Choosing a timber
Spotted gum and blackbutt are popular local hardwoods with good durability, and some hardwoods are commonly specified on bushfire-prone sites. Merbau is a popular imported option with a rich red-brown colour. Ask your builder about the durability class, grade and supply of the timber they quote.
What goes into a good deck
- ✓Footings and a subframe to AS 1684 or an engineer’s design
- ✓H4-treated posts where timber is in the ground, H3 for bearers and joists
- ✓Galvanised stirrups to keep posts off damp soil
- ✓Stainless or concealed fixings, especially near the coast
- ✓Board gaps to suit the timber and any bushfire requirements
Building on bushfire-prone land
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.
Typical cost
As a guide, low-level Australian hardwood decks (spotted gum or merbau) typically range from $450 to $680 per square metre, while elevated decks needing taller posts, stairs and balustrading, or composite boards, generally range from $650 to $950+ per square metre. Your builder will give you a firm price after measuring up on site.
Approvals, bushfire and structure
Before you build, check whether the deck needs approval, whether your block is bushfire prone, and whether it needs a balustrade. See deck approvals and structural specs for a plain-English summary, then confirm with your certifier or Shoalhaven City Council.
Frequently Asked Questions
How much does a hardwood deck cost per square metre?+
As a guide, low-level Australian hardwood decks (spotted gum or merbau) typically range from $450 to $680 per square metre, while elevated decks needing taller posts, stairs and balustrading, or composite boards, generally range from $650 to $950+ per square metre. Your builder will give you a firm price after measuring up on site.
Will a hardwood deck need oiling?+
Yes, if you want to keep the colour. Untreated hardwood weathers to silver-grey. Most owners oil or coat their deck after it’s built and then maintain it regularly.
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.