Unapproved Renovations and Extensions in NSW: What Sydney Buyers Should Check Before Buying

If a Sydney property has been beautifully renovated, don’t assume every alteration has been approved.

Extensions, enclosed patios, converted garages, studios, decks, attic conversions and some internal changes can require investigation. In NSW, some minor works may be exempt development, while other work may need a Complying Development Certificate (CDC) or Development Application (DA), depending on the work and the property.

For buyers, the issue is not simply whether a renovation looks good.

You need to understand what you are actually buying, whether there are approval or compliance issues, and whether those issues could affect your finance, insurance, future renovation plans or negotiation position.

Quick Answer

Before buying a renovated property in NSW:

1. Ask for the approvals and supporting documents.
2. Check council and planning records.
3. Compare the approved plans with the property as it exists today.
4. Have your solicitor or conveyancer investigate any legal or contract implications.
5. Obtain appropriate building, planning or engineering advice where necessary.
6. Consider the potential effect on finance and insurance.
7. Factor any uncertainty or rectification cost into your offer.
8. If the risk is unacceptable, be prepared to walk away.

What Counts as an Unapproved Renovation?

The phrase “unapproved renovation” can cover several different situations.

A previous owner may have completed work without obtaining an approval that was required.

Alternatively, work may have been approved but built differently from the approved plans.

Examples that may deserve investigation include:

• Rear extensions
• Enclosed alfresco areas or patios
• Converted garages
• Converted attics
• Studios or additional rooms
• Decks or balconies
• Structural wall changes
• Relocated kitchens or bathrooms
• New windows or external alterations
• Secondary dwellings or granny flats
• Changes to the internal layout
• Building work that appears substantially different from approved plans

Not every renovation requires a DA.

Some minor work may qualify as exempt development, while other work may qualify as complying development if it meets the required standards. That is why buyers should not simply rely on someone saying, “It didn’t need approval.”

1. Ask the Selling Agent for the Paperwork

Start with a simple question:

“Do you have the approvals and plans for the renovation or extension?”

Depending on the work, relevant documents may include:

• Development consent
• Complying Development Certificate
• Construction Certificate
• Occupation Certificate
• Approved architectural plans
• Building certificates or other council documentation
• Engineering or certification documents
• Strata approval where applicable

Don’t assume a renovation is approved simply because the selling agent says the previous owner had it professionally completed.

Ask for the actual documentation.

2. Check Council and Planning Records

The next step is comparing the property’s current condition with the records available for the property.

NSW has different approval pathways, including exempt development, complying development and development applications. A renovation may have followed one of these pathways depending on the circumstances.

This becomes particularly important when a property has been substantially altered.

Imagine you inspect a three-bedroom house that appears to have:

• A large rear extension
• An enclosed outdoor area
• A converted garage
• An additional bathroom

The property may look fantastic.

But if the documentation doesn’t line up with what exists, you have a due-diligence issue.

3. Compare the Plans With the Property

This is one of the most important checks.

Don’t only ask whether an approval exists.

Ask whether the property was actually built in accordance with the approval.

Look at:

• Number of rooms
• Extension dimensions
• Walls and openings
• Windows and doors
• Bathrooms
• Kitchens
• Garage arrangements
• Outdoor structures
• Additional rooms
• Roof changes
• Converted areas

A property can have historical approval documents and still require further investigation if the current building differs materially from those documents.

4. What If the Work Was Never Approved?

This is where buyers need to slow down.

Don’t automatically assume the property is worthless.

But don’t ignore the issue either.

The appropriate response depends on what the work is, when it was completed, what approvals were required, the property’s planning controls, construction and the advice of the relevant professionals.

Your solicitor or conveyancer can advise on the legal and contractual implications.

A building professional, certifier, engineer or planner may also need to inspect or assess the work.

5. What Is a Building Information Certificate?

You may come across the term Building Information Certificate, or BIC.

A BIC is a formal council certificate that can provide protection from certain council enforcement action relating to the building or part of the building covered by the certificate. It is commonly used in property transactions and where unauthorised building work needs to be investigated.

But there is an important distinction:

A Building Information Certificate is not simply retrospective approval of the renovation.

NSW council guidance specifically notes that a BIC does not retrospectively approve unauthorised building work and is not an Occupation Certificate.

A BIC application also doesn’t guarantee that a certificate will be issued. Council may require further information, inspections or works, and in some circumstances enforcement action can still arise.

So if a seller tells you:

“Don’t worry — we’ll just get a BIC.”

That should not be treated as the end of your due diligence.

6. Think About Your Future Plans

An unapproved structure can become particularly important if you intend to renovate again.

You might buy a property thinking:

“Once we move in, we’ll extend this further.”

But existing planning, building or approval issues may complicate your plans.

Before purchasing, consider:

• What you want to change
• Whether the existing structure is authorised
• Whether existing work complies with relevant requirements
• Whether future development is permitted
• Heritage or conservation controls
• Site constraints
• Easements
• Flood or bushfire considerations
• Whether further professional advice is required

Don’t buy based solely on what you hope to do with the property.

7. Could It Affect Your Home Loan?

This is another reason to investigate before committing.

A lender’s assessment can depend on the individual property, valuation, lender policy and circumstances of the application.

If a property has unusual construction, additional accommodation, an apparent unapproved extension or other issues, it may be worth raising the matter with your mortgage broker and lender before becoming committed.

