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How Poor Foundation Drainage Causes Basement Damage

water in basement from bad drainage

Water damage can have severe consequences for your home, particularly on the foundation—the structural base that keeps your house intact. Excessive moisture can cause the foundation to deteriorate, leading to potential structural damage.

The root issue of poor foundation drainage is the misdirection of water around your home. The soil adjacent to and beneath your foundation isn’t firm; its condition changes with its water content—it can wash away, expand, contract, or become compact. This fluctuation is especially problematic around your basement foundation where excess water in the soil triggers hydrostatic pressure.

Hydrostatic pressure exerts additional weight against basement walls, leading to cracks and subsequent water leakage and pooling around your basement and foundation. Understanding what causes poor foundation drainage is crucial to solving this problem and protecting your home.

Here’s everything you need to know. 

What Causes Poor Foundation Drainage? 

Here are the main causes of poor foundation drainage:

  • Clogged Gutters: These are critical in preventing water accumulation around your home. If not maintained properly, especially during fall when leaves clog them, water can pool around your property.
  • Downspouts: If these don’t direct water far enough away from your home, the soil can absorb it and cause problems.
  • Negative Lawn Grade: A positively graded lawn diverts water from your home, while a negatively graded one allows water to collect around it. If your lawn is negatively graded, consider having it professionally adjusted.
  • Basement Windows and Window Wells: Over time, basement windows can deteriorate, allowing water and humidity to enter. Window wells help prevent this, but if they are damaged, leaks can occur.
  • Damaged Sump Pumps: These devices drain water from basements. If damaged, they cannot perform this task effectively. Regular issues may require consultation with a contractor.
  • Expansive Soil: In places like North Carolina, the common Cecil soil expands when wet and shrinks upon drying, leading to denser soil with cracks and gaps that let in water. As the soil loses its topsoil, your home’s foundation can settle and crack, allowing more water seepage.
  • Inadequate Waterproofing: Despite the rise of basement waterproofing, traditional methods often fall short. As water can seep through even concrete, comprehensive waterproofing methods, including an interior drainage system, sump pump, dehumidifier, and vapor barriers, are crucial in preventing poor foundation drainage, especially in flood-prone areas.

What Can Be Done About Poor Foundation Drainage? 

Poor foundation drainage can end up destroying your home and costing you a lot of money in the long run. Thankfully, there are multiple things that can be done in order to repair and prevent the consequences of poor foundation drainage.


To prevent poor foundation drainage, basement waterproofing is key. Even with an existing external drainage system, an additional internal system can provide extra protection, reducing costs and headaches. Here are some effective waterproofing methods:

  • Interior Drains: These are placed around the basement’s perimeter, under the floor, to intercept any infiltrating water. The collected water drains into a sump pump system for removal.
  • Sump Pump: This device mechanically pumps out water from the basement, working in tandem with the interior drain. It automatically manages water, preventing basement flooding.
  • Vapor Barrier: Typically used in crawl space encapsulations, a robust vapor barrier on basement walls can also prevent moisture and vapor intrusion.
  • Dehumidifier: By maintaining low humidity levels, a dehumidifier prevents mold growth and discourages pests, protecting your basement’s contents.


To maintain the structural integrity of your home’s foundation, both interior and exterior waterproofing methods are necessary. Here are some effective outdoor solutions:

  • Yard Re-grading: If heavy rainfall turns your property into a moat-like scene, re-grading your yard is essential. This involves adjusting the ground to create a downward slope, leading rainwater away from your home, not towards it.
  • Downspout Adjustment: Downspouts should direct water away from your home. If they’re pointing towards your house, they need repositioning. Extending downspouts can help drain water further from the foundation, preventing soil swelling and shrinking near the foundation that could damage the home’s structural base.
  • Window Wells: Window wells act as a protective shield between your basement windows and soil, preventing window damage from expansive soil. These small trenches often have built-in drainage systems to avoid water accumulation. They come in a variety of designs to match your home’s aesthetic.
  • Exterior Discharge Line Modifications: For homes with sump pumps, altering the discharge line can improve water drainage from the foundation. Reputable contractors can install attachments like FreezeGuard™ that ensure continuous water drainage, even when the discharge pipe is frozen or blocked.
  • Exterior French Drain: An exterior French drain is a gravity-dependent drainage system. Installed within a gravel-encased trench, this pipe directs water away from your home, similar to an interior drain but exclusively outdoors.
puddles in yard

Poor Foundation Drainage FAQs

The biggest argument for foundation drainage repair and basement waterproofing is hydrostatic pressure. It’s something many homeowners may not be aware of because it has to do with the water content within the foundation’s soil. It’s something that homeowners aren’t able to detect until it’s already too late, and the only way to avoid it is by properly waterproofing your basement and making sure the drainage system is functioning properly. 

