The Real Cost of Cheap Bathroom Renovations
You’ve got a quote in front of you. It’s low — maybe surprisingly low — and part of you knows something doesn’t add up, but you can’t put your finger on exactly what. That instinct is worth listening to.
Cheap bathroom renovations don’t save money. Not reliably. What they do is defer the cost — from today’s invoice to a remediation bill somewhere down the track, once the waterproofing fails and the tiles start lifting and the moisture finds its way into the wall framing. We’ve seen homeowners spend $18,000 fixing a bathroom they paid $7,500 to renovate two years prior.
Here’s what actually happens.
What Rework Actually Costs
Stripping out a failed bathroom and doing it properly the second time costs more — sometimes significantly more — than doing it properly the first time.
Waterproofing failure remediation means pulling every tile in the wet zone. Floor, shower walls, and often the full bathroom depending on how far the water has tracked behind the substrate. Then the screed comes up. Then the membrane. You’re back to bare concrete or timber before anything new goes down. For a standard bathroom, that strip-out and re-waterproofing work runs $8,000–$15,000 before a single new tile is laid. Larger bathrooms or those with extensive sub-surface damage sit toward the top of that range or beyond it.
Retiling is quoted on top of that. Once the waterproofing is fixed and has passed inspection, you’re relaying tiles across the entire wet zone. Figure $3,500–$7,000 for an ensuite. More for a main bathroom, floor-to-ceiling tiling, or any large-format tile work.
Mould remediation is where costs can spiral fast. Surface mould is manageable. But when moisture has been sitting behind tiles for twelve months or more, it’s usually into the plaster. Cutting out and replacing affected plasterboard adds $1,500–$3,000. If it’s reached timber wall studs or migrated to the subfloor, you’re into structural repairs — and the total can push past $20,000.
Then there’s the insurance problem. Many private home insurance policies exclude damage caused by defective workmanship. If the original renovator wasn’t licenced, didn’t hold Home Building Compensation cover, or used non-compliant products, the remediation bill sits entirely with you. No payout, no comeback on the contractor, no manufacturer warranty to call on.
Why the Quote Is That Low
A bathroom renovation has a cost floor. Below that floor, something is being left out. The question is what.
Waterproofing is where corners get cut first, because it’s invisible. A compliant installation under AS 3740 requires the right membrane product, applied at the correct thickness, with cove formation at every wall-floor junction, and enough cure time before tiles go on top. Skip any one of those steps — thinner membrane, no cove, tiling too early — and you’ve saved maybe $600 to $900 on the job. You’ve also built the conditions for a failed bathroom in 18 months.
Unlicensed labour is common in cheap renovations. Waterproofing is a licenced activity in most Australian states. So is the plumbing work that runs alongside it. Cheap operators manage their labour costs by using unqualified workers on tasks that legally require a licenced contractor. The work looks identical on the day. The difference shows later.
Non-compliant products are cheaper because they haven’t been tested to Australian standards. A membrane that’s not certified to AS 3740 carries no verified performance data — and no manufacturer warranty. If it fails, there’s nothing to claim against.
Pre-tile inspections get dropped. A waterproofing inspection before tiles go on creates a paper trail and a checkpoint. Legitimate operators build this into the job timeline. Operators cutting costs tile straight over the waterproofing and move to the next job. Once tiles are down, verification means pulling them up again.
And then there’s insurance. Work over the state threshold requires Home Building Compensation cover before work begins. Operators working outside this — whether deliberately or because they’re not eligible — leave the homeowner with no recourse if something goes wrong.
How a $4,000 Saving Becomes a $20,000 Problem
The frustrating thing about waterproofing failures is how slowly they show themselves.
Month six. Grout cracking at the corner where the shower wall meets the floor. Some slight discolouration on a tile near the base. Easy to dismiss — grout moves, tiles settle. You regrout and forget about it.
A year later. A few tiles near the shower base are lifting slightly at the edges. A tiler comes out to relay them. He mentions the membrane underneath looks off but he’s not certain. The repair costs $1,800. The underlying problem is not fixed.
Year two or three. Water has been tracking behind the wall tiles long enough to soften the adhesive. Tiles are coming loose in the shower. There’s a stain on the ceiling of the room below. A proper inspection confirms the membrane has failed at multiple junctions. Plaster in two wall cavities has mould through it. Full strip-out required. The quote is $14,500.
Year four or five, worst case. Moisture has been in the wall framing long enough to damage the timber. An inspector finds rot in two studs. A section of subfloor needs replacing. The total remediation comes in at $22,000.
The original renovation cost $9,500. The cheapest quote saved $4,000 on that job. None of this is unusual — it’s the pattern. The low quote didn’t make the renovation cheaper. It just changed when the full cost arrived.
What You’re Actually Paying For
When a legitimate bathroom renovation quote comes in at $18,000–$25,000, people sometimes push back on the number. But the question isn’t whether it’s expensive — it’s what’s included.
Compliant waterproofing under AS 3740 is not a premium line item. It’s the baseline. The correct membrane product for the application, applied at the right thickness, with cove formation at all wall-floor and wall-wall junctions, and a mandatory cure period before any tiles go on. That costs money to do correctly, and a licenced waterproofer who stakes their licence on the outcome costs more than a labourer who doesn’t have one.
A pre-tile waterproofing inspection creates a documented record that the work was compliant before it got covered up. In some states this is a council inspection; in others it’s a private certifier. Either way, it’s the only paper trail you have once tiles are laid — and it matters if you ever need to make a warranty or insurance claim.
Home Building Compensation insurance must be in place before work begins on jobs over the state threshold. In NSW that’s $20,000. It protects you if the contractor becomes insolvent, disappears, or dies — and covers defects discovered after the work is done. A contractor who doesn’t raise this is either working below the threshold or isn’t eligible. Worth asking the question directly.
