Professional Wet Area Waterproofing in Hobart
That black mould creeping up your Hobart bathroom walls? It’s not your housekeeping—it’s failed waterproofing letting moisture penetrate behind your tiles. In Tasmania’s humid climate, proper wet area waterproofing isn’t optional—it’s essential for protecting your home from costly water damage and health hazards.
Last month, I pulled tiles off a 1970s West Hobart bathroom. The owners couldn’t understand why the mould kept returning. Behind those tiles? No waterproofing membrane, just water-damaged timber and mould growing through the wall cavity. What should have been a simple re-tile became a complete structural repair.
We’re licensed waterproofing specialists serving Hobart homeowners throughout West Hobart, Sandy Bay, Glenorchy, Lenah Valley, Kingston, and Lindisfarne. From surface preparation through AS3740 compliance certification, we deliver waterproofing systems that prevent leaks, stop mould growth, and protect your investment for decades.
What Is Wet Area Waterproofing?
Wet area waterproofing is the professional application of waterproof membranes and sealants to moisture-exposed areas in your Hobart home—primarily bathrooms, showers, and laundries—to prevent water penetration into structural elements. This process creates a watertight barrier that protects timber subfloors, wall frames, and building materials from water damage, mould growth, and structural decay.
Here’s what compliant wet area waterproofing includes:
- Liquid or sheet membrane application to floors and walls
- Sealing shower floors with proper drainage gradients
- Waterproofing walls to a minimum height of (150mm above the shower rose, 1800mm in shower areas)
- Creating watertight junctions at corners, penetrations, and drains
- Applying multiple coats for adequate membrane thickness
- Meeting Australian Standard AS3740 requirements
- Providing certification upon completion
In Tasmania’s humid climate, proper waterproofing isn’t just about compliance—it’s about preventing the costly moisture damage I see every week in Hobart homes.
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The Importance of Wet Area Waterproofing in Tasmania's Climate
How Tasmania’s Humidity Affects Bathroom Moisture
Tasmania’s coastal humidity creates constant condensation in Hobart bathrooms. Warm shower steam hits cold surfaces, moisture seeps through grout lines, and without proper waterproofing, it penetrates straight into wall cavities. I’ve opened walls in Lenah Valley homes where timber framing is soft with rot because moisture had an easy path through failed waterproofing.
The Cost of Failed Waterproofing in Hobart Homes
Failed waterproofing costs Hobart homeowners $15,000-$35,000 in repairs—bathroom re-waterproofing ($8,000-$15,000), subfloor replacement ($3,000-$8,000), wall frame repairs ($2,000-$6,000), and mould remediation ($1,500-$4,000). Last year, a Kingston family ignored small mould spots. Six months later, they needed a complete bathroom and subfloor reconstruction.
Protecting Heritage and Older Homes from Water Damage
Heritage Hobart homes weren’t built with waterproofing. Those 1920s cottages in Battery Point have minimal moisture barriers, uneven floors, and timber that’s already been stressed for decades. Modern waterproofing protects these homes while maintaining their character—preventing the structural damage that destroys heritage properties.
Our Certified Waterproofing Process & Methods
Surface Preparation and Substrate Assessment
We start by assessing your substrate condition. Loose tiles get removed, old adhesive gets stripped back, and we check for structural damage. The surface needs to be clean, stable, and properly primed—the membrane won’t bond to dusty concrete or damaged sheeting.
Membrane Application Techniques (Liquid vs Sheet Systems)
We use liquid membranes for most Hobart bathrooms—they’re flexible and handle complex corners and penetrations. Sheet membranes work for simple new construction. Both systems get multiple coats for proper thickness. We reinforce corners, junctions, and penetrations with additional membrane layers.
AS3740 Compliance Requirements and Coverage Areas
AS3740 sets minimum waterproofing heights—150mm above shower roses, 1800mm in shower zones, full floor coverage extending 100mm up walls. We waterproof beyond minimums because Tasmania’s humidity demands it. Every penetration gets sealed, every corner gets reinforced.
Quality Control, Curing Times, and Certification
Membranes need 24-48 hours curing between coats. After final application, we conduct flood testing and provide AS3740 compliance certification—required for building approval and protecting your investment long-term.
Complete Wet Area Waterproofing Solutions
Shower Enclosure Waterproofing (Floors and Walls): Shower waterproofing is where most failures happen. We waterproof the entire shower floor with proper fall to waste, seal the drain connection, and extend the membrane 1800mm up all shower walls. Every penetration—mixer taps, shower roses, towel rails—gets sealed properly.
