Structure: AS 1684 and treated subframes
Decks should be framed to AS 1684 (Residential timber-framed construction) or an engineer’s design. That covers footing sizes, post, bearer and joist spans and the connections that hold it all together. High or complex decks usually need engineering, and decks that need approval are inspected by the certifier.
- ✓Concrete footings with galvanised post stirrups
- ✓H4-treated timber where it’s in the ground
- ✓H3-treated bearers and joists
- ✓Timber kept off damp soil
- ✓Stainless or hot-dip galvanised fixings near the coast
Bushfire-prone land (BAL)
Much of the Shoalhaven is mapped as bushfire-prone land. If your block is, the deck has to meet the AS 3959 construction requirements for its Bushfire Attack Level (BAL), which can affect the timber species, board gaps, subfloor enclosure and fixings. Hardwoods such as spotted gum and blackbutt are commonly specified as bushfire-resisting timbers at some BALs, but the rules change with the BAL. Get the BAL assessed and confirm the specification with your certifier before ordering materials.
Do you need approval?
Some decks can be built in NSW as exempt development, with no Council approval, but only if they meet every condition in the State’s exempt development code. In summary, the deck must be behind the building line, at least 900 mm from each boundary (5 m in some rural and large-lot residential zones), no more than 25 m² in area, with a floor no more than 1 m above existing ground, and the total of all decks, patios and pergolas on the lot must stay within set limits. Roofed decks have extra conditions, such as not sitting above the house’s gutter line. On bushfire-prone land, a deck within 5 m of the house generally has to be non-combustible to be exempt, so most timber decks attached to a house there need a complying development certificate (CDC) or a development application. Heritage items and some other land are excluded. Check the full conditions on the NSW Planning Portal, or with Shoalhaven City Council or a certifier, before you build.
Balustrades (NCC)
Under the National Construction Code (NCC), a deck needs a balustrade or other barrier where its floor is more than 1 m above the surface below. The height, gaps and wire tension are all specified, so ask your builder how the balustrade is designed to meet the NCC.
Licensed builders
In NSW, a contractor licence is needed for residential building work, including decks and pergolas, valued at more than $5,000 in labour and materials. Check the builder’s licence on the NSW Government licence check before you sign, and for work over $20,000 ask for the Home Building Compensation certificate before work starts.
Please note
This page is a general summary as at November 2026, not legal or certification advice. Rules change and every block is different, so confirm with your certifier, Shoalhaven City Council or the NSW Planning Portal.
Frequently Asked Questions
Do I need Council approval for a deck?+
It depends on the size, height, setbacks, whether it’s roofed and whether the land is bushfire prone. Some small, low decks are exempt; many need a CDC or DA. See our approvals summary and check with a certifier or Shoalhaven City Council.
Does my deck builder need a licence?+
In NSW, a contractor licence is needed for residential building work, including decks and pergolas, valued at more than $5,000 in labour and materials. Check the builder’s licence on the NSW Government licence check before you sign, and for work over $20,000 ask for the Home Building Compensation certificate before work starts.
Does my deck need a balustrade?+
Under the National Construction Code (NCC), a deck needs a balustrade or other barrier where its floor is more than 1 m above the surface below. The height, gaps and wire tension are all specified, so ask your builder how the balustrade is designed to meet the NCC.
How Nowra Deck Co works
Nowra Deck Co is a local lead-matching service connecting Nowra and Shoalhaven property owners with independent, licensed carpenters and deck builders. We don’t do the work ourselves. The builder you’re matched with quotes, builds and is responsible for the job. In NSW, a contractor licence is needed for residential building work, including decks and pergolas, valued at more than $5,000 in labour and materials. Check the builder’s licence on the NSW Government licence check before you sign, and for work over $20,000 ask for the Home Building Compensation certificate before work starts.