{"id":7605,"date":"2026-08-07T11:33:58","date_gmt":"2026-08-07T03:33:58","guid":{"rendered":"https:\/\/www.lastelegance.com\/au\/?p=7605"},"modified":"2026-09-14T12:49:20","modified_gmt":"2026-09-14T02:49:20","slug":"composite-decking-vs-wood-weight","status":"publish","type":"post","link":"https:\/\/www.lastelegance.com\/au\/composite-decking-vs-wood-weight\/","title":{"rendered":"Composite Decking vs Wood Weight: Real Figures by Board Type"},"content":{"rendered":"\n

A builder specs a subframe for treated pine, then the client switches to composite. The boards show up heavier than planned. Now the joist spacing is wrong, the footings are borderline, and the job stalls before a single board goes down.<\/p>\n\n\n\n

Weight matters more in trade than most guides let on. It sets your subframe spec, your container loading, your freight cost per m\u00b2, and how your crew handles boards on site. A hollow composite board and a solid one can differ by 45%. Freshly treated pine can weigh 50% more than kiln-dried stock. One generic number per material doesn’t cut it.<\/p>\n\n\n\n

This article gives you real kg\/m and kg\/m\u00b2 figures \u2014 composite and Australian timber side by side \u2014 so you can spec, quote, and order with the right numbers.<\/p>\n\n\n\n

How Much Heavier Is Composite Decking Than Wood?<\/h2>\n\n\n\n
\"Equal-length<\/figure>\n\n\n\n

Composite decking ranges from 18 to 30 kg\/m\u00b2, depending on profile. Treated pine sits around 10 kg\/m\u00b2. Australian hardwoods run 16 to 20 kg\/m\u00b2.<\/strong> The real gap depends on four things: board profile (hollow or solid), board dimensions, timber species, and moisture content.<\/p>\n\n\n\n

A hollow composite board at 139\u00d722 mm weighs 2.51 kg per linear metre \u2014 lighter than spotted gum at 140\u00d719 mm (2.53 kg\/m). Switch to a solid composite at 140\u00d723 mm, and the weight jumps to 4.20 kg\/m \u2014 heavier than any common Australian decking timber.<\/p>\n\n\n\n

The point: “composite vs wood” isn’t one comparison. It’s several, and the numbers shift with every variable.<\/p>\n\n\n\n

Why Is Composite Decking Heavier?<\/h2>\n\n\n\n
\"Close-up<\/figure>\n\n\n\n

Composite boards blend wood fibre with HDPE plastic. The mix is heated and pressed, which removes the air pockets found in natural wood. Plastic fills gaps that timber leaves open, so the board ends up denser per metre.<\/p>\n\n\n\n

A typical capped composite uses hardwood fibre combined with HDPE at around 0.95 g\/cm\u00b3 density, with recycled content making up about 60% of the mix. The composite board is simply more packed with material than pine.<\/p>\n\n\n\n

That density is also what makes composite waterproof and termite-proof. More material per metre means no entry points for moisture or insects.<\/p>\n\n\n\n

Real Weights \u2014 Composite vs Timber Per Metre<\/h2>\n\n\n\n

This is where the numbers matter. The table below compares capped composite deck boards against common Australian timber species \u2014 in both kg per linear metre<\/strong> (how you buy it) and kg per square metre<\/strong> (how you spec a subframe and calculate dead load).<\/p>\n\n\n\n

\"Builder<\/figure>\n\n\n\n

The kg\/m\u00b2 column uses nominal board face width with no gap allowance. All timber figures assume kiln-dried stock at 12% moisture content.<\/p>\n\n\n\n

