What Affects the Cost
Surface vs membrane failure. A grout and silicone reseal is a few hundred dollars. A failed membrane requires tile removal and full replacement costing several thousand. A flood test ($100–$200) confirms which you are dealing with.
Injection sealing history. Injection sealing is popular in Perth as a first-attempt fix. It can buy time, but if it has already been tried and the leak returns, the membrane needs replacing. The cost of the injection sealing is gone.
Grout type. Epoxy regrout ($800–$1,500) is particularly well suited to Perth's hard water. Cement-based grout ($600–$1,200) absorbs mineral deposits and discolours faster.
Shower type. Hobless walk-in showers have more membrane coverage and more junctions than step-up (hob) designs. Falls to drain must meet the AS 3740:2021 minimum of 1:80.
Water travel distance. On Perth's slabs, water from a failed membrane can travel a considerable distance from the source, making diagnosis more complex and sometimes requiring specialist flood testing.
Tile condition. If tiles are cracked, hollow-sounding, or discontinued, partial repair is not feasible and full retiling is needed.
Trade availability. Perth's smaller pool of specialist waterproofers can affect quotes and extend booking lead times to 2–4 weeks.
A silicone reseal on a standard shower hob with intact membrane in a modern Baldivis or Ellenbrook home sits toward $250. A full strip-out in a 1990s Scarborough or Doubleview home with failed membrane, injection sealing that did not hold, and full retiling pushes toward $4,000.
Perth-Specific Considerations
Perth's housing stock and dry climate create a specific pattern for shower leak diagnosis and repair.
Slab behaviour (Baldivis, Ellenbrook, Joondalup, Canning Vale). Nearly all Perth homes are built on concrete slabs. When a shower membrane fails, water does not drop through the floor. Instead, it spreads along the slab surface, appearing as damp patches or tile lifting in adjacent rooms, hallways, or even bedrooms. The visible damage may be metres from the actual failure point. Flood testing the shower base (blocking the drain and filling with 10–20mm of water for 24 hours) is the most reliable way to confirm the shower as the source. For slab homes, the good news is that there is no timber subfloor to rot, so the repair scope is more predictable once the membrane is confirmed as the issue.
Mining-boom construction (2003–2012). Scarborough, Doubleview, Karrinyup, Stirling. Many homes built during Perth's construction boom are now 15 to 20+ years old. Original waterproofing membranes in these homes are approaching the end of their typical 15-to-20-year lifespan. If your shower was part of the original build from that era and you are seeing any signs of moisture in adjacent rooms, a proactive flood test can confirm the membrane condition before damage spreads.
Injection sealing. Perth has a strong market for injection-based shower sealing. Companies inject products behind tiles to create a secondary barrier without removing tiles. The service typically costs $700–$1,500 and takes a few hours with no disruption. It can work well for minor grout and silicone failures. It is not a permanent fix for a failed membrane. If injection sealing has already been done and the leak has returned, the next step is a full membrane replacement.
Dry climate masking. Perth's dry conditions mean moisture from a shower leak evaporates faster than in humid cities like Brisbane. A leak can persist for months or even years before visible signs appear. Subtle indicators to watch for: unexplained dampness in rooms adjacent to the bathroom, a faint musty smell, slight discolouration near skirting boards, or tiles lifting in hallways near the bathroom.
Hiring a Licensed Waterproofer in WA
Shower leak repairs involving membrane work require a registered building practitioner. In WA, waterproofing falls under general builder registration through Building and Energy (DMIRS). Verify registration on the Building and Energy licence search.
A good waterproofer will offer a flood test before recommending a full strip-out, provide a written quote separating diagnostic, waterproofing, and retiling costs, and issue a compliance certificate on completion.
Worth checking:
Current builder registration covering waterproofing (verify on the Building and Energy search)
Flood test 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 registered waterproofers in the Perth metropolitan area, adjusted for typical construction types in WA. All prices include GST. Figures cover standard residential shower leak repairs. Full bathroom waterproofing and cosmetic repairs to adjacent rooms are excluded.