Renovate or rebuild comes down to a handful of questions, asked in order: what does the client want, what does the existing house give them, what is hidden, what will council allow, and what does the site cost to work with. A builder cannot answer the last three from the kerb. That is why the first step is paid site work and not a free quote.
The questions that decide renovate or rebuild
Ask these before you talk about money:
- What is not working in the house now? Layout, light, size, condition or all four?
- What do they want at the end: number of bedrooms, living space, a single storey, a second storey?
- How long do they intend to stay?
- Can they live elsewhere during the build, and for how long?
- What is the ceiling on the budget, not the hope?
- Is there a design or a brief already, or only an idea?
If most of what they want sits inside the existing walls and roof, renovation is usually the starting point. If they want a different footprint, a different height, a new structure under the house, or they are rebuilding most of it anyway, a rebuild enters the conversation.
What the existing structure and site are hiding
This is where renovation quotes go wrong. A house you are keeping carries its history: footings that may not suit what you want to add, old wiring and plumbing, framing that has moved, and materials that need careful handling. A site you are rebuilding on has its own hidden items. New South Wales’ planning portal lists things to check for a knockdown rebuild, including heritage listings, tree preservation orders, excavation and drainage, and what a section 10.7 planning certificate says about zoning, planning controls, flooding and bushfire prone land. It lists asbestos and soil contamination among the hazards to check. It also covers underground services and asbestos, saying licensed professionals must disconnect services before demolition and that removal needs a licensed specialist and a clearance certificate.
The portal’s demolition page adds that a licensed removalist is required for more than 10 square metres of non-friable asbestos in NSW, and that work can resume only after an independent assessor issues a clearance certificate. These are NSW rules. Other states have their own, so ask your state regulator.
Then there is the ground. Whatever you build, the soil and levels decide the footings and the earthworks. See geotechnical reports and feature and contour surveys.
Approvals and timing at a high level
The route depends on state, council and the site. The NSW portal says demolition is usually handled through a demolition permit and a separate development application, or a complying development certificate, and that your council can advise which applies. It also says the existing house cannot be demolished until approval for the new home has been granted. The sequence in your state may differ.
The timing point holds anywhere: approvals take time, they come before you can set a start date, and the client is often paying rent or a mortgage on a house they cannot use. Do not promise dates. Say what the approvals are and who is responsible for each. This is general information, not legal or planning advice: approval rules differ by state and council, so check with the council, your regulator or a solicitor for the job in front of you.
Why neither price is reliable without site checks
Queensland’s building regulator tells owners comparing quotes that the builder must provide a soil test and contour survey, unless the owner already has them, and notes reports of some builders charging excessively for earthworks and footings. Victoria’s regulator tells builders preparing a contract to allow a reasonable cost for the nature and location of the site and to obtain a soil report and check the foundation data.
A quote for a rebuild that skips the site work is a guess about demolition, hazards, earthworks and footings. A quote for a renovation that skips the investigation is a guess about everything behind the walls. We have left cost comparisons out of this article deliberately. Any figure someone gives you before those checks is not a price.
Paid feasibility as the first step
A feasibility stage answers the renovate or rebuild question properly. It can include a site visit and inspection of the existing structure, the survey and soil report, a check of council requirements, a concept and a cost range for each route, and a written recommendation. The client pays for that work and keeps the result.
Paid early work has its own rules in some states. Queensland’s regulator, for example, warns that fees or penalties in a preliminary agreement for a client who does not go ahead may be illegal. How to set the fee and the terms is covered in charging for preliminary work, and our pre-construction page covers how we help builders run this stage.
What to bring to the first meeting
Ask the homeowner to bring these:
- The title or certificate of title, and the address.
- Any existing drawings, surveys, soil reports or approvals for the house.
- Photos of what bothers you and what you want to keep.
- Your budget ceiling and your timing limits.
- Whether you can move out, and for how long.
- Anything you have been told about the house: past repairs, leaks, cracks, asbestos.
Bring your own list of what you will check and what you charge for the first stage, in writing, so the client leaves the meeting knowing the next step. More for this kind of work is on our renovations and extensions page.
Common questions
Is it cheaper to renovate or rebuild?
The house and the site decide it, and we will not give a figure here. The answer comes from site checks and a priced scope for each route.
What is the knockdown rebuild process?
In broad terms: check the site and council requirements, get approval for the new home, arrange demolition, including services and any asbestos, then build. The order and approvals differ by state.
Can I demolish before I have approval for the new house?
In NSW, the planning portal says the existing house cannot be demolished until approval for the new home has been granted. Check your state and council.
What is a knockdown rebuild feasibility study?
Paid early work that checks the site, the existing house, council requirements and rough costs, and gives a written recommendation before any fixed price.