How to waterproof concrete floor

How to waterproof concrete floor

You are likely visiting this webpage because you want to waterproof a room in your home or compare your contractors’ work. Whatever your reason, I hope the information provided here will help you understand the process better.

There is a wall of text for reasons and logic, but if you want to get into the fine details, hop to the end. You might find some of this text interesting, as it is for me.

Waterproofing is a crucial process that prevents water from seeping into a building’s structure and causing damage. While it’s optional in some locations, the regulations and mandates vary from one place to another.

For instance, in some areas, waterproofing is only necessary in bathrooms and balconies, while in others, it’s also required in decks and elevated walkways.

In Australia, waterproofing is mandatory in every apartment area, including bathrooms, laundries, and kitchens. Every room with a water outlet must undergo waterproofing to prevent water damage.

Looking into the future, it’s predicted that waterproofing will become even more regulated in the coming years. Investing in waterproofing during renovation can be a wise decision, as it will help protect your property from water damage and ensure it remains structurally sound for years to come.

When it comes to making investment decisions, a range of factors must be taken into account. One such factor that may sway your decision is the availability of waterproof options.

Such options can provide an added layer of protection against damage and deterioration, increasing your investment’s longevity and overall value. Therefore, it’s essential to carefully consider the benefits of waterproofing before making your final choice.

Waterproofing concrete floors is essential to prevent water damage and maintain the structure’s integrity. Concrete floors in basements, garages, and outdoor spaces are particularly vulnerable to water damage.

Basements are especially prone to flooding and moisture buildup, which can lead to the growth of mold and mildew. Waterproofing these floors can prevent water from seeping through the concrete and causing damage to the foundation, walls, and other parts of the building.

When it comes to basements, it is essential to keep in mind that they can be susceptible to water capillary rise. This occurs when moisture seeps through the concrete walls and floors due to the natural tendency of water to move upwards through porous materials, leading to problems.

If you are experiencing moisture in your basement due to capillary rise, it is essential to note that more than waterproofing is needed to solve the issue. Capillary rise requires a specific set of solutions to address it adequately.

It is crucial to look closely at the groundwork and drainage systems to ensure they function correctly to prevent further damage. Only then can you take the necessary steps to resolve the moisture issue and enjoy a dry, healthy basement environment.

Similarly, garages and outdoor spaces are exposed to the elements, making them susceptible to water damage. Waterproofing these floors can protect them from rain, snow, and other forms of moisture, which can cause cracking, spalling, and other damage.

Waterproofing and proper drainage can protect from water damage.

What are the benefits of waterproofing?

So, we have already established that waterproofing concrete floors is essential in ensuring any building or structure’s long-term durability and stability.

Concrete floors are highly susceptible to water damage, which can lead to costly repairs and structural issues down the line. Applying a waterproofing coating to concrete floors can prevent water from seeping into the concrete and causing damage.

This can help extend the concrete’s lifespan, increase the building’s structural integrity, and reduce the risk of mold and mildew growth. Waterproofing concrete floors can also improve the overall appearance of the space, as it can prevent unsightly water stains and discoloration.

Overall, the benefits of waterproofing concrete floors are numerous and can help ensure any structure’s safety, longevity, and aesthetic appeal.

Prepare the floor for waterproofing

What I’m about to list here is universal. It applies to all, if it’s a balcony, deck, kitchen, or bathroom.

  • Clean the floor

For a concrete floor, it is essential to have a level surface to ensure that the installation of the flooring material is successful. I recommend using an angle grinder with a construction vacuum cleaner attached to it to achieve this.

This will help to open up all the pores on the surface of the concrete, ensuring that the adhesive has the best possible grip on the concrete.

It is important to note that any noticeable bumps or irregularities on the floor will cause problems when installing the floor tiles or any other type of flooring. Therefore, it is crucial to ensure the floor is level and smooth before installing the flooring material.

  • Patch the cracks and holes on the floor.

To ensure that your waterproof membrane is as effective as possible, it’s important to patch any visible cracks and holes in the floor before installation. This is because any gaps or openings can compromise the integrity of the membrane and allow water to seep through. 

Fortunately, most waterproof membrane manufacturers offer a specialized product that works seamlessly with their membranes. This product is typically formulated to adhere perfectly with the surface membrane product, ensuring a tight and secure seal over any cracks or holes. 

When using this type of product, following the manufacturer’s instructions carefully is essential to ensure the application is done correctly. Using the wrong type of patching material can cause compatibility issues and potentially compromise the effectiveness of the membrane. 

By taking the time to properly patch any cracks and holes in the floor before installing your waterproof membrane, you can ensure that your flooring is protected from water damage and will last for years to come.

  • Sand or grind the floor after patching is done.

Maintaining a level floor is crucial for a successful membrane or flooring installation. If patches are on top of the level floor, it will no longer be level and can cause complications during installation.

Not only will this compromise the structural integrity of the final product, but it will also look unprofessional. Therefore, avoiding any patches on top of the level floor is highly recommended to ensure a smooth and professional-looking installation.

