Most granny flats in NSW are approved by one of two routes: a complying development certificate (CDC) issued by a certifier, or a development application (DA) lodged with council. Your lot and your design decide which one fits, not personal preference. Our CDC or DA: picking the approval your home project needs covers the general differences. This article applies them to granny flats.
The checklist for a granny flat CDC
A granny flat can be approved as complying development only when every one of these is true:
- The lot is 450 m² or larger, unless the granny flat sits entirely inside the existing house.
- The zone allows secondary dwellings. That means R1 to R5, or another zone your LEP opens up.
- The design meets every Schedule 1 standard in the Housing SEPP, covering lot width, height, setbacks, landscaped area and open space.
- The floor area stays within 60 m² (or a larger figure your LEP allows), and the house and granny flat together stay within the limit for a dwelling house on that lot.
- The land isn't excluded from complying development, for example bush fire land at the two highest ratings, BAL-FZ (flame zone) and BAL-40, high hazard flood areas, or certain heritage land and environmentally sensitive areas.
- A main house already stands on the lot, or is going up alongside the granny flat. The Housing SEPP allows both to be approved together as one complying development.
If all of these line up, a CDC works like a pass or fail test against fixed standards. There is no merit assessment, and "close enough" doesn't pass.
When council is the better or only path
A DA is needed whenever the site or the design falls outside the CDC standards. The usual triggers are:
- a lot smaller than 450 m²
- a design that goes past a height or setback standard, even slightly
- heritage constraints where complying development isn't allowed
- bush fire land at BAL-FZ (flame zone) or BAL-40, or serious flood constraints
- rural zones where the LEP's clause 5.5 sets its own size and separation limits
A DA lets council weigh a variation against its actual impact, so it suits tricky sites and designs. The trade-offs are a merit assessment, notification under council's own policy, and consent conditions you have to satisfy before building. Once consent is granted, a construction certificate is still required before any work starts.
Neighbours are told either way
A CDC is not a quiet approval. In metropolitan Sydney and similar areas, neighbours within a 20 metre radius receive a written letter from the certifier or council, and the CDC can only be approved once 14 days have passed. After the certificate issues, those same neighbours get a second notice before building starts. In metropolitan areas that notice goes out a week or more ahead; in rural and regional areas, and in residential release areas, two days is enough. Neighbours can't lodge a submission at that second stage. Our guide to CDC neighbour notification: who gets told and when goes through the details.
Deciding which way to go
Begin with your planning certificate and a detailed site survey. Then test the design against every CDC standard. If it misses by a small margin, compare two options: redesigning to fit, or taking the original design to council. Small moves, such as shifting a wall, changing the roof pitch or trimming a deck, can sometimes bring a design back inside the code.
The quickest way to know where you stand is a plan assessment before you lodge. We check the drawings against the Housing SEPP standards and the building code, then explain clearly which parts of the design have to move. CertifiBuild can issue the CDC where the design complies, or the construction certificate once council has granted a DA, and can act as principal certifier through to occupation. Visit our granny flats page or request a quote.
Local help across NSW
CertifiBuild certifies Class 1 and Class 10 work in 39 council areas. Local rules on these council pages are a good place to start: City of Newcastle, Wollondilly Shire Council, Hawkesbury City Council, Shellharbour City Council, Cumberland City Council, Wollongong City Council.
Suburb pages with local planning notes: Adamstown, Albion Park, Albion Park Rail, Appin, Auburn, Balgownie, Bardwell Park, Warabrook, Warragamba, Yarramundi. You can also browse every service area.
Sources
- Secondary dwellings guidance, NSW Department of Planning
- State Environmental Planning Policy (Housing) 2021, NSW Legislation
- Telling neighbours about complying development, NSW Planning Portal