Most renovation blowouts don’t start with the renovation. They start with something found after demolition begins – a wall that turns out to be load-bearing, a sheeting material that needs a licensed contractor, a switchboard that can’t carry the new kitchen. Every one of those is cheaper to deal with before the trades arrive than after.
Here’s the prep work worth doing first.
Pin down when the house was built
The build era tells you more about your renovation budget than the floor plan does. A weatherboard cottage from the 1920s, a fibro home from the 1960s and a brick veneer from the 1980s each carry a different set of problems, and they’re predictable enough that you can plan for them.
Check the certificate of title, old council records or the property’s sale history. If you can find records of previous renovations, note their dates too – a 1975 house with a 1985 extension has two sets of materials and two sets of standards in it.
Once you know the era, you know what to test for.
Test for hazardous materials before anything is disturbed
Asbestos was used in Australian residential construction until the late 1980s, with a total ban on manufacture and use taking effect on 31 December 2003. As a rule of thumb, anything built or renovated before 1990 may contain it. It turns up in external fibro sheeting, eaves, wet-area wall linings, vinyl floor tiles and the backing under them, fences, and the flue and insulation around old heaters.
Undisturbed and in sound condition, it’s generally not the immediate problem. Cutting, drilling or demolishing it is. That’s why testing comes before demolition, not during it: samples go to a NATA-accredited laboratory, and the result determines who can legally do the work. In most states and territories, an unlicensed person can remove only a small area of non-friable material, and friable asbestos requires a licensed contractor in every case.
If your samples come back positive, book Asbestos Removal with a licensed operator like Alpha Asbestos and get the clearance certificate before other trades are scheduled on site.
While the tester is there, ask about lead paint. Houses painted before 1970 often have it under later coats, and sanding is what releases it.
Find out which walls you can actually remove
Open-plan is the most common request in older homes and the one most likely to be quoted wrong. Interior walls in older builds frequently carry roof load, and in some cases carry it in ways that aren’t obvious from the ceiling line.
Get a structural engineer to assess it before you commit to a layout. You’ll pay a few hundred dollars for a report that tells you the beam size, the support required at each end, and whether the footings underneath can take the point load. That report is also what your builder needs to quote accurately and what council or your certifier will want to see.
Do this before you spend money on design work. There’s no sense drawing a kitchen around a wall that has to stay.
Check the services you can’t see
Older homes were wired and plumbed for a fraction of the load a modern house puts on them.
1. Wiring
Rubber or cloth-insulated cabling from before the 1960s is at end of life and often has no earth. If you’re opening walls anyway, rewiring is far cheaper now than later.
2. Switchboard
Count the circuits you’re adding. An induction cooktop, oven, ducted air conditioning and a car charger will exceed what an old board can carry, and an upgrade sometimes involves the network provider, which takes time.
3. Plumbing
Galvanised steel supply pipes corrode internally and restrict flow. Old cast iron or earthenware sewer lines are worth having camera-inspected before you add a bathroom to the line.
None of this is visible in a walkthrough, which is exactly why it becomes a variation halfway through the job.
Plan where the waste goes before demolition starts
Strip-out generates far more volume than people expect. A single bathroom can fill a six-cubic-metre skip once tiles, screed, cabinetry and plasterboard are out, and demolition waste is heavy – tile and masonry hit weight limits well before they fill a bin.
Two things to organise in advance. First, placement: if the bin needs to sit on the footpath or nature strip rather than your property, most councils require a permit, and they’re not always issued same-day. Second, sorting: separated loads of clean timber, metal and masonry cost less to dispose of than mixed loads, so it’s worth arranging a junk removal service that can handle segregated bins or staged pick-ups across the demolition phase.
Asbestos waste is a separate stream entirely. It can’t go in a general skip, and your licensed removalist handles its transport and disposal to an approved facility as part of their scope. Confirm that’s included in the quote.
Sort the approvals before you sort the tiles
What needs approval varies by state and by council, but the pattern is consistent: cosmetic work generally doesn’t, and anything structural, external or involving wet areas generally does. Some work can go through as a complying development with a private certifier, which is faster than a full development application.
Three things catch people out. Heritage overlays and conservation areas restrict what you can change externally, sometimes down to window profiles and paint colours. Strata schemes require owners corporation approval for anything touching common property, including waterproofing membranes and floor coverings above other units. And bushfire-prone land brings construction standards that affect material choices.
Check all three before design work is finalised.
Sequence the trades and build in contingency
Order of operations decides how long the job runs. Hazardous material clearance comes first, then demolition, then structural work, then rough-in for electrical and plumbing, then waterproofing, then linings and finishes. Trades booked out of sequence will either wait or work around each other, and both cost you.
Order long-lead items early. Custom joinery, stone benchtops, imported tiles and some appliances run four to twelve weeks, and the tiler can’t start without the tiles.
Hold 15 to 20 per cent of your budget as contingency. In an older home it’s not padding – it’s the line item that covers what the walls were hiding.
Where this leaves you
Most of this prep costs a few thousand dollars: testing, an engineer’s report, a camera inspection, approvals. Against a renovation budget it’s small, and it converts the expensive category of unknowns into known quantities you can quote, schedule and plan around before the first wall comes down.
