Composite vs Timber Decking Sydney: Cost, Care & Lifespan

Composite vs Timber Decking: Which Suits Your Sydney Home?

There's no single right answer when choosing between composite and timber decking. Hardwood gives you the warmth and grain of real timber; composite trades some of that for far less upkeep. The best choice depends on how you'll use the deck, how much maintenance you'll accept, and what your site throws at it: full sun, a pool, salt air or bushfire risk.

We build both across the Lower North Shore, Northern Beaches and Eastern Suburbs; here are the honest trade-offs. For how we build decks, see our timber and composite decking service.

Hardwood Decking: The Sydney Favourites

Hardwood decking in Sydney usually means one of three species:

• Spotted gum: dense and hard-wearing, with natural colour variation from pale grey-brown to deep chocolate. It's often specified on bushfire-prone blocks, subject to the site's BAL rating.
• Blackbutt: paler and more even, in golden to straw tones that suit coastal and contemporary homes. Light boards stay cooler underfoot, but show dirt and marks more readily.
• Merbau: a rich red-brown imported hardwood that's stable and widely available. It bleeds tannin when new, which can stain nearby paving and pool coping, so plan for run-off and ask for certified, responsibly sourced supply.

Real timber's big advantage is that it can be renewed: a tired hardwood deck can be sanded back and re-oiled to look close to new.

Composite and Capped Composite Decking

Traditional composite boards blend wood fibre with plastic, often with recycled content. Capped composite adds a tougher polymer shell over the core that resists staining, fading and moisture better. Composite won't splinter, doesn't need oiling and resists rot, which is why it's popular around pools and with busy households.

ModWood is an Australian-made wood-plastic composite. Millboard uses a resin-and-mineral board moulded to replicate timber texture rather than a wood-plastic mix. Ekodeck, Ozdeck and Trex are other ranges you'll see in Sydney. Each brand sets its own rules for joist spacing, board gaps and fixings, and following them is usually a condition of the warranty, so ask any composite decking installer how they'll meet them.

For eco-friendly or sustainable decking, both sides have a case: many composites use recycled plastic and timber waste, while hardwood is renewable when it comes from a certified source such as FSC or Responsible Wood.

How They Compare

Cost

Both materials sit within our published range of $350–$650 per square metre installed. Where your deck lands depends less on "timber or composite" and more on the specific board, the frame, deck height, stairs, balustrades, access and any demolition. Our pricing page lists our other published rates.

Maintenance: Oiling vs Washing

Hardwood needs cleaning and re-coating to hold its colour, more often in full sun; re-coat when water stops beading on the surface. If you're happy for timber to weather to silver-grey you can skip oiling, although boards may develop fine surface checks. Composite generally just needs a wash with soapy water and a soft brush a few times a year, but deep scratches can't be sanded out.

Heat Underfoot

Composite, particularly in darker colours, can get noticeably hotter than timber in full summer sun. On north- or west-facing decks, choose a lighter colour whichever material you pick, or plan for shade.

Slip Resistance Around Pools

For pool decking, ask for the product's slip-resistance results in wet, barefoot conditions, and favour textured or grooved boards. Timber in shady, damp spots can grow algae and become slick if it isn't cleaned. Slip-resistant decking isn't always the whole answer: on our Northbridge Retreat project, the pool surround used slip-resistant porcelain tiles with frameless glass fencing. Whatever you build, keep steps, benches and planters clear of the pool fence's non-climbable zone.

Coastal and Salt Exposure

Salt air is hard on fixings, so close to the water use marine-grade stainless steel screws and galvanised hardware. Timber weathers faster in salt and sun and needs more frequent coating. Composite copes well, but a regular rinse stops salt residue building up. Our Seaforth Crescent garden pairs extensive timber decking with a native palette that thrives in coastal salt air.

Lifespan

Built and maintained well, either material should serve you for many years, and in practice the frame usually decides how long a deck lasts.

Look and Feel

Hardwood has genuine grain and colour variation, and it ages with the house. Composite is more uniform; better boards mimic grain convincingly, but up close the difference is usually noticeable.

Bushfire (BAL) Considerations

If your block is mapped as bushfire-prone land, common on bushland edges across the North Shore and Northern Beaches, its Bushfire Attack Level (BAL) under AS 3959 limits which materials and details you can use. Spotted gum and blackbutt are often specified, and some composite and steel-framed systems are tested to particular BAL ratings. Check your BAL assessment before choosing boards.

The Part You Don't See: Substructure and Ventilation

Posts should sit on concrete footings taken down to firm ground, which matters on the reactive clay soils found across parts of the North Shore. Framing should be rated for outdoor use, such as H3 treated pine, hardwood or galvanised steel, with timber posts kept off the ground on galvanised stirrups.

Low decks need airflow and ground that sheds water, or boards cup and frames rot. Composite boards expand and contract with temperature, so gaps and joist spacing must follow the manufacturer's specification. Where the drop from the deck is 1 metre or more, the National Construction Code requires a compliant balustrade.

Restoring vs Replacing an Old Deck

Timber deck restoration, meaning new boards where needed, refixing, sanding and re-oiling, is good value when the frame is sound. Push a screwdriver into the joists, bearers and tops of posts: soft timber, a bouncy feel or badly rusted fixings point to replacement instead.

If you're replacing, don't assume an old timber frame can take new composite boards; it may not meet the brand's spacing and ventilation requirements, and we'll tell you honestly if it doesn't.

Council Approval Basics

Many low, modest decks can be built as exempt development, but NSW rules set limits on size, height above ground and distance from boundaries. Higher or roofed decks, and anything outside those limits, generally need a complying development certificate or a development application, with extra conditions for heritage and bushfire-prone properties. Check with your council or a certifier before you build.

How to Choose

• Choose hardwood if you want real timber, don't mind re-coating, and like being able to sand and refresh the surface.
• Choose composite for low maintenance, pool surrounds, rentals or busy family decks, in a lighter colour for sunny spots.
• On coastal or bushfire-prone sites, let exposure and your BAL rating narrow the options first.
• Compare quotes on the frame, not just the boards: footing depth, framing material, joist spacing and fixings.

As deck builders working across the North Shore and beyond, we're happy to bring samples of both to your site. Our in-house teams are licensed and qualified, we carry $20M public liability insurance, and we have more than 10 years' experience. Quotes are free and on-site: call 0481 057 426.

Frequently Asked Questions

Is composite decking cheaper than timber in Sydney?

Not necessarily. Both fall within our installed range of $350–$650 per square metre, and the board, frame, height and access usually matter more than the material itself. Composite can cost less to look after over time because it never needs oiling.

Which decking is best around a pool?

Composite is often the practical choice because it won't splinter, needs no oiling and resists moisture. Look for textured boards with tested wet slip resistance, in a lighter colour to keep heat down. Hardwood works too, but needs regular cleaning in shady, damp areas.

Can you restore my old timber deck instead of replacing it?

Often, yes. If the footings and frame are sound, new boards where needed plus sanding and re-oiling can bring a hardwood deck back. Rotting joists or bearers make replacement the safer option.

Do you install composite decking in Mosman and North Sydney?

Yes. We install composite and hardwood decks across the Lower North Shore, including Mosman and North Sydney. We'll recommend the boards that suit your site rather than pushing a single brand.