The November 2019 improvements to the Building Code provide safer solutions for building houses, increase construction options and respond to feedback we’ve received from the sector.
The finalised changes start to come into effect from 28 November 2019, with individual transition times detailed below.
Changes are being made to support safer and more resilient housing foundations for buildings on liquefaction-prone ground. These changes will:
- Reduce the likelihood of massive failures of foundations of structures where known liquefaction and lateral spread hazards exist across the country.
- Require specifically designed foundations for buildings on ground that has been identified as prone to liquefaction.
- Ensure new homes are built safely and strongly enough to withstand liquefaction risks.
- Provide clarity to territorial authorities (TAs), building consent authorities (BCAs) and engineers when designing for liquefaction-prone ground.
These regulations are already in place in the Canterbury region, and will now be extended to all of New Zealand.
Specifically, the changes include:
- Limiting the application of the B1 Acceptable Solution B1/AS1 so that it may not be used on ground prone to liquefaction or lateral spreading.
- Limiting the application of B1/AS1 Foundation Design buildings that are on ‘good ground’ that is not prone to liquefaction or lateral spread. This is currently the case in Canterbury.
- Amending Acceptable Solution B1/AS1 to include the information on the design of foundations in expansive soils that was previously contained in the Simple House Acceptable Solution, and revoking SH/AS1.
The current Building Code solutions to ‘good ground’ in B1/AS1 will continue to comply until 28 November 2021. This change requires councils and territorial authorities to complete liquefaction mapping within the two years.
Shifting certain information from SH/AS1 to B1/AS1 and revoking SH/AS1
B1/AS1 is amended to include the information on the design of foundations in expansive soils that was previously contained in the Simple House Acceptable Solution (SH/AS1).
The advantages of retaining the expansive soil foundation details are that:
- current knowledge and practices for the design of house foundations on expansive soils will be included in an Acceptable Solution
- maintaining the information in an Acceptable Solution will help consenting efficiency in areas with expansive soils.
Upon publishing the amended B1/AS1, SH/AS1 will be revoked.
National Association of Steel Framed Housing (NASH)
We are making the National Association of Steel Framed Housing (NASH) standard an Acceptable Solution, rather than an Alternative Solution. This change will help improve consenting efficiency for steel-framed housing by offering more choice for designers and architects.
This change will also give developers and designers more construction material options, which in turn supports high-density housing and the construction market overall.
The current Building Code solutions will continue to comply for building consent applications lodged until 28 February 2020. If the existing methods are used after these dates, they must be considered as an Alternative Solution proposal.
MBIE is supporting energy efficient lighting in H1/AS1 by referencing an amended version of the Standard used to assess lighting efficiency in large buildings.
Other changes continue the maintenance of the Building Code documents with updated references, cited Standards and corrected editorial errors. These include:
References section changes to B1/AS1
- Add Amends for AS/NZS 2566:2002
- Change AS 1397:2001 to AS 1397:2011
- Add Amend: 1 for AS/NZS 4600:2005
- Add Amend: 1 for AS/NZS 1163:2016.
Definition section changes to B1/AS1
- Change the definition of ‘good ground’.
Content changes to B1/AS1
- Addition of ‘and Amendment 1’ to 6.1 AS/NZS 2566.1
- Addition of ‘and Amendment 1, 2 and 3.’ to 6.2 AS/NZS 2566.2
- Comment change in B1/AS1
- Remove ‘– for the Canterbury earthquake region only)”’ from 3.1.1 NZS 3604
- Remove ‘in the Canterbury earthquake region only’ from 3.1.14 NZS 3604
- Correctly cite AS3 in 1.2 B1/AS
- Remove ‘in the Canterbury earthquake region only’ from 2.1.2 NZS 4229
- Remove ‘– for the Canterbury earthquake region only)”’ from 4.1.1 NZS 4299, Paragraph 1.3 Definitions
- Remove ‘in the Canterbury earthquake region only’ from 4.1.5 NZS 4299.
Addition of new clause to Section 3.0 Timber – B1/AS1
- Include the information on the design of foundations in expansive soils (previously contained in the Simple House Acceptable Solution). Relevant content pertaining to expansive soils is moved to Paragraph 3.2 of B1/AS1.
Content changes to B1/VM1
- Update the name of the Standard to ‘“AS 1163 Cold-formed structural steel hollow sections”.’
Content changes to B2/AS1
- Cite the correct clause from ‘44 of the Building Act.’ to ‘section 100 of the Building Act.’
Reference section changes to H1/AS1
- Change section ‘3.3 or 3.4.’ to ‘section 3.3.’ in VM1 1.3.1 Comment 1
- Add Amend: 1 to References
- Remove ‘or section 3.4’ from 6.1.1
- Update References section page for NZS 4218:2009 Thermal Insulation – Housing and Small Buildings
- Update References section page for NZS 4214:2006 Methods of determining the total thermal resistance of parts of buildings.
Content changes to H1/AS1
- Correction of spelling error in H1/AS1, Verification Method section 1.1
- Correction of spelling error in H1/AS1, Accepted Solution section 2.1 comment
- Correction of spelling error in H1/AS1, Accepted Solution section 2.1.4 comment
- Correction of spelling error in H1/AS1, Accepted Solution section 2.1 comment.