Off-site construction

Last updated: 2 March 2018

If your building work includes any components constructed off-site, you will need the manufacturer or supplier to provide clear evidence of how their product meets Building Code requirements, as well as providing assembly and installation instructions.

Off-site construction refers to building components or buildings made off-site (away from the final building site). This work can range in size and complexity, and include:

  • smaller components, such as window assemblies
  • complex components, such as whole wall panels, modules and complete buildings.

Components or buildings can be fully assembled off-site or can require on-site assembly (for example, kitset or flat packs).

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Application for building consent – demonstrating compliance with the Building Code

You will need to submit evidence of compliance with your building consent application. Your building consent application should include both the on-site building work and any off-site building work.

This consent is usually best granted by the council or building consent authority (BCA) in the area where the final building site is located. This consent should include any components that have been constructed off-site (including offshore).

Product assurance

Manufacturers or suppliers may be able to demonstrate Building Code compliance by:

  • providing good technical evidence about their building components (for example, using a product technical statement)
  • membership of relevant industry schemes (for example, the Window Association of New Zealand, WANZ)
  • independent testing and assessments
  • appraisals
  • product certification. 

MBIE’s product assurance decision tool can help you choose the most suitable and cost-effective way to show your product meets Building Code requirements.

Product assurance decision tool

MBIE recommends discussing how compliance with the New Zealand Code will be demonstrated with both the product manufacturer and the BCA prior to applying for a building consent. The council will need to decide, in its capacity as a BCA, whether the evidence is sufficient on reasonable grounds. The council will generally consider factors such as the building components:

  • size and complexity
  • contribution to critical aspects of building performance (for example, structure or weathertightness)
  • previous use (commonly used or innovative)

The manufacturer should also be informed if the council will be undertaking an inspection during construction.

Product assurance and MultiProof has more information about product assurance options.

Obtaining a code compliance certificate – compliance with the building consent

In order to obtain a code compliance certificate you will need to be able to demonstrate that the building work complied with the building consent. It is important that you discuss this requirement with the council and manufacturer prior to obtaining a consent to ensure that you are able to demonstrate that the building work complies with the building consent.

Councils (or BCAs) carry out inspections during building work so they can be satisfied on reasonable grounds that the building work complies with the consent. Council inspections are usually at key stages of building work. For example, these may be before installing wall lining or cladding to check that the insulation and structural framing matches the consent requirements.

The Building Act does not specify the number or type of inspections required while building work is underway. While councils generally set their own inspection schedules, building consent applicants can propose alternatives in the consent application based on their own degree of supervision and quality control.

When proposing an inspection schedule the applicant needs to make sure the council can follow this schedule and still be satisfied that the building work complies with the consent. It is a condition of every building consent that the council can inspect work completed on-site and off-site.

Sometimes construction will take place in a different region to where the applicant is applying for consent (ie the area where the final building is located). In this situation councils may undertake inspections through a third party or by engaging council officers from the region where the construction is taking place.

It is important that applicants engage with their council early on in the process to determine the best process for ensuring compliance with the building consent.

Where construction occurs offshore it is unlikely that an inspection will be possible. Quality assurance measures become particularly important in providing reasonable grounds to satisfy a council that the building work complies with the New Zealand Building Code. Early engagement with the council is essential in this situation.

Quality assurance

Quality assurance measures may go some way to demonstrating that the off-site construction has been completed in accordance with the building consent. 

Quality assurance process details could include:

  • factory processes
  • manufacturing controls
  • details of any installation or assembly requirements
  • controls to ensure Building Code compliance when incorporated into a particular building project
  • details of any transportation requirements or pre-installation protocols (to minimise the risk of damage in transit or of substandard components being accepted at the building site)
  • any independent or self-certification of the factory.

Completing the installation

The council must approve and document any substitutions or changes made during construction.

Once the installation is complete, the manufacturer needs to give the building owner and the council any further evidence of compliance with the building consent. This might include a statement from the manufacturer or maintenance information. The council may need this for its final sign-off (code compliance certificate) of the overall project. The building owner may also need it to protect warranties, by meeting maintenance requirements.

Build to the consent includes information about the building process through to sign-off.

This information is published by the Ministry of Business, Innovation and Employment’s Chief Executive. It is a general guide only and, if used, does not relieve any person of the obligation to consider any matter to which the information relates according to the circumstances of the particular case. Expert advice may be required in specific circumstances. Where this information relates to assisting people: