What Affects the Cost
Surface problem vs membrane failure. Cracked grout or peeling silicone is a surface fix costing a few hundred dollars. Water staining on the ceiling below means the membrane has failed. Very different scope, very different cost.
Duration of the leak. Weeks of leaking causes surface damage. Months or years of leaking rots timber framing and creates structural problems that must be repaired before new waterproofing goes on.
Shower type. Hobless walk-in showers have more membrane area and more complex drainage junctions than step-up (hob) designs. Under AS 3740:2021, the minimum fall to waste is 1:80.
Timber subfloor condition. Many Sydney terraces and older homes have timber-framed bathroom floors. If the timber has rotted from prolonged leaking, it needs replacement before new waterproofing. Timber remediation adds $1,000–$3,000+ to the total.
Grout type. Epoxy regrout ($800–$1,500) costs more than cement-based ($600–$1,200) but lasts roughly twice as long and does not require periodic sealing.
Previous repairs. If regrouting or injection sealing has already been tried and the leak returned, the membrane has failed. The money spent on those repairs is gone.
Strata and insurance. In apartments, a leaking shower that damages the unit below involves the body corporate. Under NSW strata law, waterproofing within your lot boundary is the lot owner's responsibility. Strata insurance may cover some of the water damage, but the waterproofing repair itself typically falls to the unit owner. Start with your strata manager.
A silicone and grout reseal on a standard shower hob with intact membrane in a post-2000 home sits toward $250. A full strip-out in an older terrace with timber subfloor, rotted framing, membrane replacement, and full retiling pushes toward $4,200.
Sydney-Specific Considerations
Shower leaks are one of the most common waterproofing issues in Sydney. The city's mix of ageing apartment stock and older inner-city terraces creates two distinct repair profiles.
Inner-city terraces (Balmain, Newtown, Surry Hills, Marrickville). Timber-framed bathroom floors are standard in these homes. When the waterproofing membrane fails, water penetrates the timber, which swells and rots over time. By the time a homeowner notices a stain on the ceiling below, the timber framing may already be soft and spongy. Repair in Balmain and Newtown terraces frequently involves cutting out and replacing sections of timber framing before the new membrane can be applied. A flood test before committing to the strip-out confirms whether the membrane is the source, not just the grout.
Ageing apartment stock (Zetland, Mascot, Rhodes, Parramatta). Sydney's 1990s and 2000s apartment buildings are now 20 to 30+ years old, and original waterproofing membranes are reaching end of life. A shower leak in a strata building that reaches the unit below creates a dispute about responsibility. Under the NSW Strata Schemes Management Act, waterproofing within your lot boundary is your problem. If it damages common property or another lot, the body corporate and strata insurance get involved. Many strata managers now require a waterproofing compliance certificate before sign-off. Compact apartment showers (3–5m2) are quicker to strip and retile, which keeps costs toward the lower-to-mid range even for membrane replacement.
Injection sealing. Popular in Sydney as a first attempt because it avoids tile removal. Companies like Megasealed can complete the treatment in a few hours. It works for minor grout and silicone failures, but if the membrane itself has failed, the effect is temporary. If you have had injection sealing done and the leak has returned within a year or two, the next step is a full strip-out.
Water tracks sideways. The stain on your ceiling or wall may not be directly below the leak source. Water follows framing members, gravity, and the path of least resistance. The visible damage can appear some distance from the actual point of membrane failure. In terraces along the inner west, it is common for a shower leak on the first floor to show up as dampness in a ground-floor wall metres away from the bathroom above.
Hiring a Licensed Waterproofer in NSW
Shower leak repair involving membrane work must be performed by a licensed waterproofer. In NSW, verify licences through NSW Fair Trading. A contractor licence is required for any work over $5,000 including GST.
A good waterproofer will offer a flood test before recommending a full strip-out, provide a written quote that separates diagnostic, waterproofing, and tiling costs, and issue a compliance certificate on completion.
Worth checking:
Flood test or leak detection offered before committing to a full strip-out
Compliance certificate issued on completion
Pre-tiling inspection confirmed if membrane is replaced
Written scope clarifying whether retiling is included or quoted separately
How We Calculate
Estimates are based on surveyed rates from licensed waterproofers in the Sydney metropolitan area, adjusted for typical property construction in NSW. All prices include GST. Figures cover standard residential shower leak repairs. Full bathroom waterproofing, cosmetic repairs to adjacent rooms, and commercial work fall outside these ranges.