Choosing between timber and composite decking is one of the first decisions you will make when planning a new deck. Both options have vocal supporters online, and both have real strengths. But most of the comparisons you will find leave out the numbers that actually matter: the total cost of owning that deck over 10 and 20 years, not just what it costs to install.
This guide compares timber and composite decking on upfront cost, ongoing maintenance cost, lifespan, appearance, and performance in Western Sydney’s climate. The goal is to give you the information you need to make the right call for your block, your budget, and how much time you want to spend maintaining your deck.
Upfront Cost Comparison
Timber decking is cheaper to install. Composite decking costs more upfront. That part is straightforward.
Here are the typical supply and installation costs per square metre in the Macarthur and South West Sydney region for 2026.
Hardwood timber decking (Spotted Gum, Blackbutt, or Merbau): $320 to $550 per square metre installed. The range depends on the species, the grade, and the complexity of the deck frame. Spotted Gum and Blackbutt sit at the higher end. Merbau is generally mid-range but prices fluctuate with import supply.
Treated pine decking: $180 to $280 per square metre installed. This is the budget timber option. It is structurally sound but softer, more prone to splintering, and requires more frequent maintenance than hardwood.
Composite decking (capped polymer or wood-plastic composite): $450 to $750 per square metre installed. Premium brands with solid core profiles and long warranties sit at the top of this range. Budget composite products with hollow cores sit at the lower end.
For a typical 25 square metre deck, the installed cost breaks down roughly like this:
- Treated pine: $4,500 to $7,000
- Hardwood timber: $8,000 to $13,750
- Composite: $11,250 to $18,750
On day one, timber wins on price. But day one is not where the real comparison happens.
The Maintenance Cost Nobody Mentions
Timber decking needs regular maintenance to stay looking good and to last. Composite decking needs almost none. Over 10 and 20 years, this gap adds up to thousands of dollars and dozens of hours.
Hardwood timber maintenance schedule:
- Oiling or staining every 12 to 18 months to maintain colour and protect against UV damage and moisture. A quality decking oil costs $60 to $100 per tin, and a 25 square metre deck needs two to three coats per application. If you do it yourself, budget $150 to $250 per year in materials. If you hire someone, it costs $400 to $800 per application.
- Light sanding every two to three years to remove grey weathering, raised grain, and minor surface damage before re-oiling.
- Board replacement as needed. Even the best hardwood decks will have the occasional board that splits, cups, or warps over time. Individual board replacement costs $50 to $150 per board depending on the species and access.
Over 10 years of DIY maintenance, a hardwood deck costs roughly $1,500 to $2,500 in materials alone. If you pay a professional to oil and sand it, that number climbs to $4,000 to $8,000.
Over 20 years, you are looking at $3,000 to $5,000 in DIY maintenance costs or $8,000 to $16,000 in professional maintenance costs. Plus the time. Oiling a 25 square metre deck takes a full weekend including prep, wash, dry, and two coats.
Composite maintenance schedule:
- Wash with soapy water and a soft broom once or twice a year.
- No oiling. No staining. No sanding. No sealing.
Over 10 years, composite maintenance costs are effectively zero beyond the soap and water. Over 20 years, the same.
Total Cost of Ownership: The Real Comparison
When you add the upfront cost and the maintenance cost together, the gap between timber and composite narrows significantly over time. For some homeowners, it disappears entirely.
25 square metre hardwood deck, total cost over 20 years:
- Installed: $8,000 to $13,750
- Maintenance (DIY): $3,000 to $5,000
- Total: $11,000 to $18,750
25 square metre composite deck, total cost over 20 years:
- Installed: $11,250 to $18,750
- Maintenance: negligible
- Total: $11,250 to $18,750
The 20-year total cost is nearly identical for mid-range hardwood and mid-range composite. The difference is that with composite, you pay more upfront and then nothing afterward. With timber, you pay less upfront and then keep paying every year in time, materials, or professional maintenance.
If you pay a professional to maintain the timber deck, composite comes out cheaper over 20 years.
Lifespan: How Long Each Option Actually Lasts
Lifespan claims are where the marketing gets slippery. Both timber and composite manufacturers make big promises. Here is what you can realistically expect in Western Sydney’s climate.