The important point is simple:

Don’t discover a property problem after you’ve already committed to buying it.

8. What About Insurance?

Insurance should also be considered.

Don’t assume every existing structure or alteration will automatically be treated the same way by an insurer.

Ask the relevant insurer or insurance professional about the specific property and circumstances.

This is particularly important where the property includes unusual structures, converted areas, extensions or other work that doesn’t clearly match the available documentation.

9. Use the Issue in Your Negotiation

Finding an approval issue doesn’t necessarily mean you have to walk away.

Sometimes it simply means you need more information.

Other times, the issue may justify a different price or additional conditions, depending on the circumstances and legal advice.

You may need to allow for:

• Building reports
• Engineering advice
• Planning advice
• Rectification
• Certification
• Future approval costs
• Additional time
• Finance uncertainty

That information should form part of your overall assessment of what the property is worth to you.

10. Know When to Walk Away

This is often the hardest part for buyers.

You’ve inspected the property.

You love the kitchen.

The backyard is perfect.

The location is exactly where you wanted.

And then you discover an approval problem.

It’s easy to think:

“Surely we can sort it out later.”

Sometimes you can.

Sometimes the risk, cost or uncertainty simply isn’t worth it.

A good buying strategy includes knowing your walk-away point before emotion takes over.

Common Mistakes Buyers Make

Mistake 1: Assuming Renovated Means Approved

A professional-looking renovation is not proof of approval.

Mistake 2: Relying Only on the Selling Agent

The selling agent can provide information, but important legal, planning and building questions should be checked through the appropriate professionals and authorities.

Mistake 3: Only Checking Whether a DA Exists

Not every form of development follows a DA pathway. Some work may be exempt or may have been approved through a CDC.

Mistake 4: Assuming a BIC Fixes Everything

It doesn’t.

A BIC is not retrospective approval and is not an Occupation Certificate.

Mistake 5: Waiting Until After Settlement

If the issue matters to your decision, investigate it before you commit rather than hoping it will be easy to resolve later.

NSW Buyer Checklist

Before making an offer on a substantially renovated property, ask:

Property

• What has been changed?
• What has been added?
• Are there converted areas?
• Are there additional rooms or bathrooms?

Approvals

• Was the work exempt?
• Was a CDC issued?
• Was a DA required?
• Is there a Construction Certificate?
• Is there an Occupation Certificate where relevant?
• Do the plans match the property?

Legal

• Has my solicitor or conveyancer reviewed the issue?
• Does the contract disclose anything relevant?
• Are there restrictions, easements or other title issues?

Building

• Does the work appear structurally sound?
• Is specialist inspection required?
• Are there signs of defective or incomplete work?

Finance

• Is the property acceptable to my intended lender?
• Could the issue affect valuation or borrowing?
• Do I need to disclose anything to the lender?

Insurance

• Will the insurer cover the property and its existing structures?
• Are there specific conditions or exclusions?

Negotiation

• Does the issue change what I’m prepared to pay?
• Do I need further reports before making an offer?
• What is my walk-away price?

How a Buyers Agent Can Help

A buyers agent doesn’t replace your solicitor, conveyancer, building inspector, engineer, planner, certifier, insurer or mortgage lender.

But a buyers agent can help identify questions that need to be investigated before you commit.

At Truth Group, the property assessment process can include looking at:

• Property condition
• Comparable sales
• Renovation history
• Planning considerations
• Potential red flags
• Due-diligence requirements
• Offer strategy
• Negotiation position

Where specialist advice is required, the right approach is to involve the appropriately qualified professional.

The goal isn’t to find a reason to reject every property.

It’s to understand the property well enough to make a disciplined decision.

Final Takeaway

A renovated property can be a great purchase.

But the renovation itself should never be the reason you skip due diligence.

Before buying in Sydney or anywhere in NSW, check what work was done, what approvals were required, whether the documentation matches the property, and whether the issue could affect your legal position, finance, insurance or future plans.

If something doesn’t add up, stop and investigate before you commit.

If you’ve found a Sydney property with an extension, converted garage, enclosed patio, studio, granny flat or other renovation that raises questions, Truth Group can help you assess the property, comparable sales and negotiation strategy while working alongside the relevant legal and specialist professionals.

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Frequently Asked Questions

Do all renovations in NSW need council approval?

No. Some minor works may qualify as exempt development, while other work may qualify as complying development or require a development application. The exact requirements depend on the work and the property.

Can I buy a property with unapproved renovations?

You may be able to, but the specific circumstances should be investigated before you commit. Obtain appropriate legal, planning and building advice.

Does a Building Information Certificate approve an unapproved renovation?

No. A BIC can provide protection from certain council enforcement action, but it does not retrospectively approve unauthorised work and is not an Occupation Certificate.

Can unapproved renovations affect a mortgage?

They can raise questions depending on the property, lender, valuation and circumstances. Discuss the property with your mortgage broker and lender before committing if there is a material concern.

Should I walk away from a property with unapproved work?

Not automatically. Some issues may be manageable; others may create too much risk or cost. The decision should be based on the specific property and advice from the appropriate professionals.

Who should check whether a renovation is approved?

Depending on the issue, this may involve the local council, NSW Planning Portal records, your solicitor or conveyancer, building inspector, certifier, engineer, planner or another qualified professional.

Important: This article is general information only and is not legal, planning, building, insurance or financial advice. Requirements can vary by property and circumstances. Obtain appropriate professional advice before purchasing.