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April 16, 2024

What Causes Basement Leaks?

What causes basement leaks h&n basement worx

Basement leaks typically stem from a few common causes:

Cracks in Foundation/Walls

Cracks in the foundation walls or floor are one of the most common entry points for water. As concrete ages and settles, small cracks and gaps can form. Hydrostatic pressure from soil moisture can drive water through these cracks into the basement. Cracks as small as 1/16th of an inch can allow significant water intrusion over time.

Poor Perimeter Drainage

Inadequate drainage around the exterior foundation walls is another major cause of basement leaks. If rainwater or snowmelt can’t drain away from the basement perimeter and saturates the soil, it can seep through small cracks or pores in the concrete. Proper grading to slope the soil away from the home and a functioning gutter system are important.

High Groundwater Table

A high groundwater table means the level of subsurface water is close to the basement floor. During rainy periods, the groundwater can rise and exert hydrostatic pressure, leading to leaks along cracks, joints, or pores. In extreme cases, water may even come up through the floor.

Damaged Waterproofing Membranes

Waterproofing coatings, membranes, or drainage boards applied to the exterior of foundation walls can fail over time. If these barriers become damaged or degraded, water can intrude into tiny gaps and penetrate the walls. Older homes may have little or no waterproofing installed.

How to Locate the Source of Basement Leaks

The first step in repairing a leaky basement is identifying where the water is coming from. Here are some tips for locating the source:

  • Observe the basement during heavy rainfall. Look for active leaks and note where water is dripping or seeping in. Water trails or stains on the walls and floor can also indicate flow patterns and pinpoint problem spots.
  • Use a garden hose to simulate rainfall and test different areas. Focus on foundation walls, joints between walls and floor, windows, and the floor-wall seam. Move methodically around the basement, spraying water to isolate the leak location.
  • Check for cracks, gaps, and deterioration in the concrete or cinder blocks. These vulnerabilities allow water to seep in and are common sources of leaks. Inspect inside and outside foundation walls.
  • Consider hiring a professional home inspector if you are unable to find the leak source. Their expertise, specialized equipment like thermal imaging cameras, and underground drainage system checks can help accurately identify the issue.

Locating where water is entering is critical to determine the appropriate repair method to stop the leak at its source. Patience during the inspection process and thoroughness in checking all potential points of entry will help uncover the root cause of the basement water problem.

DIY vs Professional Leak Repairs

When it comes to repairing a leaky basement, homeowners have the option of doing it themselves (DIY) or hiring a professional contractor. The choice largely depends on the complexity of the job, types of repairs needed, cost comparison, time requirements, and your experience level.


Minor leaks from simple cracks or holes can often be repaired by handy homeowners. However, extensive water damage or leaks stemming from foundation issues should be left to the pros. If multiple sources of leakage are present or the cause is unclear, professional assessment is recommended.

Types of Repairs

Basic DIY repairs include sealing cracks, patching holes, applying waterproof paints or coatings, and installing drainage systems. More complex repairs like structural foundation work, excavating and waterproofing outside foundation walls, or installing sump pump systems are best left to professionals.

Cost Comparison

DIY repairs cost a fraction of professional repairs in materials only. However, mistakes can be costly. Professionals have high labor costs but get the job done right the first time.


DIY projects take more time with the learning curve. Professionals will repair your basement efficiently and quickly.

Experience Level

Handy homeowners may be able to do basic repairs successfully. Professionals have years of experience, the right tools and materials, and can provide warranties for peace of mind.

In summary, DIY repairs are ideal for minor leaks but professionals are recommended for extensive water damage or foundational repairs. Consider the level of complexity and your skillset when deciding between DIY or hiring a contractor.

What Are The Best Basement Waterproofing Methods?

There are several basement waterproofing methods to address leaks from the inside or outside of your home.

Interior Drainage

Interior drainage systems use perforated pipes installed underneath the basement floor to collect water and direct it to a sump pump. The sump pump then ejects the water away from the foundation. Interior systems are less disruptive as they don’t require excavating the foundation from the outside.

Exterior Drainage

Exterior drainage involves digging along the foundation to waterproof the outside foundation walls. Drain tile, gravel, or perforated pipe is installed to divert groundwater away from the basement. Exterior drainage is more effective for stopping heavy water flow.

Sealants and Coatings

Applying waterproofing sealants or coatings to the interior basement walls can help seal cracks and prevent moisture penetration. Epoxy injections can also be used to fill foundation cracks. Sealants provide a cost-effective DIY solution but may not stop major leaks.

Sump Pumps

A sump pump collects water pooled in the sump basin and pumps it away from the home. Sump pumps are essential for both interior and exterior drainage systems. Battery backup sump pumps provide protection in case of power failure.

Vapor Barriers

Vapor barriers such as plastic sheeting prevent moisture from seeping through concrete basement walls. Vapor barriers can be installed on top of the soil underneath a basement subfloor.

Foundation Repairs

For severe foundation cracks and leaks, foundation repairs like a crack stitching process may be needed. Steel support beams can also be installed to stabilize bowed or sinking foundation walls. Professional structural engineers are required for major foundation repairs.

Preventing Future Leaks

To prevent future basement leaks after repairs have been made, there are several maintenance tips to follow:

Proper Drainage

Ensuring proper drainage around the perimeter of your home is crucial to prevent water from pooling near the foundation. Make sure downspouts direct water at least 5 feet away from the home’s foundation. Grade soil so it slopes at least 6 inches over 10 feet to promote drainage away from the house. Fill any low spots or depressions near the foundation with dirt.

Regular Inspections

Inspect your basement walls and floor during heavy rains to catch any new leaks early. Look for cracks, seepage, musty smells, or moisture on walls and floors. Checking for leaks during the rainy season can help you address problems before major damage occurs.

Crack Maintenance

Inspect foundation cracks periodically, especially after extreme weather. Re-apply sealants or caulking as needed to maintain waterproofing on existing cracks. Watch for new cracks and repair promptly.


Proper ventilation helps control humidity and moisture in the basement. Use exhaust fans, open windows when possible, and consider installing dehumidifiers to maintain optimal moisture levels.

Gutter Maintenance

Clean gutters regularly and check downspouts for proper drainage. Clogged gutters can lead to overflow and water intrusion through the foundation or walls.

With diligent maintenance and routine inspections, future basement leaks can be prevented or caught early before causing major headaches. Address any water intrusion promptly and utilize professional waterproofing services as needed.


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