Unapproved Structures Found During Due Diligence

It is more common than most buyers expect to find that a structure on a property, a deck, a carport, a garden shed, a pergola or even a granny flat, was built without the council approval it needed. Sometimes the owner genuinely did not know a permit was required for that particular type of work. Sometimes approval was applied for but never finalised. Occasionally the work was simply never lodged at all. Whatever the cause, discovering this during due diligence raises a practical question: does it affect the purchase, and if so, what can actually be done about it.

How This Usually Comes to Light

Unapproved structures are typically identified in one of two ways. A buyer's solicitor or conveyancer orders a council or planning search as part of standard due diligence and finds no record of approval for a visible structure, or a building inspector notes something during a pre-purchase inspection that does not match what the plans show. Sometimes it only becomes apparent when a title search or survey reveals a structure sitting partly over a boundary or easement, which raises its own separate issues around encroachment. Either way, the earlier it is picked up, the more options both parties have to deal with it sensibly.

Why It Matters to a Buyer

Once you settle on a property, you generally inherit responsibility for anything unapproved on it, even if you had nothing to do with building it. A local council can, in principle, require unauthorised work to be brought up to standard or removed, regardless of who built it. In practice, councils typically pursue this when there is a complaint, a safety concern, or the issue surfaces through an unrelated planning matter, rather than actively hunting down every unapproved shed in a municipality. Even so, buying a property with a known compliance gap is a decision worth making with full information, not one to discover after settlement.

What Options Exist Once It Is Found

Depending on the type of structure and how serious the non-compliance is, there are generally a few paths forward. The seller may be able to obtain retrospective approval before settlement, sometimes through a specific certification process designed for exactly this situation. Western Australia's building regulator, for example, sets out formal pathways for retrospective approval of unauthorised work through its Building and Energy division, as outlined on the WA Government's building approvals guidance. Other states run comparable, though differently named, processes. Where retrospective approval is not realistic before settlement, a special condition can instead make the buyer's obligation to proceed dependent on the issue being resolved, or on a price adjustment to reflect the cost and risk of fixing it themselves.

When It Is Genuinely Minor

Not every unapproved structure is a serious problem. Many councils exempt small, low-risk items such as garden sheds under a certain size, low retaining walls, or basic fencing from needing approval at all, so the first step is confirming whether approval was actually required in the first place. A conveyancer working through this with your local council or a private certifier can usually establish fairly quickly whether you are dealing with a genuine compliance gap or simply a structure that never needed a permit to begin with.

When It Is More Serious

Larger unapproved structures, particularly habitable additions like a converted garage or an unapproved granny flat, carry more risk. These can affect insurance, future renovation plans, and resale value down the track, since a subsequent buyer's due diligence will likely uncover the same issue. Home and contents insurers may also decline or limit cover for damage connected to unapproved work, which is worth checking before you rely on a policy covering a structure that was never signed off. This is closely related to the kind of gap covered in our guide to missing compliance certificates found before settlement, since an unapproved structure and a missing certificate often go hand in hand.

What a Buyer Should Do

If due diligence turns up an unapproved structure, resist the urge to either panic or ignore it. Ask your conveyancer to confirm exactly what approval should have existed, what the council's likely position is, and what realistic options are available before you are committed to settlement. This is one of the clearer reasons to build a due diligence or building inspection condition into a residential purchase contract rather than relying on what is visible during an open home.

It is also worth asking the seller directly, through your conveyancer, whether they are aware of any unapproved work on the property and whether they have already made any attempt to have it certified. A seller's honest disclosure at this stage, even an imperfect one, is far more useful than silence, and it often speeds up the process of working out whether the issue is a genuine deal-breaker or simply something to factor into your offer.

How a Conveyancer Helps

A conveyancer's job here is to turn a vague worry into a specific, manageable issue. That means ordering the right searches, liaising with council or a certifier where needed, and drafting special conditions that protect you if the structure cannot be resolved before settlement. For sellers, the same process in reverse, addressing compliance gaps before listing a residential sale, generally leads to a smoother transaction and fewer surprises for everyone involved.