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


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.