As of October 2026, bathroom waterproofing in Sydney costs about $40 to $92 per m², with about $63 typical, according to What’s The Damage. As a whole job, it puts waterproofing in a Sydney bathroom renovation at about $805 to $4,025. National figures from Yellow Pages (2026) are lower, at about $50 to $85 per m² or $900 to $1,800 for a 6 to 10 m² bathroom. In NSW, waterproofing work over $5,000 including GST needs a licensed contractor.
- Sydney wet-area waterproofing costs about $40 to $92 per m², typically $63 (What’s The Damage, October 2026).
- As part of a Sydney bathroom renovation, waterproofing typically costs about $805 to $4,025 for the whole room.
- Small bathrooms cost more per m², because certified waterproofing is priced as a fixed job.
- In NSW, waterproofing worth more than $5,000 including GST needs a contractor licence; it is not licensed at any value.
- Ask for a written certificate naming the installer, licence number, membrane product and AS 3740 before tiles go on.
How much does bathroom waterproofing cost in Sydney?
As of October 2026, Sydney bathroom waterproofing costs about $40 to $92 per m², with $63 typical, according to What’s The Damage’s Sydney tiling guide, which includes GST. National guides are a little lower: What’s The Damage’s Australian guide gives $35 to $80 per m², and Yellow Pages (2026) gives $50 to $85 per m².
Most waterproofers price a bathroom as a whole job rather than strictly per square metre. The table shows the published whole-job ranges.
| Job | Typical range | Source and area |
|---|---|---|
| Wet-area waterproofing, per m² | $40 to $92 (typical $63) | What’s The Damage, Sydney |
| Waterproofing in a full bathroom renovation | $805 to $4,025 | What’s The Damage, Sydney |
| Example: 3.2 m² apartment bathroom | About $2,075 | What’s The Damage, Sydney worked example |
| Small bathroom (up to 5 m²) | $550 to $900 | Yellow Pages, national |
| Medium bathroom (6 to 10 m²) | $900 to $1,800 | Yellow Pages, national |
| Large bathroom (8 to 12 m²) | $2,000 to $4,500 | Yellow Pages, national |
| Shower only | $500 to $1,200 | Yellow Pages, national |
| Bathroom and laundry combined (10 to 15 m²) | $3,000 to $5,500 | Yellow Pages, national |
Indicative only, not quotes. Sydney figures are from What’s The Damage (October 2026); national figures are from Yellow Pages (2026). The Sydney figures run higher, and the sources do not agree exactly.
Why does waterproofing a small bathroom cost so much per m²?
Because the work is mostly fixed, not area-based. What’s The Damage notes that certified waterproofing to AS 3740 costs much the same whether the floor is 3 m² or 8 m².
The waterproofer still has to prime the surfaces, treat every corner, joint and pipe penetration, apply at least two coats, wait for drying between coats and come back to check the work. In a small room, those fixed steps are spread over fewer square metres, so the rate per m² looks high.
What should a waterproofing quote include?
A good quote lists the preparation, the membrane system and the paperwork, not just a total.
- Surface preparation and primer.
- Treatment of wall-to-floor and wall-to-wall junctions. The NCC Housing Provisions require bond breakers at these junctions and at movement joints.
- Sealing around pipe penetrations and the floor waste.
- The membrane product, the number of coats and the minimum thickness from its data sheet.
- Waterstops at the shower edge and doorway where needed.
- A flood test, if you or your strata scheme want one, and how long it will run.
- A written waterproofing certificate.
Items that are often extra:
- Removing old tiles: about $23 to $63 per m² in Sydney (What’s The Damage).
- Floor levelling or preparation: about $17 to $57 per m² in Sydney (What’s The Damage).
- Repairs to damaged walls, floors or framing: Yellow Pages says fixing substructures can add about $500 to $2,000.
- Screeding and re-tiling, which are usually separate trades.
What does AS 3740 require in a bathroom?
AS 3740 is the Australian Standard for waterproofing domestic wet areas, and the current edition is AS 3740:2021. The NCC 2022 Housing Provisions Part 10.2 lets builders follow either its own wet-area rules or AS 3740. Both cover the same basics:
- Shower area: the floor must be waterproof, including any hob or step-down, and the walls waterproof to at least 1,800 mm above the floor substrate.
- Shower wall junctions: waterproof at least 40 mm either side of the joint.
- Floor outside the shower: water resistant on concrete or fibre-cement floors, but waterproof on timber-based floors such as plywood or particleboard.
- Floor falls to a floor waste: between 1:80 and 1:50.
- Membranes must comply with AS/NZS 4858.
Older terraces and upstairs bathrooms on timber floors often need more waterproofing than a ground-floor bathroom on a slab, which can lift the price.
Who can do waterproofing in NSW, and what licence do they need?
In NSW, you need a contractor licence for residential waterproofing worth more than $5,000 in labour and materials, including GST. The licence can be held by an individual, a company or a partnership, and a qualified supervisor certificate is also available. Qualifications include the Certificate III in Construction Waterproofing (CPC31420).
