At a Glance
Sydney's inner-city terraces and federation homes often have timber-framed bathroom floors that demand more preparation than concrete slabs. Expect to pay $600–$3,500 per bathroom for bathroom waterproofing in Sydney, with the final figure shaped by floor construction, bathroom size, and whether existing water damage needs remediation before the membrane goes down.
What's Included in the Price
- Surface preparation: grinding, cleaning, and priming the substrate
- Application of a waterproofing membrane system to all wet areas, compliant with AS 3740 Waterproofing of Domestic Wet Areas
- Treatment of all penetrations: drains, tap entries, shower niches, and wall-floor junctions
- Bond breakers and puddle flanges at junctions and drain connections
- Compliance certificate issued on completion
- Inspection coordination: the membrane must be inspected and approved before tiling begins
Materials represent about a quarter of the total cost. The majority is labour, drying time between coats, and the detailing work around penetrations and junctions.
What Affects the Cost
- Floor type. Concrete slabs are the simplest substrate. Timber-framed floors, common in Sydney's older homes, require a compressed fibre cement overlay before waterproofing can begin.
- Bathroom size. A compact ensuite costs far less than a large family bathroom or full wet room.
- Renovation vs new build. Renovation work includes demolition, waste removal, and substrate repair, adding 30 to 50 percent over equivalent new-build waterproofing.
- Shower design. Hobless walk-in showers need more precise falls and broader membrane coverage than step-up designs.
- Strata requirements. Apartments and townhouses in Sydney often require strata approval for any wet area work. Some bodies corporate mandate specific waterproofing systems or independent certification, which adds time and cost.
- Existing water damage. If the old waterproofing has failed and moisture has damaged the subfloor, remediation must happen before the new membrane goes on.
A straightforward standard bathroom in a post-2000 brick veneer home on a concrete slab, with a shower hob and good access, sits toward $600. A full bathroom renovation in a pre-war terrace in Newtown or Marrickville with a timber subfloor, existing rot, a hobless shower, and strata certification requirements pushes toward $3,500.
Sydney-Specific Considerations
Sydney's renovation market drives heavy demand for bathroom waterproofing, particularly in the inner west and inner south. Suburbs like Marrickville, Leichhardt, Balmain, and Surry Hills are dominated by pre-war terraces with timber-framed floors under bathrooms. These floors flex more than concrete, so the membrane system must accommodate movement. Compressed fibre cement sheeting is laid over the timber before waterproofing begins, adding both cost and time.
In apartments and strata properties, wet area waterproofing often requires body corporate approval. Some strata schemes in buildings with known waterproofing defect histories mandate independent certification from an approved inspector, separate from the waterproofer's own compliance certificate. Check your strata by-laws before engaging a waterproofer.
Tiling follows waterproofing as the next step. If you are coordinating trades yourself, the sequence is plumber (rough-in), waterproofer (membrane and inspection), then tiler. Many Sydney waterproofers work closely with tilers and can recommend one, or offer both services.
Hiring a Licensed Waterproofer in NSW
In NSW, waterproofing is a licensed trade. Your waterproofer must hold a current licence issued by NSW Fair Trading. The waterproofing licence class covers any protective treatment to prevent water or moisture ingress, and a contractor licence is required for work valued over $5,000 including GST.
Ask for:
- Current NSW waterproofing licence number
- Compliance certificate on completion
- Confirmation that the membrane will be inspected before tiling
- Public liability insurance
Red flags: A waterproofer who says inspection before tiling "isn't necessary," cannot provide a licence number, or suggests the tiler can just tile over the membrane without anyone checking it. Once tiles go on, the membrane cannot be seen or verified. The inspection before tiling is your only opportunity to confirm the work is correct.
You can verify a licence on the NSW Fair Trading licence check website.
How We Calculate
Estimates are based on surveyed rates from licensed waterproofers in the Sydney metropolitan area, adjusted for property age and typical construction types. All prices include GST. Figures cover standard residential bathroom waterproofing. External waterproofing, swimming pools, and commercial work fall outside these ranges.