Everything You Need to Know About Basement Waterproofing


Waterproofing a basement is one of the best ways to prevent excess moisture from damaging a home. It can involve the installation of an interior French drain or a sump pump. Still, it can also be as simple as correcting the exterior grading of the property so that water drains away from the foundation and basement underpinning.

What is Basement Waterproofing?

Waterproofing is more than just coating your basement walls and floors. It’s a range of preventative and reactive techniques designed to keep runoff and groundwater away from your foundation walls, remove any moisture that does get inside, and help your home drain better when it rains.

The outermost ring involves the soil surrounding your house: proper grading to direct runoff away from the foundation, gutters, downspouts, window well covers and more. Incorrect grading can cause soil to collect against the foundation, elevating hydrostatic pressure that can force water through cracks or porous concrete.

The middle ring includes the exterior of your home itself, including the basement walls and floors. This involves fixing issues that could lead to water leaks or intrusions, such as repairing cracked basement walls and floors. It also involves installing proper drainage systems, such as French drains (a trench lined with gravel and a perforated pipe that diverts water) or a water tunnel system. These exterior methods are considered preventative because they stop the water before reaching your basement walls.

What are the Benefits of Basement Waterproofing?

Basement waterproofing protects your home from the damage and expense of water intrusion. It also helps create a healthier indoor environment, as excessive moisture can lead to the growth of mold and mildew. These harmful organisms can cause asthma, hay fever and other conditions. Waterproofing can also reduce your heating and cooling costs by eliminating dehumidifier needs.

A professional basement waterproofing contractor can install an exterior membrane to stop water infiltration. This can be a more effective solution than sanding down the walls or painting with foundation paint. Neither technique can fully protect your basement against deep moisture or hydrostatic pressure from the soil.

The outermost ring of your house includes the yard and garden, gutters, downspouts, drain tiles, window well covers and swales. The middle ring comprises your house’s perimeter wall, floor drains and sump pump (if you have one). The inner ring includes the basement itself. Problems in this zone include

  • Poorly graded soil that sends water toward the house.
  • Missing or blocked gutters and downspouts.
  • Overflowing or clogged French drains and damaged basement windows.

How Does Basement Waterproofing Work?

If your basement is damp or you see mold growth, it’s time to call a professional. Untreated moisture problems can damage your home’s foundation, cause wood rot and even affect indoor air quality. They can also devalue your house and increase repair costs over time.

Waterproofing professionals employ various techniques to ensure your basement is free from moisture. Many of these methods are not quick fixes like interior paint or epoxy injections but long-term solutions designed to solve the root of the problem.

Moisture in the soil under your house can get through cracks in your basement walls or floors. It can also move through solid concrete walls using capillary action. Inadequate drainage is another common source of wet basements. Rainwater not properly directed away from your house can pool at your basement wall, causing leaks. It can also seep into your basement through egress windows and window wells that aren’t sealed. Waterproofing can address all of these issues.

In most cases, installing an interior drainage system is the best way to waterproof a basement. This involves digging a trench along the interior of your basement floor and adding a series of hidden drainage channels to capture water from leaks in your walls and where the basement floor meets the walls. The water is then diverted to a sump pump pit, which pumps it outside your house.

What Are the Costs of Basement Waterproofing?

Waterproofing costs can vary significantly depending on how much work your basement needs. The best way to minimize upfront costs is to do finishing work, such as hanging drywall or installing flooring after the basement has been waterproofed. That way, you can ensure the drywall and floors are dry before investing in expensive furniture or painting.

Generally, the most expensive basement waterproofing method is installing exterior weeping tiles, French drains or membranes around your home’s foundation walls. This usually requires excavation and may cost up to $15,000.

Another option is damp proofing, which fights soil moisture from soaking into concrete. It’s often cheaper than a full waterproofing solution, but there are better solutions for most homes in flood-prone areas.

Waterproofing your basement is a worthwhile investment for many reasons. Not only will it prevent mold and mildew from growing, but it also adds value to your home and can help you sell it faster if you ever decide to move. It also saves on energy bills because humid air makes your HVAC system work harder to heat and cool your house.

How Can I Know if My Basement Needs Waterproofing?

Moisture in the basement is a common problem that can lead to wood rot, structural damage to the house and poor indoor air quality. While some signs of moisture in the basement are obvious, others may be less.

Water stains on the basement floor or walls indicate groundwater is entering the home. These stains can occur for several reasons, including a spill or washing machine leak. However, if the stains are old or faint, they may indicate that water has been seeping through the foundation for some time.

If the stains have been there for a while, they can lead to other problems, such as mold and mildew, wood rot and crumbling concrete. Waterproofing is an ideal solution to prevent future water intrusion. Other moisture control measures include removing foundation plantings, ensuring that gutters and downspouts work properly, and waterproofing window well covers. Moisture originating from the inside of the house can be controlled by equalizing water and air temperature to prevent condensation, running dehumidifiers and repairing leaky pipes.