how to waterproof a basement

How to Waterproof a Basement: A Comprehensive Guide


Basement waterproofing is essential for maintaining the structural integrity of your home and preventing costly water damage. In this article, we will guide you on how to waterproof a basement. It will help you with keeping your basement dry and safe.

Understanding the Need for Waterproofing

The primary reason to waterproof your basement is to prevent water from seeping through the foundation walls, which can lead to mould growth, structural damage, and a decrease in property value. Waterproofing is especially crucial in areas prone to heavy rainfall or with high water tables.

Exterior Waterproofing Process

  1. Inspection and Preparation: The first step is to thoroughly inspect the exterior basement walls. Look for cracks or signs of moisture penetration. The area around the basement should then be excavated to expose the foundation walls.
  2. Cleaning and Repair: Once exposed, the walls should be cleaned to remove dirt and debris. Any visible cracks should be repaired using hydraulic cement or other suitable materials.
  3. Applying Waterproof Coating: The next step is to apply a waterproof coating to the exterior walls. This can be a liquid rubber membrane, a bituminous coating, or any other waterproofing material designed for exterior use. Ensure that the application is even and covers the entire surface.
  4. Drainage System Installation: A proper drainage system, such as a French drain or weeping tiles, should direct water away from the foundation.
  5. Backfilling: After drying the waterproofing material, the excavated area should be backfilled carefully. The soil should be compacted to avoid any future settling.

Advantages of Exterior Waterproofing

  • Long-Term Solution: Exterior waterproofing is durable and can last for decades.
  • Protects Structural Integrity: It prevents water from entering through the foundation, thereby protecting the structural integrity of the building.
  • Increases Property Value: A waterproofed basement is a valuable asset that increases your home’s marketability and value.

Adding Interior Waterproofing to Your Basement Protection Strategy

While exterior waterproofing is crucial to protecting your basement, complementing it with interior waterproofing methods can provide an additional layer of defence against moisture in the basement. Here’s how interior waterproofing can be implemented:

  1. Interior Sealants and Coatings: The first line of defence in interior waterproofing involves applying sealants and waterproof coatings to the basement’s interior walls. These sealants can prevent minor dampness and keep humidity levels in check. They are particularly effective for concrete walls, blocking water vapour transmission.
  2. Interior Drainage Systems: An interior drainage system, such as a perimeter drain or a French drain installed inside the basement, can be highly effective. This system collects any water entering through the walls or floor and channels it away, typically to a sump pump. The sump pump then expels the water safely away from the foundation.
  3. Sump Pump Installation: A crucial component of interior waterproofing, a sump pump removes accumulated water from the basement. It’s typically installed at the lowest point of the basement floor. Regular maintenance and testing of the sump pump are essential to ensure it functions correctly, especially during heavy rainfall.
  4. Dehumidifiers: Using a dehumidifier in your basement can help manage the moisture level, preventing mould growth and creating a healthier environment.

Benefits of Interior Waterproofing

  • Cost-Effective: Generally, interior waterproofing is less expensive than exterior waterproofing and can be a more feasible option for many homeowners.
  • Less Invasive: This method doesn’t require excavation around the house, making it less disruptive to your daily life and the landscape.
  • Addresses Hydrostatic Pressure: Interior systems help alleviate the pressure that can build up from water in the soil surrounding the foundation, reducing the risk of cracks and leaks.

How To Waterproof a Basement: Combining Exterior and Interior Waterproofing

For optimal protection, combining both exterior and interior waterproofing methods is recommended. This dual approach ensures your basement remains dry and secure from outside and inside water sources.

Understanding and implementing exterior and interior waterproofing techniques ensures a comprehensive approach to keeping your basement dry and free from water damage. This holistic strategy not only safeguards your property but also enhances the comfort and usability of your basement space.

Maintenance and Care

Regular maintenance, such as cleaning gutters and inspecting the foundation for cracks, is crucial for the longevity of your waterproofing system. Annual inspections by professionals can also help identify and address potential issues before they escalate.


In summary, effectively waterproofing your basement is vital to protecting your home’s foundation and enhancing its value. Whether you choose exterior waterproofing to prevent water seepage or interior methods to control moisture, each approach offers unique benefits. Regular maintenance and occasional professional checks are crucial to ensure the longevity and effectiveness of your chosen waterproofing system. Adopting appropriate waterproofing strategies allows you to maintain a dry, comfortable, and usable basement space, thereby securing your investment in your home’s health and safety for the long term.