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A Comprehensive Guide to Basement Waterproofing in Toronto Introduction | 2023

A wet basement can cause significant damage to your home, especially in areas like Toronto, where heavy rainfall and melting snow can pose serious threats. The key to maintaining a healthy, dry basement lies in proper waterproofing techniques. In this guide, we’ll cover essential steps to waterproof your basement walls and safeguard your home from water-related damage. We’ll also provide practical tips for preventing basement moisture issues in Toronto homes.

Table of Contents

Understanding the Causes of Basement Moisture

Before diving into the dos and don’ts of basement waterproofing in Toronto, it’s crucial to understand the common causes of moisture in basements. Some of the main sources of basement water intrusion include:

  1. Cracks in basement walls and floors: As your home settles over time, cracks can form in your basement walls and floors, allowing water to seep in.
  2. Poor drainage: Insufficient or poorly maintained gutters and downspouts can cause water to accumulate near your foundation, increasing the risk of basement moisture issues.
  3. Ineffective grading: If your yard slopes towards your home, water can pool around your foundation and eventually infiltrate your basement.
  4. Window well leaks: Window wells without proper drainage systems can retain water, leading to basement leaks.
  5. Hydrostatic pressure: The pressure exerted by water-saturated soil against your basement walls can cause water to seep through even structurally sound walls.
Basement wall with visible water seepage and cracks in need of waterproofing in Toronto
Basement wall with visible water seepage and cracks in need of waterproofing in Toronto

Basement Waterproofing Dos and Don'ts

To effectively waterproof your basement walls and prevent moisture-related damage, follow these essential dos and don’ts:

DO Identify the Source of Water Intrusion

Before taking any waterproofing measures, it’s crucial to determine where the water is coming from. Look for wet streaks along cracks, at the corners of windows, between mortar joints (for cement block walls), and around pipes where they enter or exit, such as a water-supply line or a sewer pipe.
To conduct a simple condensation test, dry an area of the wall with a rag, and then attach a 1-foot square piece of aluminum foil to the wall with duct tape. Peel off the foil after 24 hours and check the underside of the foil. If it is wet, water is seeping through the wall from the outside. If dry, the moisture is originating elsewhere in the basement, likely from a basement shower. In that case, install a vent fan in the bathroom to direct steam outdoors.

DON'T Make Wall Repairs with Standing Water in the Basement

During a rainy season or periods of heavy snowmelt in Toronto, water can seep into your basement through cracks or other vulnerabilities. Before repairing any cracks or addressing other waterproofing needs, remove all standing water from your basement. This step is crucial for ensuring your safety, as working in a flooded basement increases the risk of electrical shock or electrocution. Turn off the power to the basement, and then use a utility pump to remove the water.

DO Seal Cracks with Hydraulic Cement

To address cracks in your basement walls, fill them with hydraulic cement, such as QUIKRETE’s Hydraulic Water-Stop Cement. Hydraulic cement contains additives that cause it to expand and set rapidly, forming a watertight bond within cracks and crevices. Mix only as much cement as you can use within three minutes to prevent it from setting too quickly.

Professional applying hydraulic cement to repair foundation cracks in a Toronto basement
Professional applying hydraulic cement to repair foundation cracks in a Toronto basement

DON'T Forget to Address Window Well Leaks

If your basement window wells lack proper drainage systems, they can retain water, leading to leaks. Consider digging approximately 2 feet lower in the well area and filling the space with gravel to help rainwater disperse rather than collect in the window well. Caulk around the window with a masonry-compatible caulk, such as GE’s 100 Percent Waterproof Silicone All Purpose Caulk. Additionally, install a sloped window well cover, like Shape Product’s Universal Fit Polycarbonate Window Well Cover, to direct rainwater away from the well.

Toronto homeowner installing a window well cover to prevent water leaks in basement

DO Apply Masonry Waterproofing Products to Bare Interior Basement Walls

If your condensation test shows that water is soaking through your basement walls, seal the interior walls with high-quality waterproof paint, such as DRYLOK White Extreme Waterproofer. This premixed sealant is applied like a coat of paint, filling all the small surface holes. Allow it to dry fully before applying a second coat. When completely dry, the sealant forms a watertight bond, preventing moisture from seeping through.

Expert applying masonry waterproofing paint to interior basement walls in Toronto home
Expert applying masonry waterproofing paint to interior basement walls in Toronto home

DON'T Apply Sealer Over Painted Walls or Efflorescence

Before applying a waterproofing sealant, remove any existing paint on the basement walls, as the sealer adheres best to bare masonry. In older homes, multiple coats of paint may need to be removed by sandblasting or wire brushing. Additionally, remove any efflorescence (white deposits that form on the surface of concrete walls exposed to constant moisture) with muriatic acid, following the manufacturer’s instructions.

