The Building Act 2004 requires that if a building owner intends to change the use of a building or extend the life of the 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 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 disability facilities within the existing buildings, as different provisions exist for different types of buildings.
Notification of Change of Use form
Approval to Proceed with Building Work
Approval will depend on the Building Code requirements for the use intended and will differ from one type of use to another. You may need to provide additional information to assist Council in deciding if it will comply in its new use, or if a Building Consent will be required. 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.
If you are thinking about alterations/building works that will change the use of an existing building you should talk to your local Council to see if a Building Consent (and/or Resource Consent) is required, or what is needed to comply with building provisions. This should be done at an early stage to avoid any delays.
Examples of change of use
- Conversion of a garage/basement into a bedroom (a non-habitable building to a habitable building)
- Conversion of a dress shop into a paint shop (change to a high risk occupancy)
- Conversion of a home into a café (a residential dwelling converted into a public place or operation of a business from home - access and facilities need to be considered here)
- Changing occupant load of a commercial building from 49 to 51 or more people (requires a change to fire alarm requirement).
A change of use is not:
- Changing from a higher risk commercial occupancy to a lower risk one (no increase in fire safety systems required)
- Converting a dwelling into storage (no increase in fire safety systems required)
- Converting a retail outlet to a warehouse (where there is no increase of fire safety systems required)
Example: Changing a Garage or Basement into a Bedroom
This is an example where you are changing a garage or basement (non-habitable building) into a bedroom (habitable building). 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 nearly as is reasonably practicable. The following information must be provided to demonstrate compliance with the Building Code.
- Certify that there is a damp proof membrane under the slab or use of a suitable waterproof topping on the slab.
- Finished floor level in relation to ground (requires 225mm to natural ground or 150mm to a paved surface), or adequate waterproofing membrane to walls.
Insulation of walls (including joinery) and roof space to meet Building Code requirements.
- Appropriate underlay to both roof and wall cladding.
- Structural considerations:
- Bracing to walls (calculated as if there is no existing bracing).
- Trusses at max 1200mm centers.
- Windows and door openings comply with E2 / AS1 (air seals and flashings etc).
Note: Garages are usually built to the standard NZS 4203 where dwellings are built to NZS 3604.