A wall and floor tiling licence also covers waterproofing wet areas to get them ready for tiling, according to the NSW Government. So your tiler may be licensed to do the membrane too. Check the licence class on Verify NSW.
The $5,000 threshold decides when a licence is legally required. It does not mean small waterproofing jobs are low risk. On any job, ask who will apply the membrane, check their waterproofing or tiling licence on Verify NSW, and do not let tiling start before the membrane has dried for the time on its data sheet.
Do you get a waterproofing certificate in NSW?
Ask for one on every job. Strata schemes commonly require a copy of the waterproofing certificate as a condition of approving a bathroom renovation, according to What’s The Damage, and buyers or insurers may ask for it later.
We could not find a single NSW Government form for a waterproofing certificate. A useful certificate should show:
- The installer’s name, business and licence number.
- The property address and the areas waterproofed.
- The membrane product used.
- The standard followed, such as AS 3740 or the NCC Housing Provisions.
- The date of completion, and any flood test result.
Ask for photos of the membrane before tiling as well. If waterproofing fails, NSW statutory warranties apply: the Building Commission NSW lists waterproofing as an example of a major defect, which carries a 6-year warranty from completion.
Does re-waterproofing an existing bathroom cost more?
Usually, yes, because the old finishes have to come off first. In a new or fully stripped room, the waterproofer starts on clean, prepared surfaces. In an existing bathroom, someone has to remove the tiles, take out damaged sheeting or screed and fix any rot before the membrane can go on.
- Yellow Pages (2026) puts waterproofing restoration and leak fixing at about $800 to $1,200, and says repairing damaged substructures can add about $500 to $2,000.
- Tile removal in Sydney adds about $23 to $63 per m² (What’s The Damage).
- Re-tiling is then a separate cost. Sydney bathroom tiling runs about $3,225 to $8,600 supplied and installed for a standard room, excluding waterproofing (What’s The Damage).
If only the shower leaks, a shower-only strip and re-waterproof can cost less than the whole room. Ask the waterproofer to explain what they found and why they recommend the extent of work they have quoted.
Questions to ask your waterproofer
- Which membrane will you use, and can I see its data sheet?
- How many coats, what thickness, and how long will you wait before tiling?
- How will you treat corners, junctions, pipes and the floor waste?
- Will you flood test the floor, and for how long?
- What licence do you hold, and will you give me a written certificate and photos?
- What warranty do you offer on the waterproofing, in addition to the statutory warranty?
What pushes waterproofing prices up?
- Bathroom size and the number of junctions and penetrations.
- Timber or upstairs floors that must be fully waterproofed.
- Damaged substrates that need repair before the membrane goes on.
- Old tiles to remove and dispose of.
- Apartment access, lift bookings and strata work hours.
- Urgent or emergency call-outs, which Yellow Pages says cost more.
NSW rules for the rest of the job:
- Contract: jobs over $5,000 including GST need a written contract. Jobs over $20,000 need a more detailed contract and give you a cooling-off period of five clear business days.
- Deposit: the most you can be asked to pay as a deposit is 10 per cent of the contract price.
- Insurance: for work over $20,000, the contractor must give you a Home Building Compensation (HBC) certificate before taking any money.
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Frequently asked questions
How much does it cost to waterproof a shower only?
Yellow Pages (2026) puts shower-only waterproofing at about $500 to $1,200 nationally. That usually assumes the old tiles are already off. Sydney prices tend to run higher, and removing tiles, fixing damaged walls and re-tiling are extra. If the shower is leaking, read our guide Leaking Shower Repair Sydney before choosing a fix.
Is waterproofing included in a bathroom renovation quote?
It should be, but check. A full renovation quote should name who installs the membrane, which product is used and whether a certificate is provided. What’s The Damage puts waterproofing at about $805 to $4,025 of a Sydney bathroom renovation. A quote that does not mention waterproofing at all is a warning sign.
Do tilers do waterproofing in NSW?
Many do. The NSW Government says a wall and floor tiling licence covers waterproofing wet areas to get them ready for tiling, and there is also a separate waterproofing licence. For jobs over $5,000 including GST, the contractor must hold the right licence. Check the licence class on Verify NSW before work starts.
Can you waterproof over existing tiles?
A standard under-tile membrane goes on the prepared wall and floor before tiling, not on top of finished tiles. Surface sealers and regrouting can help worn joints, but they do not replace a failed membrane. If the membrane under the tiles has failed, the usual fix is to strip the area, re-waterproof and re-tile.
How long does bathroom waterproofing take?
What’s The Damage allows about 2 to 3 days for the waterproofing stage of a renovation, including drying time between coats. Drying times depend on the product: some rapid membranes can be tiled in 3 to 4 hours, others need 24 hours. See our guide How Long Does Waterproofing Take to Dry Before Tiling? for data-sheet times.
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