How to Waterproof a Basement

How to Waterproof a Basement

If you have consistent water problems in your basement then you might need to look into some waterproofing techniques to keep your basement dry. Even a small leak can lead to mold and possibly even structural damage to your home, so it’s important to take steps to prevent it. Keep reading to learn how to waterproof a basement.

Proper Exterior Grading 

Ideally you want the land around your basement to slop away from the house. This directs water away from the foundation and is often the best defence against leaks.  Over time though soil can wash away or the area may have never been landscaped properly in the first place. Poor exterior grading can cause water to collect and pool against the foundation walls, which will inevitably lead to leaks. Make sure you have a slope of at least 6-8 inches away from the foundation walls, extending for the first 6-8 feet.

Paved surfaces that are adjacent to your house may also be causing water leaks. In fact, they are even more problematic because they shed water so quickly. Check to see that any paved surfaces slope away from your house. Any open gaps in driveways, walkways and patio slabs near the foundation walls should be patched as well to prevent water from pooling underneath.

Even if you have proper grading around your basement water might still be pooling around your foundation. If there are bumps or ridges surrounding your basement they may not be allowing water to flow over them and causing it to flow back towards your house. Ensure that your grading system is working properly and water is flowing away from your house like it’s supposed to by taking a physical observation when it rains or by running a hose lightly around the landscape.

Optimize Your Gutter System

Gutters are an essential part of a proper drainage system. If they don’t work correctly it can force water to run off the roof and collect around your foundation. The area surrounding your foundation, known as the excavation ring, is generally packed looser than other areas of your property. Because of this you want to keep water away from this area. Ensure that your gutter extensions extend past the excavation ring and replace any leaking or rusted gutters. Also, remember to clean your gutters regularly to prevent any clogs.

Remove Plant and Shrub Overgrowth

Shrubs may help make your property look more attractive, but believe it or not they can also cause basement leaks. Water can follow the roots of shrubs planted close to the foundation walls and flow towards your house’s foundation. Make sure all plants and shrubs are planted an appropriate distance away from your house.

Interior Waterproofing

The best way to waterproof your basement is from the outside, but interior waterproofing can be a quick and simple alternative. If you have small, intermittent leaks then applying some sealant or a waterproofing solution to your basement’s walls may be all that is necessary. There are three types of interior waterproofing and you will have to choose the right product for the type of walls in your basement.

  • Concrete Waterproof Coating: This type of waterproofing is ideal for concrete or masonry walls and can’t be applied to painted surfaces. Use a heavy brush made with tampico bristles to apply the coating.
  • Silicate-Based Concrete Sealers: Only apply this waterproofing solution to walls that haven’t been painted or sealed. You can use either a brush or roller to apply the sealer, or you can spray it on. Once applied it will soak into the concrete or brick and create a waterproof surface. Usually these types of sealers can be painted over if you so choose.
  • Waterproofing Paint: This product is very similar to ordinary wall paint except that it needs to be applied much thicker. Use waterproofing paint for painted surfaces. Brush, roll, or spray  the paint on, using one gallon to cover 75 square feet (instead of the 300 square feet typical of standard paint).

Repair Cracks

Walk around the outside of your house and look for any cracks in the wall of your basement. If you spot any the first thing you should do is call a structural engineer or a foundation specialist to schedule an inspection. Cracks can do more than just let water in; they can compromise the structural integrity of your home, so make sure there are no serious problems before moving on

Assuming the cracks aren’t serious the next step is to patch them up. Deep cracks that go all the way through the wall are one of the most common causes of leaks, so you’ll want to take care of these. To repair a crack, follow these steps:

  1. Clean the area and get rid of any loose chips.For stubborn debris use a small sledgehammer and a cold chisel to remove it.
  2.  A vinyl concrete patch is a good choice for fixing cracks in your foundation. Mix the patch to the consistency of a thin paste and add latex instead of water to give it some added elasticity and adhesion. Don’t mix too much at once, as these products tend to dry quickly.
  3. Wet the crack with water before installing the patching product. This will prevent the moisture in the patch material from being drawn out by dry concrete, which can prevent the patch material from forming a solid bond and lead to cracks.
  4. Use a trowel to smooth out the patch material and level it with the walls of your foundation.

Install a French Drain

For serious water problems you might want to consider installing a French drain. This is a drainage system that consists of a continuous system of piping, running beneath the floor of the basement and along the entire perimeter of the basement. The pipe is surrounded by coarse gravel and is perforated to let water inside. The water is then removed by a sump pump. For more information on how to install a French drain, click here.

Inject Hydroclay Around Your Foundation

Hydroclay injection can be a very effective waterproofing technique, but it’s not really a DIY job, so you’ll likely need to hire a professional. The clay is pumped into the voids and pathways water uses to get inside your foundation to keep your basement dry. Hydroclay’s excellent water absorption abilities means it draws water in and helps seals your basement from the outside.


- Debug: cached@1484651960 -->