Board type<\/th>Dimensions (mm)<\/th>kg\/m<\/th>kg\/m\u00b2<\/th><\/tr><\/thead>
Capped hollow composite<\/td>139 \u00d7 22<\/td>2.51<\/td>18.1<\/td><\/tr>
Capped hollow composite<\/td>139 \u00d7 23<\/td>2.90<\/td>20.9<\/td><\/tr>
Capped solid composite<\/td>139 \u00d7 24<\/td>3.10<\/td>22.3<\/td><\/tr>
Capped solid composite<\/td>140 \u00d7 20<\/td>3.72<\/td>26.6<\/td><\/tr>
Capped solid composite<\/td>140 \u00d7 23<\/td>4.20<\/td>30.0<\/td><\/tr>
Treated pine (radiata)<\/td>140 \u00d7 19<\/td>~1.45<\/td>~10.4<\/td><\/tr>
Merbau<\/td>140 \u00d7 19<\/td>~2.19<\/td>~15.7<\/td><\/tr>
Spotted gum<\/td>140 \u00d7 19<\/td>~2.53<\/td>~18.1<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Composite weights are from LastElegance product specifications. Other capped composite brands on the Australian market will fall within a similar range for comparable profiles and dimensions. Timber weights are calculated from published air-dry densities: treated pine at 545 kg\/m\u00b3 (Business Queensland), merbau at 825 kg\/m\u00b3 (USDA Wood Handbook), spotted gum at 950 kg\/m\u00b3 (Business Queensland). Actual timber weights vary by grade, cut, and moisture \u2014 always confirm from your supplier’s latest spec sheet.<\/em><\/p>\n\n\n\n

Three things stand out. Treated pine is the lightest option by a wide margin. A hollow composite board weighs about the same as spotted gum per linear metre. And the gap between hollow composite (18 kg\/m\u00b2) and solid composite (30 kg\/m\u00b2) is larger than the gap between treated pine and hardwood.<\/p>\n\n\n\n

Need the total weight for a specific project?<\/strong> Our Decking Calculator<\/a> returns net board weight in kilograms alongside your full material schedule \u2014 boards, joists, clips, and waste allowance.<\/p>\n\n\n\n

How Board Profile Changes the Number<\/h3>\n\n\n\n

Compare two composite boards at roughly the same width: a capped hollow profile at 139 mm weighing 2.90 kg\/m, vs a capped solid profile at 140 mm weighing 4.20 kg\/m. That’s a 45% difference from the profile change alone.<\/p>\n\n\n\n

A hollow composite board can weigh less<\/em> than dense hardwood like spotted gum. A solid composite board will weigh more. Profile matters as much as the material itself when you’re speccing a subframe or costing freight. For a deeper look at the trade-offs \u2014 strength, install, and cost \u2014 see our Hollow vs Solid Composite Decking<\/a> guide.<\/p>\n\n\n\n

Why Timber Weight Varies on Site<\/h3>\n\n\n\n

Timber weight changes with species, moisture content, and grade. The species gap is large: treated pine (radiata) sits around 545 kg\/m\u00b3 kiln-dried, while spotted gum reaches 950 kg\/m\u00b3. That’s nearly double the density for the same volume.<\/p>\n\n\n\n

Moisture is the other variable. Freshly treated pine can hold 50% or more extra water weight compared to kiln-dried stock. Those “light” pine boards off the truck can feel closer to hardwood until they dry out.<\/p>\n\n\n\n

Timber doesn’t have a single weight \u2014 it has a range, and that range is wide. When you’re planning a subframe, costing freight, or comparing quotes, always ask: which species, and how dry?<\/p>\n\n\n\n

How Weight Affects Container Loading and Landed Cost<\/h2>\n\n\n\n

This is where weight stops being a spec-sheet detail and starts setting your cost per m\u00b2.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

A 40′ container carries roughly 22 tonnes of net cargo<\/strong> on Australian roads once you subtract the truck, chassis, and container tare weight. Composite decking \u2014 especially solid profiles \u2014 tends to hit that weight limit well before it fills the container volume. That means tonnage, not unit price, often sets your landed cost per square metre.<\/p>\n\n\n\n

Run the numbers on two common profile types:<\/p>\n\n\n\n