Accurate site details are essential for calculating the water, thermal, and energy performance of the development. It is important that these details are entered accurately, as they will impact your assessment pathway and performance criteria.
Project details
- Site area: the total area of land on which the proposed development is to be carried out
- Roof area: the total area of all roof surfaces, measured to the outside of the gutters and in the horizontal plane. Excludes parapets and trafficable roof terraces
- Number of storeys: the number of enclosed levels in a building, where a storey is the space between one floor level and the level above. This does not include:
- spaces containing only a lift shaft, stairway or meter room
- mezzanines
- non-habitable attic storage spaces
- lower-level garages, workshops, or storerooms
- Conditioned floor area: the total fully enclosed floor area of the dwelling, excluding:
- areas that are not fully enclosed
- bathrooms (excluding ensuites) and laundries with a ventilation opening
- voids, storerooms, garages and carparks
- Unconditioned floor area: the total floor area of all bathrooms and laundries with a ventilation opening (excluding ensuites)
- Garage area: the area of an enclosed garage area. Excluding carports
- Mezzanine area: habitable areas open to and above a habitable floor. Excludes stairs, stair landings, open passageways, gantries and corridors 1.1m wide or less
NOTE: If you are using the simulation pathway for thermal comfort, floor areas may be taken directly from the thermal model.
Pools and spas
If your development includes a pool (indoor or outdoor) and/or outdoor spa, you must select these on the Building details page to appear in the water and energy sections of the BASIX tool. This selection can be updated later if a pool or spa is added.
- Swimming pool: Select ‘Yes’ to include an indoor or outdoor pool
- Outdoor spa: Select ‘Yes’ to include an outdoor spa. Note that indoor spas located in bathrooms are not included in BASIX.
Last updated: 29/04/2026