Dark or swollen skirting
Skirting boards, door jambs or architraves beside the bathroom that swell, blister or darken at the base are almost always drawing moisture from a failed floor to wall junction inside the wet area.
Bathroom waterproofing
Bathroom waterproofing that passes inspection the first time
HydroForce installs certified wet area membrane systems in bathrooms across Brisbane, the Gold Coast and the wider South East Queensland corridor. Every job is set out to AS 3740, flood tested for a full 24 hours and handed over with a signed compliance certificate.
Overview
What bathroom waterproofing actually involves
A bathroom is the hardest working room in an Australian home. It takes steam, splash, thermal movement and constant foot traffic, and it does all of that sitting directly above a timber or concrete floor structure with no tolerance for sustained moisture. Waterproofing is the layer that keeps those two realities apart. It is not the tiles, not the grout and not the silicone. It is a continuous, flexible membrane installed beneath everything you can see, engineered so that any water passing through the tile bed is caught, contained and directed back to the floor waste.
Under AS 3740, a bathroom is treated as a series of zones with different requirements. The shower enclosure carries the heaviest obligations: walls inside the shower must be protected to a minimum height, the enclosure floor must be fully waterproofed, and where the shower sits on a timber floor or upstairs, the whole bathroom floor becomes a waterproofed surface. Outside the shower, the perimeter junction between floor and wall still has to be sealed with a rise up the wall, plus protection around the bath, basin and any fixture where water is likely to land.
Where bathrooms fail is rarely in the field of the floor. It is in the details. The junction where the slab meets the wall sheet moves seasonally. The pipe penetration for the shower waste is a hole cut through the substrate. The hob at the shower entry is a separate element bonded to the floor. Each is a discontinuity that needs a bond breaker, a reinforcing bandage or a purpose made collar before the membrane goes over the top. Skip that and the membrane tears along the junction the first time the building moves, usually within eighteen months of handover.
HydroForce treats the bathroom as a complete system rather than a coat of product. We assess the substrate, correct the falls if drainage is wrong, prime to manufacturer specification, install every reinforcement detail, then build the membrane in two measured coats. The result is a bathroom that will still be dry in a decade, and paperwork that satisfies a private certifier without a second visit.
Scope of works
What is included in a HydroForce bathroom job
Every quote covers the full system, not just the membrane coats. Nothing on this list is an optional extra.
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Substrate assessment and correction
We check the floor for falls to waste, drummy sheeting, movement joints and moisture content before anything is applied. Where falls are wrong or the screed has failed, we quote the correction rather than membrane over a problem you will pay for later.
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Mechanical preparation and priming
Surfaces are ground, vacuumed and primed with the system primer matched to the substrate, whether that is a concrete slab, compressed fibre cement sheet or a wet area rated wall lining.
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Bond breakers at movement joints
Floor to wall junctions, internal corners and hob junctions receive a bond breaker so the membrane can stretch across the joint instead of tearing when the building moves.
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Reinforcing bandage and collars
Every internal corner, junction and change of plane is bandaged. Every penetration, including waste outlets, tap sets, shower rails and mixer bodies, is collared and sealed.
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Two measured membrane coats
The membrane goes on in two coats at full specified wet film thickness, with the second coat rolled at ninety degrees to the first so coverage is even and pinhole free.
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Flood test and certification
The completed wet area is flood tested for 24 hours. Once it holds, you receive stage photographs, an AS 3740 compliance certificate and your signed 7 year workmanship warranty.
What to look for
Signs your bathroom waterproofing has failed
Failures rarely announce themselves. By the time damage is visible, water has usually been tracking through the structure for months.
Staining on the ceiling below
A brown ring or a soft patch underneath a second storey bathroom means water has passed the membrane and is sitting in the floor structure. This is the most urgent failure mode.
Loose, drummy or lifting tiles
Tiles that sound hollow when tapped, or grout that keeps cracking in the same line, usually mean the tile bed is holding water and the bond is breaking down from underneath.
