Acceptable Solutions and Verification Methods For New Zealand Building Code Clause B1 Structure

B1 Structure Acceptable Solution B1/AS1 Second Edition  provides a compliance pathway for meeting the structural performance requirements of Clause B1 of the New Zealand Building Code, specifically for houses and small buildings. The scope of the document covers structural provisions for  houses and small buildings constructed with timber, steel, masonry, and earth, as well as individual elements such as stucco, drains, and glazing. It is suitable for use where good ground has been established. It references New Zealand and Australian standards for these features and includes modifications to the standards.  The second edition has been published in standalone format with improved clarity, consistent structure, and updated terminology. The acceptable solution references the Building Product Specifications. The second edition also includes minor amendments to correct formatting, grammar, and cross-references.

B1 Structure Acceptable Solution B1/AS3 Second Edition provides structural design guidance for small chimneys and hearth slabs associated with solid fuel-burning domestic appliances. It outlines acceptable construction methods for chimneys made of brick, concrete, or precast pumice concrete including specifications for materials, reinforcement, foundations, and seismic restraints. The document also details requirements for hearth slabs, including dimensions, reinforcement, and installation on timber or concrete floors. It includes bracing provisions for earthquake resistance. This edition has been published in a standalone format.

B1 Structure Verification Method B1/VM1 Second Edition provides a comprehensive framework for verifying compliance with Clause B1 of the New Zealand Building Code for the structural design of buildings. It references the AS/NZS 1170 suite for structural actions (including wind, snow, and earthquake loads) and outlines how to apply these standards with specific modifications. The document includes detailed provisions for materials such as concrete, steel, timber, aluminium, and earth, and addresses individual building elements like drains and windows. The second edition includes references to the Building Product Specifications and has to been published in a standalone form.

B1 Structure Verification Method B1/VM2 Second Edition is used for geotechnical design of foundations. This verification method outlines procedures for ultimate limit state design of shallow and pile foundations, including bearing and sliding resistance. The second edition includes references to the Building Product Specifications for timber piles and has to been published in a standalone form. The second edition has a revised layout, clearer structure, and updated definitions and references. It includes an appendix for site investigation and foundation settlement but these are informative only.

B1/VM1 is amended to reference NZS 3101:2006 Amendment 3. Allowance is made in B1/VM1 for the continued use of cast iron anchors and couplers until 1 November 2018.

B1/VM1 modifies the citation of NZS 3404:1997 to update design and construction requirements for steel structures.  Twelve Standards are referenced in B1/VM1 that provide these updated requirements. 

Duplicate provisions are deleted from B1/VM1 and errors are corrected in B1/VM4.

NZS 4223 Parts 1 to 4 are updated to the latest versions in B1/AS1, and the structural glass barrier requirements in Part 3 are modified.

Clause 7.4.1.3 and Figures 7.10(b) and 7.10(c) in NZS 3604 are modified to clarify the requirements (in accordance with the latest test data).

The modification in B1/VM1 on applying the hazard factor Z, to buildings with structure periods less than 1.5 seconds in the Canterbury earthquake region, is deleted.

The modification in B1/VM1 on applying a minimum risk factor for the serviceability limit state of R_s = 0.33 in the Canterbury earthquake region is deleted.

Clause 9.3.9.4.13 in NZS 3101 is modified in B1/VM1 to limit the depth of precast units to 300 mm and the overall depth to 400 mm.

The formula in B1/VM4 paragraph 3.3.2b) is corrected.

Cited content in this document can be found on the Building CodeHub website.

Amendment 14, 4 November 2016, to B1/VM1, B1/AS1.

Amendment 13, 1 June 2016 until 30 May 2017, to B1/AS1.

30 November 2016: Amendment 13 is confirmed in accordance with section 30 of the Building Act 2004. Amendment 13 was introduced on 1 June 2016 without prior public consultation, which subsequently occurred from 20 July to 31 August 2016. After considering feedback from this consultation, MBIE confirms Amendment 13 will continue in force. Reasons for this are:

• the potential for injury when structural glass barriers break unexpectedly 
• an increasing use of structural glass barriers.

Overview

All of the Acceptable Solutions and Verification Methods relating to B1 are contained in one document.

• B1/VM1 sets out general means for the design of structures to meet the performance requirements of B1 Structure. It includes modifications to the structural design actions Standards AS/NZS 1170 and the relevant materials Standards. 
• B1/AS1 references NZS 3604 Timber-framed buildings that if followed provides one way of demonstrating compliance with B1.  It gives information on designing for masonry, earth buildings, stucco, drains, and glazing. About NZS 3604 provides an overview of the Standard referenced in B1/AS1.
• B1/AS3 contains information on the structural requirements for small chimneys.
• B1/VM4 covers the limit state design of foundations, including those of earth retaining structures.
• Appendices A - C provide informative guidance on site investigation, determining foundation settlement and retaining wall foundations.

Amendment 11, 1 August 2011 until 14 August 2014, to B1/VM1, B1/AS1, B1/AS2.

Reprinted incorporating Amendment 9, 30 September 2010, to B1/VM1, B1/AS1, B1/AS2, B1/AS3, B1/VM4.

Reprinted incorporating Amendment 9, 30 September 2010, to B1/VM1, B1/AS1, B1/AS2, B1/AS3, B1/VM4.

B1 Structure – B1/AS1, B1/VM1, B1/AS3, B1/VM4, First edition, Amendment 9. 30 September 2010.