How It Works 

Soil, especially expansive soil, is capable of collecting and holding large amounts of water. You might not think it, but water can actually be extremely heavy. If your house does not have a proper foundation drainage system, a lot of water will begin to collect underneath the soil. 

However, it’s not just underground water that puts pressure against the walls of your basement. Any water that sits atop your yard will increase the hydrostatic pressure and make the situation worse. This is why it’s important to waterproof your basement as well as make all the necessary alterations to your outdoor drainage system. 

How it Affects Your Home 

Because of how heavy the water is, it will place a large amount of pressure on the walls of your basement. Despite how strong concrete seems, it’s no match against the force of water. It will begin to bow inward and will eventually crack. 

Cracked basement walls are a huge issue. The more cracks there are, the more frequently you’ll have to deal with leaks. If your basement walls are cracked because of hydrostatic pressure, you can bet that there is a lot of water pushing against your basement just waiting to get through.

How do you know your home is suffering from poor foundation drainage? It’s important to deal with the problem before the damages get too expensive or ruin the quality of life in your own house. Even if the drainage issues have caused some sort of damage around your property, repairs can still be done and prevention methods can be put into place before things get worse. Here’s everything you need to know to detect the problems: 

  • In the Home 

You’ll notice when there’s a drainage issue in your yard from within your own home. Because poor foundation issues affect the basement, you’ll be able to tell based on the mold growth, leaking, flooding, and humidity within the basement. If the drainage issues are really bad, your entire house will be inundated with the uncomfortable smell of humidity, and mold might even begin to grow in other areas of the house. 

Poor foundation drainage affects your soil, and when soils shrink or erode due to exposure to excess moisture, settling occurs soon after. Because of foundation settling, you might notice that your window and door frames are warped, cracked, or tilted. 

  • Outside the Home  

After some rain, it’s normal for the soil to be moist. However, there shouldn’t be large, deep puddles in your yard. With a proper drainage system in place and a positive yard grade, whatever puddle that forms should be gone in a few hours if there is sufficient sun. Significant paint peeling near the bottom half of your home is another sign to take note of. 

Settling concrete is another sign of poor foundation drainage. When the soil underneath your concrete steps, patio, or driveway is expanding and swelling, it will no longer be capable of supporting your concrete. All concrete settles over time, but if the concrete around your home shows significant signs of settling despite being covered, it could have to do with foundation drainage problems. 

One of the biggest threats to your home’s foundation drainage is expansive soil. As a matter of fact, it’s a threat to the entire structure of your house if you don’t take the necessary measures to prevent the damage. So, if expansive soil is that bad, why is it still used in construction, especially in a state like North Carolina, where the soil gets wet often? Turns out, expansive soils such as Cecil soil have their uses and are preferred by some site masters because of their properties. On some occasions, they might even make for a better foundation than other types of soils. 

  • Expansive Soil Properties  

While it is true that expansive soils tend to swell and shrink a lot, they compact better than any other soil. Soil that is to be used as a foundation must be compacted well so that it can be tough and dense. When properly compacted, expansive soils are firm, stable foundations. 

Because of these specific properties, many site managers prefer to use expansive soils. Other types of soils would have to be compacted multiple times before they are ready to be used as foundations. Because expansive soils compact so well, they are very easy to manipulate, which saves time during a construction job. 

  • Other Soils  

Other soils like gravel and sand have less clay in them, so they are less absorbent and don’t swell as much. As a result, they don’t shrink as much either. This might make them seem like the more attractive option as foundation soils, however, they have their downsides as well. 

Soils that don’t compact very well have a lot of air between each particle. Because of this, they are very loose and have a tendency to fall apart and give way when exposed to water or when there’s an earthquake. North Carolina may not get major earthquakes, but the earth is shaking with mini tremors all the time. Even though we don’t feel it, it does affect the ground significantly. 

Call Tar Heel Basement Systems for Basement Waterproofing and Repairs 

There’s a big difference between hiring a general contractor and relying on foundation repair experts to fix poor foundation drainage. Tar Heel Basement Systems specializes in basement and foundation repairs, and we’re proud to serve Winston-Salem and Raleigh, NC. We’re no jack of all trades, so we only work with the best tools in the industry for the job. Your property has never been in safer hands. 

If you’re having problems with your foundation and basement drainage system, don’t hesitate to get in touch with us. Contact us today to schedule a free inspection and repair estimate

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Michael Wilcher

Michael Wilcher

Michael Wilcher is the Content Lead at Groundworks, helping us to answer all of our customers biggest questions about foundation repair, basement waterproofing, crawl space encapsulation, and concrete lifting. In his free time, Michael enjoys collecting vinyl records, watching Formula 1 Racing, and reading philosophy. He holds an MPhil from the University of Cambridge.

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