Efflorescence at the shower base
White powdery deposits at the base of the shower or along the hob are salts carried out of the screed by water moving through it.
A smell that will not clear
A persistent musty odour in a well ventilated bathroom is a strong indicator of trapped moisture in the wall cavity or floor structure.
Paint bubbling on the far side
Blistering paint on the outside face of a bathroom wall, particularly in a hallway or bedroom, means moisture is passing through the wall sheet from the wet side.
Standards
Compliance, certification and warranty
In Queensland, waterproofing is licensed work. The QBCC requires a licence to carry out waterproofing on residential wet areas, and the work must comply with AS 3740 as referenced by the National Construction Code. HydroForce holds the appropriate licence class, carries public liability cover, and every applicator on our crews works to the same documented method regardless of which job they are on.
That matters more than it sounds. If waterproofing is installed by an unlicensed operator, the work may not be covered by the Queensland Home Warranty Scheme, and a future buyer's building inspector will flag the absence of a certificate. When you sell, that missing paperwork becomes a negotiating point against you. When you claim, it becomes a reason for the claim to be refused.
Included with every job
- AS 3740 compliance certificate issued for every completed wet area
- Photographic record of preparation, detailing, membrane coats and flood test
- Product batch and system data sheet supplied with the certificate
- Signed 7 year workmanship warranty, transferable to a new owner
- QBCC licensed applicators and full public liability cover
- Documentation emailed on the day of completion, not weeks later
Explore more
One of four wet area services we deliver
Shower Waterproofing
Certified wet area systems, flood tested and documented across South East Queensland.
View service →Laundry Waterproofing
Certified wet area systems, flood tested and documented across South East Queensland.
View service →Commercial Waterproofing
Certified wet area systems, flood tested and documented across South East Queensland.
View service →Where we deliver bathroom waterproofing
- Brisbane
- Gold Coast
- Sunshine Coast
- Ipswich
- Logan
- Redlands
- Moreton Bay
- Toowoomba
FAQ
Bathroom waterproofing questions we are asked most
How long does bathroom waterproofing take from start to finish?
A standard bathroom takes about three days end to end. Day one is preparation, priming and detailing, day two is the second membrane coat once the first has cured, then the area is flood tested for 24 hours before we release it. Larger bathrooms or jobs needing substrate repair can run longer, and we give you the realistic timeline at quote stage so your tiler can be booked with confidence.
Do I need to waterproof the whole bathroom floor or just the shower?
It depends on the construction. Where the bathroom sits on a timber floor, on an upper storey, or above habitable space, the entire floor is treated as a waterproofed surface. On a ground floor slab with a fully enclosed shower, the standard allows a smaller footprint, though the shower floor, the shower walls to the required height and the full floor to wall perimeter junction are always included. We confirm which case applies at the inspection.
Can you waterproof over existing tiles?
In limited situations, yes. There are membrane systems designed for sound, well bonded tiles with the correct primer, and they can work well in a laundry or low risk area. For a shower or a bathroom with a suspected failure we do not recommend it, because sealing over trapped water simply moves the problem. We inspect first and give you a straight answer either way.
What happens if the flood test does not hold?
We find the fault and fix it before anything else happens on that job. That is exactly why the test exists, and it is far cheaper to correct at membrane stage than after the tiler has finished. A failed test costs you nothing extra because rectification at that point is our responsibility under the fixed quote.
Do you work directly with homeowners or only with builders?
Both. Around half our residential work comes from builders and renovation contractors running a program of jobs, and the rest comes straight from homeowners managing their own renovation. If you are owner building, we explain exactly what the certifier will look for so nothing holds up your inspection.
When can my tiler start after the membrane is done?
Once the flood test has passed and the water is drained, the area is ready. In practice your tiler can be on site the morning after the test is drained, and we are happy to coordinate directly with them.
Next step
Book your free bathroom waterproofing quote
Call HydroForce and speak to a licensed applicator today, or request a time slot online and we will confirm your site inspection the same business day.