Product warranties on certified membranes run 10–25 years from the manufacturer. Those warranties are void if the product was installed by an unlicensed operator or outside the manufacturer’s specified method. The warranty is only as good as the installation behind it.
Red Flags in Any Renovation Quote
Most people know to get three quotes. Fewer know what to look for in each one. These are the specific signals that should give you pause — or prompt you to ask a direct question before you sign.
⚠ Red Flag
No licence number on the quote
Every licenced contractor should be willing to put their licence number in writing. Absence of it is not an oversight.
⚠ Red Flag
No mention of insurance
Home Building Compensation cover must be in place before work starts. If insurance isn’t raised, raise it yourself.
⚠ Red Flag
Cash only or full payment upfront
Progress payments tied to stages are standard. Demanding the full amount before work begins removes your only financial leverage.
⚠ Red Flag
More than 30% below comparable quotes
A price that’s dramatically lower for the same scope means something is excluded. Ask specifically what — and get the answer in writing.
⚠ Red Flag
No written contract or scope
Verbal agreements leave you with no scope, no variations process, and no comeback. If it’s not in a signed document, it doesn’t exist.
⚠ Red Flag
No mention of waterproofing inspection
A legitimate operator can tell you exactly how the pre-tile inspection happens. Vague or dismissive answers here are information.
⚠ Red Flag
No site visit before quoting
An accurate price requires a site inspection. Quotes given over the phone or via message without seeing the space are not reliable.
⚠ Red Flag
Vague or bundled line items
“Tiles and labour” tells you nothing. Waterproofing, fixtures, waste disposal, and inspection costs should each appear separately.
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How to Compare Quotes Without Getting Burned
Getting three quotes is standard advice. What’s less commonly said is that three quotes for different scopes aren’t comparable — you’re not evaluating price, you’re evaluating what each contractor decided to include.
Before you line up numbers, confirm that each quote covers the same scope. Waterproofing, tiling, fixtures, waste removal, and inspection costs should each be itemised separately. If one quote has a single line — “full bathroom renovation including tiles and labour” — and another breaks out waterproofing with a specific product and membrane spec, those aren’t the same quote.
Verify the licence number. Every state has an online register — NSW Fair Trading, VBA in Victoria, QBCC in Queensland. Put the number in and confirm it’s current, the licence class covers bathroom renovation and waterproofing, and the person named on the quote holds it. This takes three minutes. See our full breakdown of contractor licence requirements by state.
Ask for a Certificate of Currency for Home Building Compensation insurance before you sign. Not a verbal confirmation — the actual document. Legitimate contractors carry it.
Ask how they handle the pre-tile waterproofing inspection. A legitimate operator answers this without hesitation: who inspects, when, and what documentation you receive. Vague or dismissive answers to this question are as informative as a direct answer.
If one quote is significantly cheaper, ask what is excluded and get the response in writing. You are entitled to an itemised breakdown before you commit. The answer — or the refusal to provide one — tells you what you need to know.
All specialists in the Lifestyle Bathrooms network are vetted against these standards before any referral is made. See how we vet renovation specialists.
Frequently Asked Questions
Not automatically. Some renovators genuinely run lean businesses, use efficient crews, and deliver solid work at lower margins. The problem isn’t the low price itself — it’s what’s been excluded to hit it. If a quote is significantly cheaper than others for the same scope, something has been cut. It might be profit margin. It might be the waterproofing inspection. The only way to tell is to ask specifically what each line item covers and verify the licence and insurance independently.
A full strip-out and re-waterproofing on a standard bathroom — not including retiling — typically runs $8,000–$15,000. Add retiling and you’re looking at $12,000–$22,000. If mould has reached the plaster or the wall framing, remediation costs climb further. A bathroom with structural timber damage from prolonged moisture exposure can cost $20,000–$30,000 to fully repair. These aren’t rare outcomes — they’re what happens when waterproofing is installed incorrectly and the problem goes unnoticed for a year or more.
It depends on two things: the type of insurance and whether the original work was compliant. Private home insurance policies typically exclude damage caused by defective workmanship — so if the renovator cut corners, the insurer may decline the claim. Home Building Compensation insurance only applies if the contractor was registered and held cover before work began, and if the work met NCC and AS 3740 requirements. See our page on HBC insurance cover for detail on when and how it applies.
In NSW, a contractor carrying out bathroom renovation work must hold a current contractor licence through NSW Fair Trading — either a building licence or a specialist licence covering waterproofing. Plumbing work requires a separate plumbing licence. In the ACT, bathroom renovators must be licenced through Access Canberra. Waterproofing is a licenced activity in both jurisdictions. Our contractor licensing page covers requirements state by state.
Compare against current market rates for your area: a standard bathroom renovation in Sydney or Canberra runs $15,000–$25,000; a premium bathroom with high-end finishes sits $25,000–$45,000+. If a quote is more than 30–35% below the others for what appears to be the same scope, that gap needs explaining. Ask for an itemised breakdown and check specifically whether waterproofing, the pre-tile inspection, licensed labour, and Home Building Compensation insurance are included. If any of those are missing, you have your answer.
For a standard full bathroom renovation — strip-out, waterproofing, tiling, fixtures, plumbing — expect $15,000–$25,000 in most capital cities. Ensuites typically run $12,000–$20,000 depending on size and finish. High-end renovations with large-format tiles, custom joinery, or high-specification fixtures sit $25,000–$45,000 and up. These ranges assume licenced trades, compliant waterproofing, proper inspection, and a written contract. Any quote significantly below these figures for the same scope warrants a detailed conversation about what’s excluded.