Background image of cement blank wall.

There are several ways to waterproof your basement walls. Knowing how to waterproof the basement walls is cost-effective.

Of course, you expect your walls to be waterproofed during construction. But terrible original work can lead to seepage through the walls.

Poor original waterproofing can cause a lot of issues in the long run. And when not addressed quickly, the water damage can be tremendous. The problem may come from the outer walls or the inner walls. So trying to coat the inner walls when the real issue is from the outer walls can be a waste of time.


     1.Digging around the basement


To waterproof the walls, dig the outer perimeter of the basement until you reach the bottom of the foundation. This is not an easy task so you have to be prepared to work on the outer walls of the basement.

Waterproofing doesn’t just keep water out of the walls of your basement; it protects your pipes, paintwork, and insulation from water damage. 

After digging, you can install perforated pipes, crushed or gravel stone drains, drainage tiles, or any other waterproofing material or drainage system that works for you. 


     2. Block the cracks


Trowel with glove hand blocking wall crack

After digging the soils, clear the outer walls. Then you can see if there are holes or cracks where water can be seeping in. This means checking for porous areas, holes or hairline cracks in the inner and outer walls. To fix the hole problem, applying a coat of hydraulic cement is a great option. 

Hydraulic cement is capable of expanding and filling the cracks effectively.  


     3. Apply cement-based sealant


The next step involves applying a cement-based sealant to the exterior basement wall. Cement-based sealants work well for concrete or rock surfaces. Cement-based sealants get hard immediately and will cover the pores of the concrete surface. If a hole or a crack was not fixed properly with hydraulic cement, a sealant will finish the job.


     4. Installing a waterproof membrane

Next, you can spray or trowel a waterproofing membrane—for example, an asphalt-modified polyurethane material—on the outside wall of the basement. This membrane is designed specifically to act as a vapor membrane. These membranes are capable of moving and flexing to protect the wall in case of new cracks. 


     5. Install a dimple mat and a drainage system


Install a dimple mat and screen

A dimple mat is a sheet of thick plastic (high-density polyethylene)—made with molded dimples. It is used for creating air spaces between the wall and itself. With a dimple mat, the concrete is protected as water flows away from the basement wall.


     6. Use a footing drain


Note that a dimple mat needs to be installed with a drainage system: a footing drain, for example.

A footing drain, which is a perforated 4-inch pipe, can be used to convey the water away.

The footing drain should be installed below the basement floor and the hole should be backfilled with gravel. Backfilling means refilling the excavated hole around the foundation. This strengthens and supports the building’s foundation as well as improving water drainage. Gravel is perfect for backfilling because it is durable and allows for proper drainage.


While waterproofing your basement wall, never use tar to patch the cracks. Tar tends to crack easily.

Also, never use thin plastic-like materials as a waterproof barrier. These will peel off easily.

And lastly, never backfill your drainage system with limestone. Limestone will actually cause poor drainage and clog your system. The best option for backfilling is gravel.


When the walls of your basement get wet, your health and property value is at risk.

And when the rain comes, waterproofing the outer walls of the basement is crucial. 

Moreover, if you want to prevent mildew and mold growth, waterproofing your basement walls is the answer. Note that once mildew and mold begin to grow, they become difficult to remove. These molds are not only dangerous to your health but can also cause structural damage to your home.

Hiring a professional is always the best practice, but if you are on a tight budget, there is no harm in doing it yourself. Just ensure you use quality waterproofing products that can give brilliant water resistance.

  1. I live in a very rainy part of Scandinavia, and I’m looking to buy a house in the country, with a few animals, close to nature. This is very helpful information! It’s nice to get a quick overview of things to consider like this, as I wouldn’t really know where to start on my own.

    I need to bookmark this website for future reference. Thank you Bob!

  2. Hi Bob
    Thanks for sharing this informative article. You described the process very well.

    It definitely sounds like a job for the professionals and I am sure it will be quite costly although more affordable than losing your home to mold or water.

    We were thinking of using foam insulation panels on exterior to help further insulate. Is this a viable option? We are in Canada so the cold is a concern.

    Do we need to do all the steps or pick one? How do I know which one is best?

    Thanks again.

    • Hi Rick, If I had water in my basement, I’d start by going outside and checking the house out when it is raining. This way you can see where the water is pooling. Check the gutters and see if the water is staying around the house. If it is then install down sprout extensions underground and have it dump out about 20′ from the house. Next check the soil around the house. Is the water flowing toward or away from the house. If toward the house then grade the soil so water will flow away from the house. If water is still coming into the basement after checking and eliminating the problems around the house, then make a plan on what you need using the article as a guide for fixing your water problem. Checking outside first will save you money in the long run as the fixes are far less costly. Thanks for reading my post. Take care, Bob

Leave a Reply

Your email address will not be published. Required fields are marked *