor amendments to correct wording to fit in the new layout for the documents. No other changes were made to E2/AS2 and E2/AS3 except for these minor updates.

G4 Ventilation

G4/AS1 and G4/VM1 have been published as new editions as standalone documents with new titles:

• Acceptable Solution G4/AS1 Ventilation of buildings Fifth Edition
• Verification Method G4/VM1 Ventilation rate and air purity Fifth Edition.

G4/AS1 now refers to the Building Product Specifications for air handling systems in Paragraph 2.3.1.1. These documents have also been amended to correct typos, grammar, cross-references and punctuation. Table and figure notes, headings, paragraphs and definitions have been re-written to enhance clarity. No other changes were made to G4/VM1 except for these minor updates.

Some sections of G4/AS1 have been re-organised into a different order. We have provided additional information on the document and a side-by-side list of the changes to heading numbers and paragraphs.

H1 Energy efficiency

Verification Method H1/VM3 has been amended to reference the Building Product Specifications for determining the motor efficiency of pumps used in an air conditioning system in Paragraph 6.2.1.1. Other minor amendments have been made to the document to correct typos, grammar, cross-references, punctuation, and formatting of the document.

Next steps for other acceptable solutions and verification methods for energy efficiency

On 3 July 2025, MBIE announced part of the outcome of consultation on Acceptable Solutions H1/AS1 and H1/AS2 and Verification Methods H1/VM1 and H1/VM2.

The two acceptable solutions currently include the Schedule Method that shows exactly how much insulation must be used in different parts of the country to meet Building Code requirements for new buildings. This one-size-fits-all approach can be more expensive than other ways of complying with the Building Code.

Following consultation earlier this year, the Schedule Method will be removed from H1/AS1 and H1/AS2 by the end of 2025 and designers will have a transition time of 12 months to adjust to the changes.

Announcements about other simple changes to the H1 insulation requirements in the acceptable solutions and verification methods will be made closer to the time.

This will follow with publications of new editions of H1/AS1, H1/AS2, H1/VM1, and H1/VM2. These new editions will also be revised to include reference to the Building Product Specifications for insulation. This section has already been included and published in section 4.5 in the first version of the Building Product Specifications.

Transition period

Previous versions of the acceptable solutions and verification methods can continue to be used for 12 months until 31 July 2026.

After this date, the previous versions can no longer be used to demonstrate compliance with the Building Code.