Plenty of low, modest decks off the back door go ahead in NSW without approval. The state exempt development rules put firm caps on floor height, deck size and position. Exceed any one and the deck needs a complying development certificate (CDC) or a development application (DA).
What the exempt rules cover
Decks share one set of exempt rules with balconies, verandahs, terraces, patios and pergolas. Those rules are found under Part 2, State Environmental Planning Policy (Exempt and Complying Development Codes) 2008. As with all exempt work, the deck must satisfy every standard. Partial compliance doesn't count.
Exempt development can't be done on a heritage item or draft heritage item, land on the State Heritage Register, critical habitat or wilderness areas. In a heritage conservation area, the deck can't project toward the street past the building line.
The height and size caps
The NSW Planning Portal and the planning department's fact sheet list these caps for an exempt deck:
- Deck floor: 1 m maximum, measured from the natural ground below.
- Highest point: 3 m maximum above natural ground, which mostly matters for a deck with a roof.
- Deck size: 25 m² maximum.
- All such structures combined: where the lot exceeds 300 m², a cap of 15% of the home's ground floor area. Where the lot is 300 m² or smaller, a 25 m² cap.
- Enclosing walls: 1.4 m maximum height.
The combined cap catches people out. An existing patio or verandah counts toward it, so a new deck may push the lot over even when the deck alone is under 25 m².
Location and setbacks
- Kept to the house side of the building line on every road frontage.
- 900 mm or more from each side or rear boundary in residential zones generally. Rural zones and R5 need 5 m.
- Where the deck is roofed and that roof connects to the house, that roof stays below the house's gutters, and any fascia connection follows an engineer's design.
Other conditions apply. Any metal has to be factory pre-coloured with a low reflective finish. Rain from any roof drains to an existing stormwater system without disturbing current drainage. On bush fire prone land, enclosing walls must be non-combustible if the deck is closer than 5 m to the home.
Measuring floor height where the ground slopes
The floor height cap uses existing ground level, which means the ground as it was before any work. On a slope, a deck that is flush with the back door might sit 600 mm up at one end and well over 1 m at the other. Every part of the deck must comply, so take the measurement where the ground under the deck is lowest, not at the house.
Building up the ground with fill doesn't help. The cap relies on the levels that existed before work began.
Exempt decks still need to be built properly
Exempt means no approval, not no rules. The deck must still comply with the building code and be structurally adequate. That covers footing depth, bearer and joist sizes and spans, timber durability and fixings.
Height also links to safety. The building code requires a balustrade wherever a person might drop 1 m or more to the surface below. Because ground often falls away from a house, part of an exempt deck can still need one. See our guide on Deck balustrades: heights, gaps and climbable elements.
If your deck goes over the limits
A higher or larger deck may qualify as complying development through the Housing Code, if both the lot and the deck are eligible. If not, council assesses a development application, and a construction certificate is issued before work starts. For decks with a roof, see our guide on Pergola or roofed patio? How the roof changes the approval.
CertifiBuild certifies decks, pergolas and patios across NSW. If you're unsure whether your design is exempt, a plan assessment can check it against the rules before you build, or you can request a quote for a CDC.
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: Burwood Council, Fairfield City Council, Hornsby Shire Council, North Sydney Council, Waverley Council, City of Sydney.
Suburb pages with local planning notes: Burwood Heights, Canley Heights, Cheltenham, Cremorne, Dover Heights, Forest Lodge, Guildford West, Homebush West, Huntleys Point, Katoomba. You can also browse every service area.
Sources
- Fact sheet on exempt decks, patios, pergolas and verandahs, NSW Department of Planning
- Exempt decks, patios and pergolas, NSW Planning Portal
- Housing Provisions, barriers and handrails (Part 11.3), ABCB