Certification for builders

Licences and supervision

A contractor licence is required to carry out, advertise or contract for home building work over $5,000 (labour plus materials, GST included). Subcontract work forming part of a bigger job above that value is covered too. Companies and partnerships hold their own licence. Whoever supervises the work needs an endorsed contractor licence or a qualified supervisor certificate.

Licences are issued for 1, 3 or 5 years, so check renewal dates fall after the job ends. Specialist work outside your licence categories must go to a subcontractor licensed for it and be supervised by someone qualified in it. Unlicensed work can be fined up to $22,000 for a person and $110,000 for a company.

What must the site sign show?

Jobs under a development consent must have a sign in a prominent spot on site. It must show the principal certifier's contact details, the principal contractor's name and an after-hours phone number. It must also state that unauthorised entry is prohibited. Keep it up while work is under way and take it down when finished. Building Commission inspectors check these signs.

Building Commission NSW site visits

Building Commission NSW can inspect house sites at any stage, with or without a complaint. It can also demand designs, approvals, certificates and test reports by written notice. Sites are picked by risk and at random. Visits line up with key stages: before a concrete pour, before framing or wet area waterproofing is covered, before stormwater is covered, and after completion but before the occupation certificate.

Inspectors can issue orders to fix defective work, and stop work orders. Orders can also be issued where work could block a valid occupation certificate, or where the principal certifier changes. A company that ignores an order faces up to $330,000, plus $33,000 a day. You can appeal to NCAT (the NSW tribunal) within 30 days, but the order still applies unless NCAT says otherwise. Orders go on a public register.

Keep your records ready

Keep trade certificates, test reports and product details in one place from day one. Your certifier needs them for the occupation certificate, and the Commission can ask for them. A file ready for an audit is usually ready for handover.

Further reform is on the way. NSW's new Building (Approvals and Practitioners) Act 2026 has been passed by Parliament. Under it, construction certificates become "building approvals" and occupation certificates become "completion approvals". Most of it commences later, on a date not yet fixed. The current process applies until then.

Your details go to council before work

When a private certifier is the principal certifier on residential building work, it has to send the council written notice of who is building before work goes ahead. That notice names the principal contractor, gives their licence number and names the home building compensation insurer. On an owner-builder job, it gives the owner-builder's name and, where one is needed, the permit number.

If any of those details become wrong, for example a new builder takes over or the insurer changes, work has to stop until the principal certifier sends the council an updated notice. Let the certifier know about a change on the day it happens.

Where the job must carry home building compensation insurance, the policy has to be in force before work starts. NSW consumer guidance also says the builder must hand the owner evidence of that cover before starting, and before taking any money, deposit included.

Calling up each inspection

For Class 1 and Class 10 buildings, the regulation sets out the critical stages. They fall after digging and ahead of the footings, ahead of any reinforced concrete cast on site, before framework is covered, before wet area waterproofing is covered, before stormwater connections are covered, and when the job is finished. The principal certifier lodges a notice on the NSW Planning Portal listing the inspections your job needs.

The principal contractor, or an owner-builder, has to give the principal certifier at least 48 hours' notice before each critical stage or other required inspection. Another certifier can carry out an inspection if the principal certifier agrees, but the final one must be done by the principal certifier.

Build those 48 hours into the program for every pour and every lining crew. A concreter booked for the morning after a call-up leaves no slack if something needs fixing first.

What if an inspection gets missed?

If anyone other than the principal certifier realises an inspection was missed, they must tell the principal certifier within 2 days. The certifier then has 2 days to tell whoever appointed them, the principal contractor and any owner-builder.

The certifier can log the missed stage as not required only where the miss was unavoidable and the certifier is satisfied the work itself is acceptable. That relief never covers the final inspection. An occupation certificate cannot be issued until the certifier is satisfied every required inspection took place, so a covered stage can mean opening up finished work.

When the certifier issues a direction

A formal written direction about non-compliant work must be on the approved form and issued within 2 business days after the certifier becomes aware of the problem. It explains the defect to be put right and the period allowed for it.

Once that time has passed, the principal certifier inspects the site again, records what was found and gives a copy to the person responsible. If the direction has still not been followed, a notice saying so must be given to the owner of the land, including an owners corporation where there is one.

Reply to a direction in writing, with photos and any certificates that show the fix. A clear trail helps at the occupation certificate stage and in any later audit.

Contract terms that touch certification

For residential work over $5,000 that needs a certifier, the contract must include terms about the owner's freedom to pick their own certifier, unless the owner is a developer. That is why a builder can suggest a certifier but cannot make the choice for the client.

Statutory warranties run alongside the certificates. Builders warrant that the work is fit for purpose and carried out diligently, using suitable materials that are new unless agreed otherwise. Owners have 6 years to start proceedings for major defects and 2 years for other defects, with an extra 6 months where a defect only shows up late in either period. An occupation certificate does not end those duties.