Minor variations clarified, not changed

The Ministry of Building, Innovation and Employment (MBIE) has told Under Construction that recent changes to minor variations definitions are intended to clarify, not change, what constitutes a ‘minor variation’

On 30 September 2024, new and amended building regulations came into effect. These include updates to clarify the definition of a ‘minor variation’ and create a definition of a ‘minor customisation’ for MultiProof approvals.

In response to questions from Under Construction, Sharon Threadwell, MBIE Acting Head of Building System Delivery and Assurance, said:

“Amended minor variation regulations seek to better clarify what level of discretion is available to Building Consent Authorities (BCAs) when it comes to small changes to the building design or specifications, after a building consent has been issued, that achieve an equivalent level of performance and do not affect Building Code compliance.

“A minor variation could include substituting a comparable product, like swapping out one brand of internal wall lining for a different brand of similar internal wall lining.

“BCAs will still need to assess proposed building work to ensure the building will comply with the Building Code but builders won’t need to make formal amendments to a building consent for minor, straightforward product or design changes.”

Guidance published

To provide further clarity, MBIE has published a Minor Variations Guidance document, which listed the following as examples of minor variations to building consents:

• Reducing scope of work.
• Changing building location on the site.
• Updating flashings.
• Creating minor extensions of the same work, such as extending a deck or length of a retaining wall.

The guidance also provides direction for builders on how to determine whether a change is a minor variation or not. It is a minor variation if:

1. The minor change achieves an equivalent level of performance to the original method.
2. The minor change isn’t likely to affect Building Code compliance of other parts of the building work.
3. The consequences of building failure because of the minor change wouldn’t be significantly worse from the original method.

Previously, MBIE has issued guidance for product substation due to uncertainty caused by shortages – such as the guidance issued for plasterboard in 2022. Now, the principles around how to evaluate building implications when assessing a minor variation have been codified in the amended Building (Minor Variations) Regulations 2009:

1. Whether the product substitution achieves an equivalent level of performance.
2. Whether the product substitution affects the compliance of other parts of the building work.
3. Whether the consequences of the building failing would be due to the product substitution.

The changes also apply to MultiProof designs, which will allow home builders to make minor variations to pre-approved designs without requiring further consents, said Building and Construction Minister Chris Penk.

“MultiProof designs […] are designs that have been pre-approved, meaning Building Consent Authorities must make a decision within 10 working days of receiving an application with a MultiProof design, rather than the usual 20 working days for a standard design.

“Now homebuilders will be able to make small customisations to these pre-approved designs without sacrificing the benefit of faster consenting and less red tape.”

MBIE also provided specific scenarios that could help builders determine whether a change is a minor variation or will require a consent amendment.

Below are some excepts from Minor Variations Guidance.

Scenario #1: minor variation for product substitution

The building inspector visits a new dwelling to inspect the roof installation. During the inspection, the building inspector identifies that although the specifications and drawings show profiled metal roofing, the owner wants to use pressed metal tiles instead. The roofer asks the building inspector to give approval to a minor variation on-site.

The building inspector considers this a minor variation because the product substitution of pressed metal tiles from profiled metal roofing achieves an equivalent level of performance with the Building Code; the product substitution isn’t likely to affect Building Code compliance of other parts of the building work; and the consequences of building failure isn’t significantly worse from using pressed metal tiles instead of profiled metal roofing.

The change is also well within the scope of the original building consent design. The building inspector approves the minor variation and records the proposed minor variation on the inspection notes and consent file, as well as dates and initials on the approved building consent plans. However, the building inspector informs the roofer that, upon completion of the work and before the issue of code compliance certificate, revised plans illustrating this change will be required. When back at the office, the building inspector also updates relevant consent records.

Scenario #4: formal amendment for product substitution

A plumber wishes to use an alternative aluminium piping system from overseas that they have read about on the internet, approaching a building official for a minor variation approval.

The official considers this not to be a minor variation because the new piping system is unfamiliar (it also doesn’t state the relevant information required by the building product information requirements) and falls outside the Acceptable Solution, requiring an alternative solution assessment.

They then advise the plumber that the consent applicant needs to apply for an amendment to the building consent, demonstrating how Building Code compliance would be achieved using this alternative product. The official records the conversation with the plumber in form of a file note on the consent file and updates relevant consent records.

Scenario #5: minor variation for load-bearing supports

During the construction of a new two-storey dwelling on a concrete slab, the owner proposes to enlarge a small window in the guest bedroom on the ground floor. The builder draws this to the attention of the building inspector during an on-site inspection; the builder is able to show the inspector that although the opening size will change, there will not be any point loads on the new lintel, and it still complies with NZS 3604 Timber framed buildings for the increased span, and any wall-bracing requirements will not be affected.

The building inspector accepts this as a minor variation, as it does not significantly deviate from the original design and will have a minimal effect on overall compliance with the structural stability requirements. The building inspector records the decision and the reasons for it on the inspection notes and makes a notation on the approved plans of what has been approved.

Note: It is important to ensure this approval is recorded on the consent file. This ensures that the file and council records are accurate; but it is also a legal requirement under the Building Act and the BCA accreditation regulations.

Scenario #8: formal amendment to change part of roof structure design

An owner wants to change part of the roof structure design from a trussed roof to a skillion roof using NZS 3604 rafters and seeks approval for a minor variation from the building inspector. This would not be considered a minor variation because of the significant departure from the approved building consent design, as it is a completely different structural system.

Other elements of the building could significantly be affected, such as insulation and bracing requirements. The building inspector advises the owner that the builder must not do any more work on the roof until an amendment to the building consent (including new plans detailing the construction change) has been applied for and the building consent authority has granted the amendment.

The building inspector then records the decision not to approve the minor variation on the inspection notes and updates relevant council records.