Flood-prone land
Flood mapping sets a flood planning level that drives minimum finished floor heights, stormwater strategy and sometimes evacuation considerations. It usually points to a DA. The design has to lift habitable floors above the flood planning level while keeping the streetscape and access working.
Bushfire-prone land (BAL)
If your block is mapped bushfire-prone, a Bush Fire Attack Level (BAL) assessment determines the construction standard and setbacks to vegetation, per Planning for Bush Fire Protection. Higher BAL ratings add cost and design constraints, and most bushfire situations require a DA rather than CDC.
Heritage items and conservation areas
A heritage listing or a location within a heritage conservation area (HCA) removes CDC eligibility and requires a DA supported by heritage input. The design has to respond to the significance of the item or the character of the area, contemporary duplexes can still succeed with a considered approach.
Frequently asked questions
Not usually, but it changes the pathway (typically DA) and the design. Floor levels, construction standards and setbacks all respond to the overlay. We assess it before design so there are no surprises.
Authoritative sources: NSW Rural Fire Service, Planning for Bush Fire Protection, NSW Planning Portal.