How to Waterproof a Bathroom

Information you need to know before waterproofing a Bathroom.

Expert Guide On How To Waterproof a Bathroom


waterproofing bathrooms

Waterproofing Your Bathroom

Faulty waterproofing is one common challenge homeowners face with their property. The Australian Master Tilers Association (AMTA) backed this up with a report that faulty waterproofing is one of the top three challenges in homes. What makes faulty waterproofing more challenging is how it can easily result in structural damage.
But what is waterproofing, and who should handle it when it is faulty? These and other questions are what this piece looks into.

What Is Waterproofing?

While a water-resistant material prevents the movement of water, waterproofing material doesn’t only prevent water movement but is also efficient at preventing moisture. The latter is used in wet parts of the home to ensure that moisture doesn’t escape into dry parts of the home, preventing water damage.
A typical residential home contains different wet areas known to contain sanitary fixtures and appliances, subjecting the areas to high moisture levels. Moisture in a residential home is often a result of condensation, high humidity levels, and wetting.
Waterproofing is required in moisture-prone parts of the home, including showers, bathrooms, laundry, and kitchen.

Australian Standards for Waterproofing in Bathrooms and Wet areas

Each Australian state has different waterproofing regulations. However, the states share a few general rules, majorly found under the Building Code of Australia (BCA). 

The general rules include.

•  Waterproofing is compulsory in the shower. While waterproofing should cover the whole shower floor, it should be applied to the wall to a height of 1,800 mm.

•  Waterproofing should be applied to the bathroom walls to a height of 150 mm

•  The steps from the floor to the shower must be waterproofed to at least a height of 100 mm. 

•  Homeowners should waterproof the whole bathroom floor, with the exception of the one on the ground floor. 

•  Regardless of which floor the bathroom is located, waterproof the whole floor if the bathroom contains any wood.

Main Different Types of Waterproofing Available in Australia

Different waterproofing products are applied in the home, and the best one depends on the part to waterproof. 

While some products are rubber sheets, which are rolled out, and others are in liquid form, which is applied to the surface with a roller or brush. For example, the liquid type is commonly used in bathrooms, owing to the advantage of high flexibility. Plus, the type is easy to install.

According to the CSIRO, liquid membranes have different abilities to stretch, resulting in three different classes. 

Class 1:  This includes water-based epoxies and metal, which adds a 65% extension to its original length. 

Class 2:  Bitumen-based membranes and acrylic membranes are found under this class and can expand between 65% and 200%. 

Class 3:  This includes PVC sheet membranes and solvent-based polyurethane. Products in this class can expand more than 200% plus their original length.

Why You Should Use Waterproofing?

Many reasons warrant waterproofing wet areas in a home. Waterproofing moisture-prone areas in a home helps prevent water from seeping out from the areas to other parts of the home. Again, water damage is a common challenge in homes, and as a homeowner, you want to do everything to prevent it. 

Here are the possible results of water penetrating to dry parts of the home.

Mould and mildew : This causes spores in the air, which is unhealthy, especially to asthmatic patience and occupants with any other respiratory problem.

Structural damage : Uninvited moisture can go to the extent of damaging the structure, especially when left unattended for long. For example, when water eats deeply into a structure’s joists and beams, the structure loses strength. 

Corrosion of plumbing : Water escaping to areas with pipes can damage the home’s piping, resulting in leaking pipes – a more detrimental home problem.

Electrocution :  Water is a good conductor of electricity. If left to find its way to the electric fittings in the home, it can cause the risk of electrocution in the home.

Concrete cancer : When the steel in the home’s concrete is subjected to water, the steel expands and causes the concrete to expand too. When this happens, the concrete cracks, weakening the foundations. 

These points show that waterproofing is essential in every residential home.

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Benefits of Waterproofing

Waterproofing wet areas in a residential or business building helps: 

Prevent leaks: this ensures that water doesn’t penetrate through cracks in the walls and floors, preventing the risk of structural repairs in the long run.

Provides insulation: waterproofing is effective at preventing heat loss in the home, ensuring owners spend less on heating costs in winter.

Increases property’s value: waterproofing is one improvement for your property to add to its value. Studies show that property with waterproofing attracts buyers with higher prices. 

Who Is Qualified To Waterproof Your Property?

While there are different reasons to waterproof your property, it is equally important to note that the job of waterproofing should only be carried out by selected tradespersons, such as a tiller or a builder. Trusting the job to a professional ensures you have the best of your investment.

Australian states are different with documents to tender to prove the completion of the job according to the law. For example, New South Wales and Victoria require that contractors tender certification for the job, while some other territories (not all) require that the contractor provide a written declaration that the job was carried out in alignment with the Australian Standard AS3740-2010, which sees into waterproofing domestic wet areas.


Different waterproofing membranes require different substrates and adhesives, and the one to choose depends greatly on which ones are compatible with each other. This goes with adding that curing time should be accurate, and the products used should comply with the Plumbing Code of Australia and other acts regulating product quality.
While you might want to install waterproofing yourself, it is best to consider the impact of an unprofessional job on your property. Also, though it might seem wise to cut back on costs by hiring an unlicensed contractor, think of the challenges you will face with your property’s insurance, should you need to make a claim in the long run.

The Cost Of Getting A Bathroom Waterproofed?

The expenses can differ while getting a bathroom waterproofed. A large part of the expense is dictated by the size of the bathroom or wet area.

The ideal approach to determining the cost is getting your free quote from a qualified water proofer like Tiler Tiling Perth.
Waterproofing expenses can differ between the types of membranes to be used. But as an estimate, waterproofing can cost anywhere from $50.00 per m2.
For a normal estimated bathroom, you could expect to pay between $350 – $1000.

Leading causes of waterproofing failure

When waterproofing fails, this can cause big problem's if it's not corrected asap. There are many different causes why waterproofing can fail. Still, the number one for failed waterproofing is using an unskilled trade as they may not have been correctly trained to Australian Standards. Usually, you would see failed  waterproofing has been misapplied, or the wrong membrane has been used.

Here are some main facts about failed waterproofing :

Incorrect waterproofing work

When hiring a trade to do your waterproofing, make sure they have years of experience with a good track record, so you don't have costly issues later in the future. Bad workmanship from an unskilled applier can lead to leaking issues in your shower or balcony. A skilled applier will make sure they use only the best quality, correct waterproofing and primer for your situation.

Leaking problems from higher levels

In high-rise buildings or double story homes, you will generally see many leaking issues from failed waterproofing in showers and balconies. Leaking plumbing and damaged roof areas also can cause this problem.


In any wet area situation, in your home or office you must always maintain and check the areas for any signs of leaks; this could be cracked grout or silicone in the shower or lose drummy tiles on your balcony.

An incorrect waterproofing membrane has been applied

You must always make sure the waterproofing and primer been used is the correct type for your situation. There are many different types on the market today. That's why you should only use a trained professional or get expert advice from your local tilers and waterproofers Tiler Tiling Perth.

Waterproofing How Long Does It Last?

How long a waterproofing sheet membrane lasts depends on two factors: the quality of the membrane and the installer’s professionalism. A quality waterproofing membrane will last for a long time if trusted in the hands of a professional tiller for installation.
Waterproofing membranes come with different warranties, depending on the brand. However, most membranes come with a minimum of a 7-year warranty.




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