How To Seal Basement Walls

  • June 8, 2019
  • / By Dale Keese
Hand on Wall

Basements, as the term itself indicates, are built below grade. For this reason, they tend to more susceptible to water damage. It is very common for the walls of basement structures to retain moisture, form water puddles or even get flooded when the weather is rainy. This humidity, dampness or water logging in the basement of your house can cause some major headaches like peeling paint, the growth of extraneous elements like mold and the rotting of the wooden structure. Moisture can also wreak havoc on the items stored in your basement.

Basement Black and White

When a house is being constructed, the builders are cautious enough to seal and waterproof the basements. Over time, however, there can be cracks that develop in the walls of the basement as the house settles. When the soil outside your basement becomes saturated with water for any reason, the absorbed water can seep through these cracks. Even if there are no cracks in your wall, you may notice dampness in your basement walls as the water transfers from the wet soil to the exterior of the walls and finally to the interior. As the water evaporates, your basement will become more humid and damage the things you store in it.

The best way to avoid such a situation is to seal the walls of your basement so that no moisture can seep through them. There are different ways in which this can be done and while some may need the assistance of a professional contractor, you can also opt for a simple at-home remedy to seal your basement walls.

The key to sealing the walls of your basement is a good quality basement sealer that will keep the contents of your home and its foundation from being damaged by leakages. The first step is identifying the places from which the walls need to be sealed to stop any leaks or damage. Once you determine the issue, you will be better equipped to choose a sealer that can fix the problem.

Step-By-Step Guide

If you are undertaking the project of sealing your basement walls on your own, here is a step-by-step breakdown of the process that will take you through all of it without any difficulty. This is ideal for those of you who are facing such a problem but do not want to enlist the help of a professional or spend extra money.

Step One - Discover the Source of the Problem

In order to seal the walls of your basement, you will first have to find out what the source of any problem that you are facing is. In some cases, it is very easy to locate as you can see water seeping in through cracks. However, the process becomes tough when you can’t see any obvious cracks to gauge the exact place from where the moisture is being let in. In such cases, it is important that you waterproof all the walls on the inside to make sure that there is no moisture at any place.

Basement Lighting

Step Two — Fill in Any Obvious Cracks

Even if you are not sure if you want to seal and waterproof all the walls of your basement, you will have to go through this step. This involves filling in any cracks and possible gaps in the wall and it forms a very important starting step when you are sealing and waterproofing walls. If you end up skipping this step and the cracks are not filled well, the water that you have worked so hard to keep out will find its way back into your basement with great ease, making the entire process counterproductive.

A number of products readily available in the market can be used to fix up the cracks or holes in the walls of your basement. These range from regular cement fixes to epoxy sealers. Each of these come with a set of easy instructions to follow. It is important, however, that you wait for the product to dry completely before you go over the walls with sealers.

Concrete Wall

Step Three – Apply Concrete Sealers

After you have sealed all the individual cracks and gaps that were present in the walls of your basement, you will need to pick the right kind of sealing option to waterproof the walls of your basement. If there is no paint on the wall or if the cement is the outermost layer of your wall, you will have two options in hand – concrete sealers or silicate-based sealers.

The first type of sealers – the concrete variants – give you the benefit of adding another layer of the product onto the surface. These sealers dry in layers and need to be applied to the wall in layers with a sturdy brush. On the other hand, silicate-based sealers are the ones that create a coating on the wall that you are sealing with the help of chemical reactions.

Home Improvements

Step Four – Apply Acrylic Sealers

The other case is where the walls of your basement are painted. In such cases, you cannot use the concrete or silicate-based sealers that were discussed before as these sealers don’t work on surfaces that are painted. Your last resort to waterproof in this case. While acrylic paint works in a manner that is pretty close to regular paint used on walls, this variety goes on in a bigger layer than the regular variant and forms a more distinctive covering.

For example, the amount of acrylic paint that is required to cover one wall could cover four similar walls if it was replaced with ordinary paint. The waterproof paint does not require any special type of brush for application. You can use regular painting supplies to get this paint on your walls. Layering is important so once the first coat of paint has dried, you can add another layer to give you better coverage. 

Hand on Wall

Step Five – Check the Exterior Well

Once you are satisfied that the interior is sealed properly, it’s recommended that you ascertain whether the exterior is secure so that the foundation of your house is not susceptible to water. First, make sure that there is a sloping pattern as you move away from the house. This slope should drop significantly as you move away from the building. There may be the need to build up some mud to the outside to make sure there is a proper slope and ensure that there is no contact with sole plates.

Step Six – Check Things That Are Close to Your Basement

One other way in which water enters the basement is where external sources come into the picture. An example of this a damaged gutter system or the growth of plants in the vicinity. This can be prevented by making sure that the gutters are cleared of any debris so that the water from a faulty system does not move towards the foundation of your house. Also, ensure that the gutters are not located too close to your house and face the other side. 

After ensuring that the gutters aren’t the problem, check if there are any plants too close to the house. It is also possible for plant roots to turn into portals for water reaching the base of your house or building.

Light from Windows

Step Seven – Consider Alternatives

Different situations call for additional steps to be taken, especially when the leaks are more severe. If you cannot turn to waterproofing walls or it hasn’t been effective, you may turn to sump pumps. These are great as they help in removing water when the levels reach a specific point. These pumps are also known for moving the water in a direction that the foundation isn’t harmed.

Another option is a French drain, which uses a bunch of pipes that are laid under the basement and around the house. However, if the moisture problem is still not solved, you should think about investing in a dehumidifier that is specifically designed to keep moisture under check.

Basement Stairs

Some Do’s and Don’ts When You Are Sealing Basement Walls


  • Determine the source of the water.
  • Fill all cracks with hydraulic cement.
  • Use a masonry waterproofing product to the bare interior basement walls.
  • Take preemptive steps to keep water away from your basement.


  • Do not make wall repairs while the water is standing in the basement.
  • Do not forget to address any leaks in the window wells.
  • Avoid applying sealer over walls that are painted.
  • Do not forget about interior drainage solutions.
Light and Shadows on Walls

Finally, remember that moisture can be very harmful for the foundation of your house and you must ensure that you use sealing methods to keep it out. You don’t need to employ the help of a professional. Instead, take it up as a DIY project and save some money!