Alterations and Change of Use

Change the use of a building

The building Act requires that if a building owner intends to change the use of a building or extend the life of a building beyond its specified life the Council must be notified in writing before any work commences. 

The Council needs to check that the new building work or use of the building complies with the Building Code as far as reasonably possible in the areas that are being altered. A change in use may require upgrading of safety features, accessibility and disabled facilities within the existing building, as different provisions exist for different types of buildings and uses.

The extent of upgrading required depends on the building proposal or use. Building code requirements differ from one type of use to another – for example, for a residential villa which becomes a restaurant, a warehouse which becomes an apartment, or a garage which becomes a studio and sleep-out.

In all cases, the entire building must continue to comply with the building code to the extent that it did before the alteration or change of use.

For some alterations essential sanitary upgrading is needed for protection from other property:

  • fire egress and escape from buildings

  • access and facilities for people with disabilities

  • Earthquake assessment by structural engineer in accordance with RLC Earthquake Prone Building Policy.

Alterations to existing buildings

For some change of use proposals, upgrading is also needed for:

  • protection of other property 

  • sanitary facilities 

  • structural and fire-rating aspects

  • Earthquake assessment by structural engineer in accordance with RLC Earthquake Prone

Building Policy

These essential requirements must be upgraded to a standard "as nearly as is reasonably practicable" the same as that required for a new building.

If you are an owner planning changes to your building, discuss your plans with Council early in the project, to avoid delays with building consent.

Council will most likely advise you to get the whole building assessed for any change of use or part thereof as this may have an effect on the whole or other parts of the building. It is therefore advisable to have the whole building assessed by a suitably qualified fire engineer who should cover all the building code clauses and make recommendations as to what changes will be required in order to make the building comply "as nearly as reasonably practicable" the same as that required for a new building.

For more information see Change of Use Guidance information and  Change of Use Factsheet

For changes of use for residential buildings changing a Non Habitable Building (e.g. garage) to a Habitable

If the change of use includes a new household unit where one did not exist before then the building must comply with all aspects of  the Building Code as near as reasonably practicable.

The following information must be provided to demonstrate compliance with the building code.

  1. Certify that there is a damp proof membrane under the slab or use of a suitable water proof topping to be specified.
  2. Finished floor level in relation to ground (requires 225mm to natural ground or 150mm to a paved surface).
  3. Insulation to both walls (including joinery) and roof space.
  4. Appropriate underlay to both roof and wall cladding.
  5. Structural considerations:
    1. Trusses at max 1200mm centres
    2. Bracing to walls (calculated as if there is no existing bracing. Windows and door openings to comply with E2AS1 as near as reasonably practicable (e.g. air seals and flashings etc)
  6. Warning systems and any other building code clauses that may be affected as a result of the proposed change

N.B. proprietary garages are usually constructed to NZS 4203 where habitable buildings are constructed to NZS 3604. 

Page reviewed: 03 Jul 2019 10:11am