Bathroom Floor and Wet Zone Protection: Your entire bathroom floor gets waterproofed, not just the shower area. We pay special attention to toilet flanges, vanity plumbing penetrations, and doorway transitions where water migration often occurs in Hobart homes.
Laundry and Additional Wet Area Waterproofing: Laundries need waterproofing too—washing machine overflows, burst hoses, and plumbing failures happen. Other wet areas like toilet compartments, powder rooms with showers, and outdoor shower areas all get proper membrane protection meeting AS3740 requirements.
Why Choose Licensed Waterproofing Professionals
The Risks of DIY or Unlicensed Waterproofing
DIY waterproofing looks easy on YouTube—it's not. I've fixed dozens of failed DIY jobs where homeowners used incorrect products, skipped primer coats, or didn't reinforce corners properly. The waterproofing fails within months, tiles crack, and suddenly that $3,000 professional job becomes a $15,000 repair, including subfloor replacement and mould remediation.
Coordination with Plumbers, Tilers, and Renovation Teams
Waterproofing sits between plumbing rough-in and tile installation. We coordinate timing with your plumber and tiler, ensuring substrates are ready, penetrations are positioned correctly, and membrane curing completes before tiling starts. This coordination prevents delays and ensures each trade can do its work properly without compromising waterproofing integrity.
Waterproofing Requirements for Hobart Bathrooms
Australian Standard AS3740 Minimum Requirements
AS3740 defines where waterproofing must be applied in wet areas. Shower floors need complete coverage with membrane extending up walls—1800mm high in shower zones, 150mm above the shower rose height. Bathroom floors require full waterproofing with 100mm turned up all walls.
Critical Waterproofing Areas (Corners, Penetrations, Junctions)
Corners are where most leaks start. Internal corners get reinforcing tape and extra membrane coats. Pipe penetrations—taps, shower roses, waste outlets—need proper sealing with membrane collars. Floor-to-wall junctions get continuous membrane coverage. Doorway transitions need careful detailing to prevent water tracking under walls into adjacent rooms.
Building Certification and Compliance Documentation
We provide AS3740 compliance certificates after completing work. This documentation proves your bathroom meets building standards—required for council approval, insurance claims, and property sales.
Get Your Hobart Bathroom Properly Waterproofed
Don’t wait until mould appears or tiles start lifting. Proper waterproofing protects your Hobart home from costly water damage and gives you a bathroom that lasts decades without issues.
We provide free waterproofing assessments throughout West Hobart, Sandy Bay, Glenorchy, Lenah Valley, Kingston, and Lindisfarne.
Our licensed waterproofing specialists will evaluate your bathroom, explain exactly what’s needed for AS3740 compliance, and provide a detailed quote with no obligations.
Call 0361526136 now or complete the form below for your free assessment.
Frequently Asked Questions About Wet Area Waterproofing
We typically charge $1,800-$3,500 for standard shower waterproofing, and $3,500-$6,000 for complete bathroom floor and wall waterproofing. The cost depends on your bathroom size, substrate condition, and how many penetrations we’re sealing. Heritage homes with uneven floors or damaged substrates cost more because we’re doing extra prep work. We provide detailed quotes after assessing your specific situation—no surprises once we start.
Most shower waterproofing takes 2-3 days—one day for surface prep, then multiple membrane coats with a 24-48-hour curing time between applications. Complete bathroom waterproofing takes 3-5 days. We won’t rush curing times just to speed things up. The membrane needs proper drying, or it won’t bond correctly, and you’ll have problems down the track.
No, and anyone telling you they can is setting you up for failure. We need to remove tiles and get back to a clean substrate for the membrane to bond properly. Waterproofing over tiles means the membrane is only stuck to the tile surface—when tiles eventually fail, your waterproofing fails with them. We do it right, or we don’t do it.
Yes, absolutely. Building codes require new waterproofing whenever you’re doing bathroom renovations. Even if old waterproofing looks okay, it’s been compromised when tiles were removed. We’re also not certifying someone else’s decade-old work. Fresh waterproofing means you get AS3740 certification and warranty protection.
Waterproofing creates a complete moisture barrier under your tiles using specialised membranes. Sealing is just applying grout sealer or silicone to finished surfaces—it helps, but doesn’t stop water from penetrating through grout into substrates. You need a proper waterproofing membrane under tiles, then sealing on top as extra protection. They’re not interchangeable.
