Sometimes what is approved needs to change because:

  • what works on paper doesn't work onsite, or
  • you may need to substitute a component or product for a similar one.

These changes can usually be managed through either:

  • a minor variation for small changes, or
  • an amendment to your building consent for more significant changes.

If you discuss a change onsite with an inspector, the inspection notice will state if an amendment or a minor variation is required.

If you're not sure what's needed, please contact us before making changes.

Make sure you discuss and get owner approval before you make any changes.

Substituting products during your build

During your build, you may decide to swap a specified product or component with a similar one. This could be due to cost, availability, or an owner request.

While substitutions may seem minor, they can have wide impacts, especially when part of a building system.

Why it matters

Even small changes can affect how a building performs – particularly for critical systems such as:

  • Structural bracing
  • Fire safety
  • Noise control.

Swapping small items like fasteners, sealants or adhesives can also affect how a system performs compared with what was approved in the building consent or required by the building code.

Responsibilities

Manufacturers and suppliers are responsible for product performance only when used as specified. They should provide documents showing compliance with the building code.

  • Relying on verbal assurances from suppliers can increase your risk.
  • if you choose to substitute a product, you are responsible for the outcome.

All substitutions should be approved by the building consent authority (BCA) as a minor variation or amendment.

This ensures:

  • The change is recorded on the consent file.
  • The substitution becomes part of the approved consent documentation.
  • You are better protected against future issues or claims.

What to do if you substitute a product

If you plan to make a substitution:

  • Confirm the product meets the same performance requirements as originally specified.
  • Check with the building consent authority that they will accept the change.
  • Confirm whether the change affects any existing warranties from the original manufacturer.

Manage your risk

To protect yourself:

  • Use the products and systems shown on the approved consented plans wherever possible.
  • Follow the manufacturer’s instruction – this helps ensure responsibility sits with the designer where appropriate.
  • For structural work, confirm there is clear evidence of building code compliance and that your proposed use is within scope.
  • If plans say product or equivalent, ensure alternatives:
    • Come from a reputable supplier or manufacturer.
    • Include warranties or guarantees.
    • Have independent 3rd party certification (eg CodeMark, BRANZ).
  • Keep your client informed in writing – provide them with copies of warranties and product information before work starts.

More guidance is available in MBIEs product substitution guidance document which provides practical advice for BCAs, designers, contractors and building owners.

Minor variation (small changes)

Where you make a small change that doesn’t significantly alter the approved plans and specifications or building code compliance.

Minor variations:

  • Are usually agreed and signed off by the inspector onsite.
  • Can only be applied for if before the code compliance certificate is issued.

As a general rule of thumb, a minor variation should not reduce compliance from what was originally approved.

Variations to the consent that are minor include (as per MBIE guidance):

  • Reducing scope of work.
  • Changing drainage plans.
  • Changing building location on the site.
  • Creating minor extensions of the same work – e.g. extending a deck or length of a retaining wall.
  • Adding clarifications to changing suppliers – e.g. swapping trusses from one supplier to another with the same layout.
  • Making minor changes to bracing design.
  • Aligning plans and specifications, correcting inconsistencies, adding minor details to plans that were inadvertently missed, and aligning a building consent with the resource consent.
  • Updating flashings.
  • Changing location of elements.
  • Changing people/consultants involved – e.g. the engineer listed on approved plan.

How to apply

Amendment (larger changes)

You’ll need an amendment where the relevant construction detail isn’t already included in the consented documents, new details are required, or compliance may be affected, e.g.

  • structure
  • internal and external moisture
  • onsite wastewater disposal
  • fire safety

Amendments:

  • Must clearly show what has changed with a cloud and a clear description of the change
  • Require updated supporting documents to allow the building control officer to be satisfied that the changes comply with the building code
  • Must be approved before work is carried out or covered up, and before the code compliance certificate is issued
  • May change the consent conditions and inspection requirements
  • Suspends your ability to book any inspections until the amendment is approved.

Amendments can take up to 20 working days to process, so allow for this time to avoid delays to your build.

Applying for an amendment

Apply online the same way as a building consent.

Make sure you include

  • a clear description of the change(s)
  • any change in the value of the building work
  • all relevant updated supporting documents, including updates to the design memorandum if required.

If you didn’t use the customer portal, you can

Amendments are charged based on processing time and extra inspections needed. The invoice must be paid before inspections can restart.