Hardwood timber (Spotted Gum, Blackbutt, Ironbark): 25 to 40 years with proper maintenance. The subframe (bearers and joists) may last longer than the deck boards themselves if it is well-ventilated and kept off the ground. Without maintenance, hardwood can deteriorate within 8 to 12 years due to UV damage, moisture cycling, and insect activity.
Treated pine: 10 to 15 years with maintenance. Treated pine is softer and more vulnerable to wear, splitting, and rot than hardwood. It is a budget option that does not last as long.
Composite decking: 25 to 30 years based on manufacturer warranties for premium capped products. The actual lifespan may be longer, but composite decking has only been widely used in Australia for about 15 years, so we do not yet have real-world data beyond that point. Budget composite products with uncapped or hollow-core profiles have shorter lifespans, typically 10 to 15 years.
The critical variable for timber lifespan is maintenance. An oiled, well-maintained hardwood deck will outlast an identical deck that gets ignored. For composite, the lifespan is more predictable because it does not depend on the owner doing anything.
Performance in Western Sydney’s Climate
Western Sydney is tough on outdoor materials. Summer temperatures regularly exceed 40 degrees. UV exposure is intense. Afternoon storms can drench a deck and then the next day bakes it dry. This heat and moisture cycling is the primary enemy of both timber and composite decking, but they respond to it differently.
Timber in heat: Hardwood handles temperature well. It does not get as hot underfoot as composite in direct sun, which matters if you have kids or pets who use the deck barefoot. The boards expand and contract with moisture changes, but a properly spaced hardwood deck accommodates this movement naturally.
Composite in heat: Darker composite colours absorb more heat and can become uncomfortably hot underfoot in full sun. Some premium composite brands now offer “cool touch” or lighter colour options designed to reflect more heat. If your deck will be in full sun with no shade from a pergola or roof, surface temperature is a genuine consideration.
Timber in rain: Timber absorbs moisture, which is why it needs oiling. Unsealed timber will grey, crack, and eventually rot if left exposed. Proper drainage, ventilation underneath the deck, and regular oiling mitigate this.
Composite in rain: Composite does not absorb moisture. Capped composite boards have a polymer shell that repels water. This means no swelling, no warping, and no rot. It also means composite decks dry faster after rain and do not develop the mould problems that neglected timber decks can.
UV exposure: Both materials are affected by UV. Timber greys and loses colour without regular oiling. Composite can fade slightly over the first one to two years and then stabilises. Premium capped composite products fade less than uncapped ones.
Appearance and Feel
This is subjective, but it matters.
Timber has a natural warmth and grain pattern that composite replicates but does not quite match. If you value the look and feel of real wood, timber delivers something composite cannot fully replicate. Each board is unique. The grain varies. It feels like a natural material because it is one.
Composite has improved dramatically in appearance over the past decade. The best products now feature multi-tonal colour streaking and realistic wood grain textures. From a distance, modern composite is hard to distinguish from timber. Up close, it still feels like a manufactured product.
The aesthetic gap has narrowed, but it has not closed completely. If you care about the tactile feel and visual warmth of natural timber, that is a legitimate reason to choose it.
Which One Should You Choose
Choose timber if you enjoy maintaining your outdoor spaces (or do not mind paying someone to), you value the natural look and feel of real wood, you want a lower upfront cost, and your deck will be in full sun where composite heat is a concern.
Choose composite if you want minimal ongoing maintenance, you prefer a predictable total cost with nothing to pay after installation, you want consistent colour and appearance without annual oiling, and you are building in a location where moisture exposure is high (near a pool, under trees, or in a shaded area prone to mould).
Consider combining both. Some homeowners use a hardwood timber subframe (which is structurally superior and hidden from view) with composite deck boards on top. This gives you the structural performance of timber where it matters and the low-maintenance surface of composite where you walk on it.
Your deck builder can walk you through the material options and recommend the best fit for your block, your budget, and how you plan to use the space. Token Building installs both timber and composite decks across the Macarthur and South West Sydney region.
Get in touch for a free consultation and we will help you choose the right material for your project.