How to Read a Building Contract in NSW

Learn more about our home renovation by Dura Group across Sydney’s south.

A building contract is the most important document in your renovation or building project. Working with a licensed home builder or managing trades separately? Either way, the contract defines everything. It defines what’s being built, how much it costs, when it will be finished, and what happens if something goes wrong.

A NSW building contract defines scope of works, price, payment schedule, timeline, variation process, and warranty terms. Understanding these 7 sections protects your money, your timeline, and your rights.

Types of Building Contracts in NSW

Fixed-Price Contract (Lump Sum)

The builder agrees to complete the defined scope of work for a set price. This is what we use at Dura Group. The price only changes if you request a variation (a change to the agreed scope). This gives you cost certainty from day one.

Cost-Plus Contract

The builder charges you the actual cost of materials, labour, and subcontractors, plus a margin (usually 15 to 25%). You pay for what’s used. This can work for complex projects where the scope is hard to define upfront, but it offers less cost certainty. See our comparison of cost-plus vs fixed-price for more detail.

Key Sections to Understand

Scope of Works and Specifications

This is the most important part of the contract. This section describes in detail:

• Exactly what work is being done
• Materials and products being used (brand, model, colour where applicable)
• What’s included and what’s excluded
• Quality standards and finishes

The more detailed this section, the fewer disputes later. Vague descriptions like “standard kitchen” or “quality tiles” mean nothing. You want specific brands, sizes, and quantities.

Contract Price

The total price is clearly stated, including GST. Check whether the price includes:

• Council approval fees
• Engineering and certification
• Site preparation (demolition, excavation, tree removal)
• Temporary services (fencing, scaffolding, site toilet)
• BASIX certificate requirements

Provisional Sums and Prime Cost Items

Provisional sums are estimates for work where the exact cost isn’t known at contract signing (like excavation on an unknown site). Prime cost (PC) items are allowances for materials you’ll select later (like tiles, tapware, or appliances).

Watch these carefully. If a contract has large provisional sums or low PC allowances, the final cost will likely exceed the contract price. At Dura Group, we minimise provisional sums by doing thorough site assessments upfront and letting you choose materials before signing.

Payment Schedule

The contract specifies a payment schedule tied to completed stages, not calendar dates. A typical schedule:

• Deposit (max 10% in NSW for contracts over $20,000)
• Slab or base stage
• Frame stage
• Lock-up (roof on, windows in, external doors fitted)
• Fixing stage (internal fit-out)
• Completion/final payment

Never pay for work that hasn’t been completed. If a builder asks for payment ahead of completed milestones, that’s a red flag.

Timeline and Completion Date

The contract includes a start date, an estimated completion date, and provisions for delays. Legitimate reasons for delays include weather, council hold-ups, and material supply issues. Check how delays are handled and communicated.

Variations

A variation is any change to the agreed scope of work. The contract requires all variations to be:

• Documented in writing
• Priced before the work is done
• Signed by both parties

Verbal variation agreements are a major source of disputes. If it’s not in writing, it didn’t happen.

Defect Liability Period

After handover, the builder is responsible for fixing any defects that appear. In NSW, the statutory warranty periods are:

• Structural defects: 6 years
• Non-structural defects: 2 years

Your contract may offer additional warranty coverage. Check what the process is for reporting and fixing defects.

Dispute Resolution

The contract outlines a process for resolving disagreements. This typically starts with direct negotiation, then mediation, then (if needed) NSW Fair Trading or the NSW Civil and Administrative Tribunal (NCAT).

Before You Sign

• Read the entire contract, including the fine print and any attached schedules
• Check that the scope matches what you discussed
• Verify the builder’s licence and insurance (see how to choose a builder in Sydney)
• Understand the payment schedule and what triggers each payment
• Ask about anything you don’t understand. Our questions to ask your builder guide covers what to raise
• Consider getting independent legal advice (a building contract review costs $500 to $1,500)

How Dura Group Handles Contracts

Our contracts are detailed, transparent, and designed to protect both parties:

• Fixed-price with minimal provisional sums
• Detailed specifications for every element of the build
• Milestone-based payments tied to completed work
• Written variation process for any changes
• Clear warranty terms exceeding statutory minimums

We want you to feel confident about what you’re signing. Mark walks through every section of the contract with you before you commit.

We work with homeowners in Loftus home builders, Woolooware builders, Kareela builders, and across the Sutherland Shire. Contact Dura Group or call Mark on 0424 665 793.

Frequently Asked Questions

What is the maximum deposit a builder can charge in NSW?

For contracts over $20,000, the maximum deposit is 10% of the contract price. For contracts under $20,000, there is no statutory limit.

What is a provisional sum in a building contract?

A provisional sum is an estimated cost for work that can’t be precisely priced at contract signing. The actual cost may be higher or lower. Watch for large provisional sums as they reduce price certainty.

How long is the warranty on building work in NSW?

In NSW, statutory warranties cover structural defects for 6 years and non-structural defects for 2 years from the date of completion.

Should I get legal advice before signing a building contract?

Yes, especially for contracts over $100,000. A building contract review by a solicitor costs $500 to $1,500 and can save you from costly disputes later. For current construction rates to benchmark your quote against, see our Sydney building costs guide. An initial planning review covers your site conditions, zoning, and the approval pathway that suits your project.