Decking Cost Calculator – How Much Does Decking Cost in Australia?

Thinking of transforming your outdoor area with a beautiful new deck? Whether you’re building a small entertaining space or a large wraparound deck, planning your decking budget is the first step. The total cost of a deck can vary widely depending on materials, size, height, and the complexity of the design.

To help you plan, we’ve created an easy-to-use Decking Cost Calculator. Simply enter your deck size and choose your preferred materials to get a quick estimate of what your project might cost*.

*Please note: The calculator provides an indicative cost for materials and basic installation only. It does not include demolition, permits, stairs, balustrades, or custom work.

How to Calculate the Cost of a Deck

Decking isn’t just about nailing timber planks together. It involves careful planning, structural supports, and the right materials for your space and lifestyle.

To calculate the estimated cost of your decking project:

1. Measure the size of your deck in square metres

2. Select your desired decking material (e.g. treated pine, composite, hardwood)

3. Multiply the size by the material’s average cost per m²

4. Factor in labour, footings, stairs, and any extra features

Or better yet — use the calculator above to get an instant estimate.

Step 1: What Affects the Cost of Building a Deck?

A number of key factors influence decking costs in Australia. Understanding them helps you make informed decisions and stick to your budget.

1. Deck Size

Decks are quoted based on total square metres. The larger the area, the more materials and labour are required. But keep in mind that smaller decks can still be expensive if the design is complex.

2. Type of Decking Material

Your choice of material has a major impact on cost, appearance, and durability.

• Treated pine: Most budget-friendly

• Composite decking: Low-maintenance, mid-to-high cost

• Hardwood (e.g. Merbau, Blackbutt): Premium look, higher price

• PVC or capped composite: Top-tier durability, more expensive

3. Height & Substructure

The higher off the ground your deck is, the more structural support it requires — including posts, joists, and bracing. Elevated decks cost significantly more than low-set ones.

4. Site Conditions

Is your backyard flat and clear, or sloped with restricted access? Challenging terrain may require excavation, levelling, or custom footings, increasing costs.

5. Stairs, Railings & Balustrades

Adding stairs, handrails, or balustrades will increase your project cost — especially if you’re building a raised or multi-level deck.

6. Council Approvals or Permits

Depending on your state and the deck’s size and height, you may need planning approval or a building permit. Always check local council regulations before starting.

Step 2: Measure Your Deck Area

Measuring your deck is easy if you’re working with a basic shape like a square or rectangle:

Deck Area = Length × Width

For example, a deck that is 6m long and 4m wide:
6 × 4 = 24 m²

If your design includes multiple shapes or cut-outs (like around trees or pools), break it into smaller sections and calculate each one separately, then add them together.

Step 3: Average Decking Costs per m² (Australia)

Here’s a general guide to decking costs based on material and complexity:

Prices include subframe, fixings, and basic installation. Complex builds or multi-level decks will cost more.

Example Estimate

For a 20 m² Merbau deck at $350 per m²:
20 × $350 = $7,000

Step 4: Include Additional Costs

In addition to materials and installation, your total cost may include:

Labour

Most deck builders charge a fixed per m² rate, but hourly rates (e.g. $60–$100/hour) may apply for tricky sites or custom work.

Subframe & Footings

Low decks may only need simple bearers and joists. Elevated decks require more structural framing, increasing costs significantly.

Site Preparation

If your site needs clearing, grading, or excavation, this could add $500–$2,000+ depending on difficulty.

Stairs and Railings

Adding stairs costs anywhere from $500 to $3,000+ depending on height and materials. Balustrades or glass handrails can add $200–$600 per linear metre.

Finishing & Sealing

Timber decks often need to be sealed or stained, which adds labour and materials. Some homeowners also choose to add lighting, built-in seating, or planter boxes.

Disposal of Old Decking

Replacing an existing deck? Demolishing and removing old timber or concrete footings can cost $500–$1,500+ depending on size and material.

Step 5: Get Quotes from Licensed Deck Builders

Once you’ve estimated your budget, it’s time to speak with professionals. A good quote should include:

• Material details (species, brand, warranty)

• Inclusions (footings, fasteners, prep work)

• Estimated build time

• Site conditions and access assumptions

• Any council compliance or permit work

Be sure to get at least 3 quotes and compare not just price, but experience, portfolio, and customer reviews.

Decking Repairs vs Replacement

If you already have a deck, consider whether repair or replacement is more cost-effective.

Repair May Be Enough If:

• Only a few boards are warped or cracked

• The frame is still solid and level

• Damage is isolated (not widespread rot or termites)

Full Replacement Is Recommended If:

• The structure is sagging or unstable

• There’s visible rot, corrosion, or termite damage

• Boards or posts are no longer safe

• You want to upgrade materials or expand size

FAQs About Decking Costs

How much does decking cost per m² in Australia?

Depending on the material and complexity, decking costs between $200 and $600 per square metre, including installation.

What is the cheapest decking material?

Treated pine is the most affordable option and widely available. It’s suitable for flat, low-level decks but may require more frequent maintenance.

How long does a deck last?

• Treated pine: 10–15 years (with proper care)

• Hardwood (like Merbau): 20–40 years

• Composite: 25–50 years

• PVC: 40+ years

Can I build a deck myself?

DIY is possible for low, small decks if you have carpentry experience. For larger or elevated decks, it’s safer and more cost-effective to hire a professional.

Do I need council approval to build a deck?

Yes, in most cases — especially if the deck is more than 1 metre off the ground, is over a certain size (e.g. 25 m²), or is attached to your home. Check with your local council before starting.

Ready to Estimate Your Decking Project?

Use our free Decking Cost Calculator to get a quick estimate for your upcoming outdoor project. Choose your material, enter your deck size, and plan your budget in minutes.

When you’re ready, get quotes from licensed, experienced deck builders to bring your outdoor space to life.