Alterations to Existing Buildings

What is an alteration to a building?

Changes made to an existing building, such as (but not limited to) increasing or decreasing the floor area, making or closing an opening, erecting or demolishing a wall etc

Applying for consent for an alteration to an existing building

The building consent can only be granted where the building consent authority/territorial authority is satisfied that the building will:

  • comply as nearly as is reasonably practicable with the Building Code provisions for means of escape from fire and access and facilities for people with disabilities (if required)
  • continue to comply with the other provisions of the Building Code to at least the same extent as before the alteration.

Building consent authorities are allowed to grant a building consent for the alteration of an existing building.

The Act clarifies that if part of a building is altered, the upgrade provisions are triggered for the whole building.

For more information, please refer to publications on the MBIE website and Section 112 of the Building Act 2004.


Converting a building fact sheet

BC application - dwellings and other work (NOT Commercial) (pdf, 1.3MB)

Earthquake Prone Buildings

For more information regarding alterations to Earthquake prone buildings please refer to the Earthquake Prone Buildings section.