How much does it cost to waterproof a bathroom?

Bathrooms are one of the most frequently used domestic wet areas in any home. Bathroom waterproofing is necessary to ensure the structure of your property remains uncompromised.

If you’re wondering how much to waterproof a bathroom, the average cost is between $500 and $1000, but in some cases it can be up to $4,000, depending on the size of the bathroom, scope of the project and materials used.

Without proper bathroom waterproofing, your property will be exposed to damp, water leaks and condensation, which can cause structural issues and significant damage to your home. Inadequate bathroom waterproofing can also create mould issues and expose tiling to water damage causing swelling and cracking.

In this guide, we will explore what bathroom waterproofing is, the steps involved in waterproofing your shower or wet area, bathroom waterproofing costs and Australian standards, and how to hire a tiler and waterproofer for your home project.

Want to find the right bathroom renovation company in Sydney, Melbourne, Brisbane, Adelaide or Perth?

What is bathroom waterproofing?

The process of waterproofing a bathroom is an important part of any complete bathroom renovation. Quality waterproofing materials will stop moisture from causing damage, provided it’s installed correctly.

In wet areas where you require plumbing fixtures in your home, you will likely need waterproofing around the walls and floors. Quality waterproofing membranes are installed to prevent leaks and structural damage from occurring.

Waterproofing materials include:

• Waterproofing membrane
• Waterproofing agent
• Primer
• Bathroom sealing silicone

Faulty waterproofing is one of the top building defects in Australia and can cause as much trouble to your home as termites. Faulty waterproofing is a result of inferior waterproofing membranes, inadequate preparation and poor application. When it comes to sealing bathrooms, we recommend using professional waterproofing specialists.

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Step-by-step shower waterproofing process

Shower waterproofing for both the walls and floors should be carried out using the highest quality materials for the job to ensure it stands the test of time.

Shower waterproofing is best done by a professional. If you have trades experience and follow the Australian standards, you might be able to do the job yourself. It’s best to check with your local authority.

When waterproofing a shower, you will need:

• Paint roller and tray
• Paint scraper
• Masking tape
• Safety equipment, such as goggles to protect your eyes
• Spirit level primer
• Waterproofing agent and membrane
• Caulking gun
• Hammer and knife
• Cleaning equipment

Basic steps for waterproofing a wet area:

Step 1: Clean the shower walls and floor area you need to waterproof, ensuring your remove any dust or grit, particularly if you have removed tiles to complete bathroom renovations.

Step 2: Add the primer by rolling it on the walls and floor, covering any area where tiles will be installed.

Step 3: Once the primer has dried, seal the gaps with silicone sealant removing any excess with the paint scraper, and let it dry properly overnight.

Step 4: Use masking tape on the wall to level out where you want to waterproof. Following the lines of the primer is a good gauge for this. If you’re waterproofing a shower area, you need to add the tape and the primer to a height of at least 1.8 metres.

Step 5: Now it’s time to start waterproofing! Roll on the waterproofing agent to the height of the tape and all over the floor of the shower. The agent will be a little sticky as it dries so make sure you are very careful with this step. Add the waterproofing membrane to the joints and make sure that everything is covered and there are no gaps before painting over it with the waterproofing agent.

Step 6: Add a second coat of the waterproofing agent 24 hours after the first application to make it super strong. Once everything is dry, you’re ready to start adding tiling to the shower area.

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Waterproofing bathroom walls before tiling

It’s important to note that when conducting a bathroom renovation, bathroom walls and floors are waterproofed before adding tiles. If your shower is not waterproofed properly, swelling and cracking tiles will be a sign of a job poorly done, and it will cost a lot more in the long run to fix these types of problems.

Want to find the right bathroom renovation company in Sydney, Melbourne, Brisbane, Adelaide or Perth?

Australian standards for bathroom waterproofing

Bathroom waterproofing must meet national standards and comply with the Building Code Australia (BCA).

To be compliant with the Australian standards:

• The full shower floor must be waterproofed
• The step down from the shower to the bathroom floor must be waterproofed to at least 100mm
• If the floor is made of timber or the bathroom is situated on the second storey or higher, the floor must be entirely waterproofed
• The shower walls must be waterproofed by at least 1800mm
• The bathroom walls must be waterproofed by at least 150 mm.

In Queensland and New South Wales, waterproofing must be carried out by a licensed waterproofer. In all other states, the work can be conducted without a license as long as it meets the Australian standards.

How much does waterproofing cost?

Waterproofing a bathroom costs about $40 per square metre on average. If you have a medium-sized bathroom, you can expect to pay anywhere between $800 and $1000 for professional waterproofing. This cost includes the labour, materials and waterproofing agent.

The overall price of waterproofing will depend on a range of factors, such as the size of the bathroom and the layout. More complex or larger jobs can cost as much as $4,000.

Waterproofing shower cost

The cost of waterproofing a shower will come down to the size of the shower and the hours involved. It’s often a cheaper procedure than a full bathroom waterproofing. If you are considering waterproofing a shower area, you can expect to pay anywhere from $600 to $3,000.

The best way to get accurate waterproofing prices is to ask your local specialist for a quote. Professional bathroom waterproofers will provide a complete service and can work with your local tiler to provide a quality service. Many tilers are also qualified to waterproof bathrooms, and you can ask them about the cost to waterproof bathroom showers when requesting a quote.

Once the waterproofing has been carried out, the tiles can be laid, towel rails installed, and your bathroom renovation will be near completion.

What determines total waterproofing price?

There are several factors that will influence how much waterproofing costs for your bathroom. These include:

• The size of your bathroom: A bigger bathroom means more materials and a longer time to complete the job, which adds to labour costs.
• Materials: The quality of the waterproofing membrane used will influence the waterproofing price, and you don’t want to scrimp here with low-quality products.
• Your location: Labour rates differ across the states and regions.
• The location of your bathroom: Total floor waterproofing is necessary for second storey (or higher) bathrooms.
• Emergency service: If you need an urgent service, this usually comes with steeper hourly rates.
• Any repairs required: Existing damage to shower walls and floors will need fixing before any waterproofing work can be done.

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Hiring bathroom waterproofers

Bathroom waterproofers can cost anywhere from $50 to $150 per hour. Bathroom renovation specialists charge about $65 per hour, tilers charge between $50 and $150, and waterproofing specialists are roughly $35 per hour.

Ensure whoever you hire has the necessary waterproofing license and has provable experience in the industry, whether that’s a tiler, builder, bathroom renovator or waterproofing expert.

How to get waterproofing quotes

When looking for waterproofing quotes, ensure you get at least three to compare. To get an accurate indication of waterproofing prices, you’ll need to know which areas will be worked on, the type of material that will be used and how long the job will take to complete.

If you’re in New South Wales or Queensland, ensure you ask to see a copy of the tradesman’s waterproofing license and qualification. It’s a good idea to hire someone with a qualification in waterproofing no matter which state you live in.

Also, request a list of references and verify whether there will be a warranty on works completed. Yellow Pages can provide you with free quotes from local waterproofing experts in your area.

Bathroom waterproofing cost FAQ

How much is waterproofing bathroom cost per m2?

Waterproofing a bathroom costs between $35 and $60 per square metre, with the average rate being $40 per square metre.

How much to waterproof a small bathroom?

For waterproofing a small bathroom, the average price you can expect to pay is $500.

How long does waterproofing last?

How long waterproofing lasts depends on the quality of materials used. A high-quality waterproofing sheet membrane that has been applied professionally should last a minimum of ten years and much longer. Most products will come with a ten-year warranty for peace of mind.