Published 12 November 2026
The choice in one paragraph
Choose hardwood if you want a traditional timber face, you are prepared to oil it (or you are happy for it to weather to silver-grey), and the species is suitable for your site, including any bushfire requirements your certifier sets. Choose composite if you want to skip oiling, you prefer a consistent manufactured board, and the product is rated for your use and, where relevant, your Bushfire Attack Level. The frame underneath — footings, posts, bearers and joists — should still be designed properly either way, to AS 1684 or an engineer’s design.
Hardwood: look, maintenance and species
Hardwood decks in this area are commonly spotted gum or blackbutt, with merbau as a popular imported option, usually in 90 mm or 140 mm boards. The colour is the reason many people choose them, and it will fade in the sun unless you oil and maintain the deck. Untreated, the boards weather to grey. That can look handsome; it is not a defect, but it is a different look from the day the deck was finished.
Hardwood is a natural product, so boards vary, and they will move a little with the seasons. Gaps, fixings and a frame that drains well matter as much as the species. Near the coast, stainless or similarly durable fixings are worth asking about. Some hardwoods are commonly specified as bushfire-resisting at certain BALs under AS 3959, but the rules change with the BAL — confirm the species with your certifier, not from a brochure alone.
Composite: maintenance, heat and the fine print
Composite decking is made from wood fibre or similar materials and plastics. The usual appeal is that it does not need oiling and is less prone to splinters, which suits pool areas and busy family decks. Boards are often fitted with hidden clips. Brands you will hear as examples include Ekodeck, Trex, ModWood and Millboard — examples, not a shortlist you have to choose from, and not a claim that every range suits every site.
Composite usually costs more to install than a simple low-level hardwood deck, and it can get hot in full sun, especially in darker colours. Each brand sets its own joist spacing, ventilation and gap rules, and some products are tested for certain BALs while others are not. Ask which range is being quoted, what the warranty actually covers, and whether it is suitable for your BAL if the land is bushfire prone. Confirm that last point with your certifier.
Coastal blocks and bushfire-prone blocks
At Callala Bay, Culburra and Vincentia, salt air is hard on fixings and stirrups, whatever the board is. Ask about stainless or hot-dip galvanised hardware, and about a frame that is kept off damp soil. Composite’s low maintenance is popular here because oiling a seaside deck is a real chore; hardwood still looks at home if you are willing to maintain it.
Inland and on bushland edges around Cambewarra and Tapitallee, many blocks are mapped as bushfire prone. AS 3959 sets construction requirements for each BAL, which can affect the board, the gaps and the subfloor. Do not assume a favourite composite, or a favourite hardwood, is automatically acceptable. Get the BAL assessed and check the product and the species before you order a stack of boards. Our approvals and structural specs page summarises that, and a certifier should confirm it.
The frame is not optional
A beautiful surface on a tired or undersized frame is a short-lived win. Decks should be framed to AS 1684 (Residential timber-framed construction) or an engineer’s design, typically with galvanised stirrups, H3- or H4-treated timber in the right places, and posts kept out of damp soil. If you are replacing only the boards on an old deck, have the joists and posts inspected first. Our guide to signs your deck needs a rebuild covers that inspection.
Covered decks and the surface choice
If you are also building a roof or a pergola over the deck, that can change how the surface weathers — hardwood under a roof needs less frequent oiling — and it can change the approval path, because roofed structures have extra exempt-development conditions. The board choice and the roof should be designed together, including falls, drainage and any ceiling fans, which have to be wired by an electrician who is authorised to do that work. Our covered pergolas page is the place for the roof itself; just do not pick a board in isolation from the roof plan.
Price, without a number that pretends to be a quote
We have not repeated a square-metre rate in this article. Installed prices vary with height, stairs, balustrades, access, the species or the composite range, and the site. Elevated decks and more complex shapes sit in a different bracket from a low, simple rectangle. The builder you are matched with should measure up and give you an itemised price. Compare the same scope: frame, boards, fixings, stairs and any roof or screening.
Nowra Deck Co is a lead-matching service connecting property owners with independent deck builders. We do not build the deck ourselves. Call 0415 770 509 with your suburb, a rough size and height, and whether you are leaning towards timber or composite.
For a quote on a hardwood or composite deck in Nowra or the Shoalhaven, call 0415 770 509 and we will match you with an independent local deck builder. Mention whether your block is bushfire prone, and any brand you already prefer.