Tips for Preventing Basement Moisture Issues in Toronto Homes

In addition to waterproofing your basement walls, take these steps to keep water away from your basement and reduce the risk of moisture problems:

  1. Remove foundation plantings and flowerbeds that require watering, as the water can seep into the basement.
  2. Inspect and, if needed, repair gutters and downspouts to ensure they direct water away from your home.
  3. Grade your yard away from the foundation with at least a 2 percent slope.
  4. Consider installing an exterior drain tile system, a perforated drain at the footing level with a waterproof membrane on the outside of the basement wall. While costly, this solution can significantly reduce basement water issues.
  5. Don’t forget about interior drainage solutions, such as installing a drainage channel beneath the floor inside the basement. This method, while expensive, results in new, dry walls and directs residual water seeping through the old basement walls to the drain channel and pumps it away.
Exterior drainage system installation around a Toronto house foundation for basement waterproofing.

Case Study: Basement Waterproofing in Toronto Home


The homeowners, John and Jane, live in a 30-year-old home in Toronto with a finished basement. Over the years, they noticed an increasing problem with dampness and water seepage in their basement, particularly during the rainy season. They decided to address the issue and contacted a local basement waterproofing company in Toronto for a thorough assessment and recommendations.


Upon inspecting the basement, the waterproofing experts discovered several issues contributing to the water problems:

  1. Cracks in the foundation walls, allowing water to seep in.
  2. Inadequate grading around the house, causing water to pool near the foundation.
  3. A damaged window well that allowed water to enter the basement.
  4. Poor interior ventilation, resulting in high humidity levels.

The homeowners wanted a comprehensive solution to address these issues and prevent future water damage in their basements.


The basement waterproofing company proposed a multi-step plan to address the identified issues:

  1. Repair the foundation cracks using hydraulic cement to create a watertight seal.
  2. Install an exterior drain tile system to redirect water away from the foundation and prevent seepage.
  3. Improve the grading around the house to ensure water flows away from the foundation.
  4. Replace the damaged window well, install proper drainage, and seal the window with masonry caulk.
  5. Apply a high-quality masonry waterproofing product to the interior basement walls to prevent moisture intrusion.
  6. Install a dehumidifier and proper ventilation to reduce humidity levels in the basement.

The homeowners agreed to the proposed plan, and the waterproofing company completed the project within the agreed-upon timeframe and budget.


Following the completion of the waterproofing project, John and Jane observed significant improvements in their basement’s condition. They no longer experienced damp walls, standing water, or mold growth. The humidity levels were reduced, creating a more comfortable and healthier living space. As an added benefit, they noticed a reduction in their energy costs due to the improved insulation and air quality.

The homeowners were highly satisfied with the outcome and could now fully enjoy their dry and comfortable basement without worrying about potential water damage. This case study highlights the importance of addressing basement waterproofing issues in a timely manner and working with a reputable professional in Toronto to achieve the best results.


By following these essential dos and don’ts and implementing the practical tips provided, you can effectively waterproof your basement walls and prevent moisture-related damage to your Toronto home. Proper basement waterproofing is a critical investment in the long-term health and safety of your home, ensuring a dry, comfortable living space for years to come.

Basement Waterproofing FAQ

Most frequent questions and answers

The cost of basement waterproofing in Toronto varies based on the size of your basement, the extent of the problem, and the chosen waterproofing method. On average, homeowners can expect to spend anywhere from $3,000 to $15,000 or more. It’s essential to consult with a professional waterproofing service to get an accurate estimate tailored to your specific situation.

The longevity of basement waterproofing in Toronto depends on the materials used and the quality of the workmanship. Generally, professionally installed interior waterproofing methods can last up to 10 years or more, while exterior waterproofing methods can last up to 20 years or longer. Regular maintenance and prompt repair of any issues can help extend the lifespan of your waterproofing system.

While some minor waterproofing tasks can be done as DIY projects, it’s highly recommended to hire a professional for more complex issues. Professionals have the necessary tools, materials, and expertise to ensure a high-quality, lasting waterproofing job. They can also help identify the root cause of the problem and recommend the most effective solution for your specific situation.

Some common signs that your basement may need waterproofing include:

  1. Damp or wet walls
  2. Standing water or puddles on the floor
  3. Mold or mildew growth
  4. Musty odors
  5. Efflorescence (white, chalky deposits) on walls or floors
  6. Cracks in walls, floors, or the foundation

If you notice any of these signs, it’s crucial to consult a professional waterproofing service in Toronto to determine the best course of action.

Yes, waterproofing your basement can help reduce energy costs in your Toronto home. By sealing your basement walls and preventing moisture intrusion, you can improve insulation and reduce heat loss. This can help maintain a more consistent temperature in your home, resulting in lower energy bills. Additionally, a dry and well-ventilated basement can help prevent mould growth, which can contribute to improved indoor air quality and a healthier living environment.


More about Basement Construction in Toronto:

  • Toronto
  • Etobicoke
  • Mississauga
  • East York
  • North York
  • Leaside
  • Scarborough
  • Vaughan
  • Oakville
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