Contract Works and Public Liability Insurance for Builders: What’s Covered and What’s Not

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If you hold a building contract, you almost certainly have an obligation to insure the works — and to carry public liability. Contract works and public liability insurance are the two covers nearly every residential and commercial builder in Australia buys, usually packaged together. They’re also the covers where builders most often discover a gap at exactly the wrong moment: after the loss. Here’s how the two sections work, how annual and single-project policies differ, and where the common gaps sit.

Two Covers, One Policy

Most builders’ policies are written in two sections:

  • Section 1 — Contract works (material damage): covers physical loss or damage to the building works themselves while they’re under construction — fire, storm, water damage, vandalism, theft of incorporated materials, and accidental damage. Cover typically runs from site commencement until practical completion or handover, with a limited extension into the defects liability period.
  • Section 2 — Public liability: covers your legal liability for personal injury or third-party property damage arising from your business activities — a member of the public injured near the site, damage to a neighbour’s property, a subcontractor’s grinder starting a fire that spreads.

The two sections answer different questions. Contract works asks: what if the project itself is damaged? Public liability asks: what if the project damages someone else? Builders need both — and neither covers defective workmanship itself, professional design errors, or injuries to your own workers (that’s workers compensation).

Annual Policy or Single Project?

  • Annual (turnover-based) policies cover all projects a builder starts during the policy period, declared against estimated annual turnover, with a maximum sum insured per project. For builders running multiple jobs, this is usually more economical and removes the risk of forgetting to insure a job.
  • Single project policies cover one nominated contract from commencement to completion, often used for projects that exceed the annual policy’s per-project cap, for joint ventures, or where the principal requires a project-specific policy.

Two details deserve attention on annual policies: the per-project maximum (a job that grows past the cap mid-build can be underinsured) and the maximum project period (long-running projects can outrun the policy’s standard project duration and need extension).

What the Head Contract Requires

Insurance clauses in building contracts are not standard. Common head contract requirements include:

  • Minimum public liability limits (commonly $10 million or $20 million)
  • The principal and financiers named as interested parties
  • Cover to be maintained through the defects liability period
  • Evidence of currency before site access

On larger commercial projects the principal sometimes arranges the contract works insurance instead (principal-arranged or project-specific insurance). Where that happens, builders should confirm exactly what the principal’s policy covers and what deductibles apply — principal-arranged policies frequently carry large excesses that the contract passes down to the builder, and they rarely cover the builder’s own tools, plant or hired-in equipment.

The Common Gaps

Most contract works claims disputes trace back to a handful of recurring gaps:

  • Defective design and workmanship exclusions. Policies exclude the cost of rectifying defective work itself; where they differ is how much of the resulting damage they cover. The policy wording matters more than the premium here.
  • Existing structures. A renovation or extension policy that covers the new works but not the existing house it’s attached to — a critical gap in residential alteration work.
  • Cover after practical completion. Damage during the defects liability period, or to unsold display homes, needs specific extensions.
  • Tools, plant and equipment. Usually a separate optional section, not automatic.
  • Materials in transit or storage. Off-site materials may need to be specifically covered.
  • Escalation and removal costs. The sum insured should reflect the full rebuild exposure: contract value plus cost escalation, demolition and debris removal, and consultants’ fees — not just the contract price.

Collecting Subcontractor Insurances: The Procedure Most Builders Skip

Your own contract works and public liability policies protect your projects and your liability — they are not a substitute for the insurances of the businesses working under you. When an uninsured or underinsured subcontractor causes a loss, the claim doesn’t politely wait for their insurer: it typically lands on the builder — on your policy (with your excess and your claims history absorbing it) or, where cover doesn’t respond, on your balance sheet. As the head contractor you also carry site-wide duties that make you the natural first target when something goes wrong. An effective procedure for collecting and checking subcontractor insurances is one of the cheapest risk controls a building business can run.

The procedure needs to cover everyone who contributes to the works, not just the trades:

  • Trade subcontractors — public liability as a minimum, plus workers compensation for their own people; check the liability limit meets your head contract requirement, not just theirs.
  • Design consultants — architects, engineers and drafters need current professional indemnity; because PI is claims-made, cover has to be in force when a claim is made, potentially years after the design work.
  • Supply-and-install contractors and material manufacturers — fabricators, facade and roofing system installers, and manufacturers who design or certify what they supply may need public and products liability and PI where design input is part of the package.

What an effective procedure looks like in practice:

  • Certificates of currency before site access — no certificate, no start; collected every engagement, not once per relationship.
  • Check the detail, not just the existence — limits against contract requirements, the business name matching the entity you engaged, and whether the policy actually covers the activity (height, depth, hot work and demolition restrictions are common).
  • Track expiry dates — policies renew annually; a certificate collected in March says nothing about October. Diarise and re-collect.
  • Flow-down insurance clauses in your subcontracts, mirroring what the head contract demands of you.
  • Keep the records for years — defect and injury claims commonly arrive long after completion, and the certificate you collected is your evidence of a responsible engagement process.

Done well, this discipline reduces the chance of your own policies wearing losses that belong to someone else’s insurer, supports your position in disputes, and is increasingly expected by principals and their financiers. Silverback Insurance assists builders in understanding subcontractor insurance requirements and setting up collection procedures that fit how their projects actually run — it’s part of how we look at a building business’s risk as a whole rather than policy by policy.

Residential vs Commercial

The structure of cover is similar, but the exposures differ. Residential builders in NSW also carry separate obligations under the Home Building Compensation scheme for applicable residential work — HBCF cover is distinct from contract works and public liability and doesn’t replace either. Commercial builders more often meet principal-arranged insurance, higher liability limits, and contractual interest clauses. In both cases the discipline is the same: read the insurance clause of the contract before pricing the job, and match the policy to it.

Frequently Asked Questions

Does public liability cover defective work?

No. Public liability responds to personal injury or third-party property damage caused by your business activities. The cost of fixing defective work itself is excluded, and design errors are a professional indemnity matter.

What is the difference between contract works and public liability?

Contract works covers damage to the building works under construction. Public liability covers your legal liability for injury or damage to third parties. They are usually packaged as two sections of one builders policy.

Should I buy an annual policy or insure each project?

Builders running multiple projects generally use annual turnover-based policies with a per-project cap; single project policies suit jobs above that cap or where the contract demands a project-specific policy. The right structure depends on your pipeline — consider both against your actual contracts.

Does contract works insurance cover my tools and equipment?

Not automatically. Tools, plant and hired-in equipment are typically optional sections that must be added.

My contract says the principal arranges the insurance — am I covered?

Possibly for the works, but principal-arranged policies often carry high excesses passed down to contractors and do not cover your tools, plant or liability. Review what the principal’s policy actually includes before relying on it.

If you’d like advice on how these covers apply to your contracts, or a review of your current policy against your head contract requirements, contact us or call Petara on 0410 152 835. Related guides: professional indemnity for NSW builders under the DBP Act and surety bonds vs bank guarantees.

This article is current as at July 2026. The information provided is general advice only and has been prepared without taking into account your particular objectives, financial situation or needs. Silverback Insurance Pty Ltd (CAR 1283436 | ABN 74 643 561 746) is a Corporate Authorised Representative of Australian Broker Network Pty Ltd (AFSL 304 139).