Guide
Unauthorised and undocumented building work
Usually discovered at the worst possible moment — a sale, a purchaser's solicitor, or a letter from council.
The situation, and why it's more common than it sounds
An extension with no consent. A granny flat someone built in the eighties. A deck that was approved but built differently. A carport nobody ever mentioned. Work that had consent but never got an occupation certificate, so nothing closes out.
None of this is unusual, and most of it sits quietly for years. It surfaces when someone looks: a purchaser's solicitor comparing the survey to the approvals, a bank valuer, a neighbour who complains, or a council officer driving past.
At that point there are four possible routes, and they are not mutually exclusive.
The distinction that matters most
A building information certificate, under Division 6.7 of the Act, regularises the building's status. Once issued, it restricts council from making an order or taking proceedings to have the building demolished, altered or rebuilt — to the extent of the certificate — for seven years.
It does not retrospectively grant development consent. Where the work needed consent and never had it, a retrospective development application may be required as well, and on many jobs the answer is both.
Getting this wrong wastes money in a specific way: people pay for a certificate expecting it to resolve a planning problem it was never designed to resolve.
Two gates, before anything else is worth doing
Is it permissible? Development prohibited in the zone cannot be regularised by a certificate. If what was built could never have been approved, no amount of documentation fixes it and the honest answer is removal or partial demolition. This gets checked first because everything else is wasted effort if it fails.
Can it be certified? A BIC application generally needs certification of structural adequacy and a BCA assessment. Work built without approval was frequently built without engineering, and footings, framing, waterproofing and drainage are where it comes apart. Where it can't be certified as built, the sequence becomes rectify, then certify — and knowing that at the start is the difference between a plan and a nasty surprise.
If you're selling
This is the most common trigger, and the most time-pressured. A certificate takes time that a settlement date often doesn't allow, so the practical question becomes what can be started now, what has to be disclosed, and how the risk gets allocated between the parties.
That is a conversation for your solicitor as much as for us. What we can do quickly is tell you what the works actually are, whether they're capable of being regularised, and what the route looks like — which is usually the information the negotiation is missing.
Where to go next
- Building information certificates — the four routes in full, and what the application needs
- Development applications — if a retrospective DA is required
- Renovating and extending — getting the next one approved properly
General information, not legal advice. Where an order or proceedings are on foot, get legal advice as well as planning advice.
Common questions
What happens if I built something without approval?
Council has a range of options and may use more than one: take no action, invite a development application, issue a penalty notice, issue an order, or accept an application for a building information certificate. Which is realistic depends largely on whether the work could have been approved and whether council has already acted.
Does a building information certificate make the work legal?
It regularises the building’s status, not its planning approval. Once issued, council is restricted from ordering demolition, alteration or rebuilding to the extent of the certificate for seven years. It does not retrospectively grant development consent — where the work needed consent, a retrospective development application may also be required.
Can any unapproved work be regularised?
No. Development that is prohibited in the zone cannot be fixed by a certificate. And work that cannot be certified as structurally adequate or BCA-compliant has to be rectified first, which sometimes means partial demolition.
What does a BIC application need?
The council’s form and fee, as-built plans of what is actually there, a structural engineer’s certification of structural adequacy, a BCA compliance assessment, a survey where boundaries or setbacks are in question, and fire safety documentation where the building type requires it.
The work was done decades ago — does that help?
It can. Older work is sometimes lawful because it predated the instrument that would now prohibit it, and council records, historic section 10.7 certificates and dated aerial photography can establish that. Age alone is not a defence, but it is often the beginning of an evidence trail.
Council has sent me a letter. What should I do?
Do not ignore it and do not answer it off the cuff — what you write becomes part of the record. Get the notice reviewed so you know what it actually requires and which routes remain open. Where an order or proceedings are on foot, get legal advice as well as planning advice.
General information about NSW planning, current at September 2026. Not advice on a particular site — the instruments are amended often and councils vary them locally.
Have works with no paperwork?
Send us the address and what's there. We'll tell you which route applies before you talk to council.