  • Vacuum clean it as dust-free as possible.

Before applying waterproofing to a concrete surface, ensuring it is as clean as possible is crucial. Any dust or debris on the surface can fill the concrete pores, significantly weakening the waterproofing material’s adhesion to the surface.

To avoid this, it is recommended to thoroughly clean the surface with a broom or brush to remove any loose debris or dust particles. For best results, a high-pressure washer may be used to ensure the surface is free from contaminants.

This simple precaution ensures that the waterproofing material adheres properly to the concrete surface and provides long-lasting protection against water damage.

Choosing the suitable waterproofing material

The most common waterproofing material for concrete floors is a concrete waterproofing coating. These coatings can be either cementitious or acrylic-based and are designed to penetrate the pores of the concrete and form a barrier against water penetration.

Cementitious coatings are made from a mixture of cement, sand, and water and are typically applied in two or more coats. On the other hand, acrylic-based coatings are made from a mixture of acrylic resins and water and are usually applied in a single coat.

Both coatings effectively waterproof concrete floors and provide long-lasting protection against water damage. It is essential to choose a high-quality waterproofing coating and to follow the manufacturer’s instructions for application and maintenance to ensure the best results.

When choosing a waterproofing material, there are several factors that you need to consider. These include the type of surface that needs waterproofing, the required level, the weather conditions in your area, and your budget.

It would help if you also thought about the durability and lifespan of the material, as well as its ease of installation and maintenance. Lastly, it would help to compare different brands and types of waterproofing materials to find one that best suits your needs.

When you’re done your surface will be waterproof.

Applying the waterproofing material

Understanding the process is crucial to achieving top-quality results when it comes to waterproofing. Whether you’re working on a deck, balcony, or bathroom, there are some key differences to remember.

  • For balconies, polyurethane and epoxy products are commonly used. These products may have strict working times and can be one or two components. The material is applied to the surface, creating a waterproof barrier that protects against the elements.
  • Bathrooms, on the other hand, require a slightly different approach. Before applying the waterproofing membrane, mesh reinforcements are often installed around corners and drainages to provide extra strength and durability. This helps prevent leaks and ensures that the bathroom remains dry and functional for years.

You can ensure your waterproofing project succeeds by understanding these differences and following the appropriate steps.

  • To ensure that your waterproofing project is successful, following the manufacturer’s instructions is essential. The instructions provided will give you the best result possible.
  • If you have purchased a waterproof system package, following the drying times between coats or installing reinforcement meshes is essential. These times are set to ensure that the material has enough time to dry and cure properly.
  • Before applying the first coat, it is essential to determine the area you will work on. This will help you plan how much material you will need and help you create clean lines between walls and floors.

If you are, for example, working on a balcony, use painter’s tape to create a clean line between the wall and the floor. However, suppose you are using something like epoxy or polyurethane coating.

In that case, it is crucial to remove the tape immediately, as it will cure into a layer of rubber and won’t come off clean once the surface is walkable.

  • If necessary, apply additional coats of waterproof material. Some balconies and decks require a certain thickness of waterproof material to ensure proper protection.

Applying more coats can also help hide any imperfections on the bottom layer. It is important to note that each coat must dry completely before applying the next one.

Applying a second coat before the first one has cured may cause the first coat to remain soft between the concrete and the coating top, while the second coat will insulate from curing well. This could result in floating water, which differs from what you want.

Allowing the material to dry completely is the most crucial step in the process. Although applying the second coating before the first one has cured may be tempting, this could lead to problems.

If you are using thicker layers of waterproof material, allowing each coat to dry completely is especially important. This will ensure that the material cures properly and provides the necessary protection.

The time it takes for the material to dry will vary depending on the type of material used. For two-component materials, the chemical reaction will cause the material to harden, and you will not need to wait as long for it to dry.


To ensure the longevity of your item, it’s essential to perform regular maintenance. Here are some detailed steps you can take:

  • Regular cleaning – Use a mild detergent and water to clean the item regularly. Avoid using harsh chemicals that may damage the material.
  • Inspect for damage – Check the item regularly for any signs of wear and tear. Look for tears, rips, or holes and address them immediately to prevent further damage.
  • Reapply waterproofing material as needed – Over time, the waterproofing material on your item may wear off. To prevent damage from water, reapply waterproofing material when necessary. Follow the manufacturer’s instructions for the best results.


We have delved into the various waterproofing methods and the significance of preparing the surface to achieve the ultimate results, whether through epoxy coating or floor tiles. A crucial factor to consider is that the concrete floor should be level and tilted appropriately to ensure proper drainage.

My final piece of advice would be always to scrutinize your work. For instance, when working with balconies, I used to test the tilts with a final wash before coating.

This method would involve checking if any water puddles formed, which would determine the work’s success. Similarly, I have always relied upon a bubble level to ensure the floor is leveled correctly when dealing with bathroom floors.

However, it is essential always to double-check your work to eliminate any potential harm. This approach ensures that when you move to the next step, you are confident that it has a solid foundation to succeed.