Planning a renovation: the checks before you start
Before a renovation starts, check four things: what approvals the work needs, what hazardous materials you might disturb (asbestos and lead paint in older homes), what the structure and services can actually take, and what your title and planning rules allow you to build. Almost every blown budget and stalled project traces back to one of these being discovered mid-job rather than before it. The cheapest part of a renovation is the homework.
The renovation surprises are nearly all knowable
The stories everyone has heard — the budget that doubled, the project that stalled for months — almost always come down to something found after the work began that could have been found before. Asbestos in the wall that was about to come down. A wall that turned out to be holding up the roof. A switchboard that could not carry the new kitchen. An easement running under the planned extension. None of these are bad luck; they are homework that did not get done. Spending a little time and money up front to find them is the single best thing you can do for a renovation budget.
Approvals: what the work actually needs
Not all work needs a permit, but more does than people expect, and the penalties for unpermitted work surface later — at sale, in a disclosure statement, or when an insurer declines a claim on it. Structural changes, additions, decks, and many wet-area and plumbing changes typically need a building permit; if your property carries a planning overlay — heritage, vegetation, flood — you may also need a planning permit before that. Check what applies before you commit to a design, because an overlay can change what is approvable, not just add a step. Building permits issued in the last seven years are disclosed when a home is sold, so unpermitted work does not stay hidden.
Hazardous materials: know before you disturb
This is the one that turns a cheap job dangerous. Two materials are tied to the age of the home, and both are a problem only when disturbed — which is exactly what a renovation does.
Asbestos
If your home was built or renovated before the mid-1980s, assume it contains asbestos until proven otherwise — in fibro sheeting, eaves, vinyl floor backing, and corrugated roofing. Asbestos was banned nationally on 31 December 2003, but the existing material stays where it is. It is safe left alone; cutting, drilling or demolishing it is what releases the fibres. Have suspect materials identified before any work, and use a licensed removalist for anything beyond the smallest amount — this is not a DIY corner to cut.
Lead paint
Homes painted before the 1970s are very likely to carry lead paint, and ones built before 1997 may still have it under newer coats. Sanding, scraping or heat-stripping old paint releases lead dust, which is a particular risk around young children. Test before you strip, and follow lead-safe methods rather than taking an orbital sander to old weatherboards.
Structure and services: what the building can take
Load-bearing walls and structure
Open-plan dreams meet reality at the load-bearing wall. Removing or opening a wall that carries load needs engineering and a beam, not a sledgehammer and optimism, and getting it wrong is both dangerous and expensive to undo. Before you plan to remove anything, establish what is structural — and if the home already shows movement, read cracks: structural or cosmetic before you add to the load on the footings.
Wiring, plumbing and the switchboard
A new kitchen, bathroom or extension asks more of the services than the original house was built to give. An older switchboard may need upgrading to carry the load and to bring in modern safety switches; original wiring and galvanised plumbing may need replacing as part of the work rather than worked around. It is far cheaper to upgrade services while the walls are already open than to come back and do it later. Knowing the age and state of the services — covered in what your home needs by decade — tells you what to budget for.
Title and planning: what you are allowed to build
The last check is the one people skip because they already own the place: what the title and planning rules actually permit. An easement — often for drainage or sewerage — can run under the exact strip where the extension was going, and you generally cannot build over it without the authority's consent. A restrictive covenant can cap height, materials or the number of dwellings regardless of what the planning scheme allows. And overlays add conditions on top of the zone. These sit in your title documents and the property's planning information — the same ground a buyer reads in a Section 32. Check them before you pay for a design built around something you are not allowed to do.
Build the homework into the budget
Two habits keep renovations on the rails: do the checks above before the design is locked, and carry a real contingency for what opening up an old building still reveals. Even with good homework, older homes hold surprises behind the plaster, so a sensible contingency is part of the plan, not an admission of failure. The better your starting picture of the building, the smaller that contingency needs to be — which is the practical case for knowing your home before you change it.
Frequently asked questions
What should I check before renovating my home?
Four things, before the design is locked: what approvals the work needs, what hazardous materials (asbestos, lead paint) you might disturb in an older home, what the structure and services can take, and what your title and planning rules allow you to build. Most blown budgets trace to one of these being found mid-job.
Do I need a permit to renovate?
Often, yes. Structural changes, additions and many wet-area and plumbing changes usually need a building permit, and a planning overlay may require a planning permit first. Unpermitted work surfaces later — at sale, in disclosure, or in an insurance claim — so confirm what applies with your council or a building surveyor before you start.
How do I know if my home has asbestos before renovating?
If it was built or renovated before the mid-1980s, assume asbestos is present until tested — commonly in fibro sheeting, eaves, vinyl floor backing and roofing. Have suspect materials identified before any work, and use a licensed removalist, because the danger is in disturbing it.
How do I know if a wall is load-bearing?
You don't, reliably, by looking — which is the point. Removing or opening a wall that carries load needs an engineer and a properly sized beam. Establish what is structural before you plan to remove anything, as getting it wrong is dangerous and costly to undo.
Will my switchboard and wiring handle a renovation?
An older home was not wired for a modern kitchen, bathroom or extension. The switchboard may need upgrading to carry the load and add safety switches, and original wiring or plumbing may need replacing as part of the work. It is far cheaper to do while the walls are open than to retrofit later.
Can I build an extension anywhere on my land?
Not necessarily. An easement (often for drainage or sewerage) can prevent building over part of the block, a restrictive covenant can limit height or materials, and overlays add conditions. These sit in your title and planning documents — check them before designing around something you may not be allowed to build.
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