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Tar Coating

Tar coating has been used for years as a waterproofing solution. But how effective is it, and can it protect your basement on its own?

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A lot of homeowners are caught off guard when their basement becomes extremely humid even though there aren’t any broken pipes or leaky appliances. What they do not realize is that concrete is porous and although concrete walls seem very sturdy and like nothing can pass through them, moisture can easily sneak in. This is often the case with basements that have not been waterproofed. 

When concrete walls are built, one of the materials used to construct them is water. When the concrete begins to cure, the water evaporates, leaving behind tiny pores in the walls. Although you cannot see them, they are there, and they are an open invitation for moisture to come in. During downpours or snowmelt, the water saturates the ground around the foundation and slowly infiltrates the walls. Unfortunately, a moist basement is an ideal environment for mold growth. In addition, it can cause wood rot and a lot of other problems. 

Regardless of whether you use your basement as a storage room or you wish to turn it into a comfortable living space, moisture is not one of the things you want in your home. If you do not keep humidity levels under control, moisture will damage your foundation, compromise the structural integrity of your home and even impact the wellbeing of your loved ones.  

There are several ways you can keep your basement moisture-free. Many homeowners use tar coating to solve this problem, but is it really a good idea? If you want to apply tar coating to your foundation walls, here are several things you should keep in mind. 

tar coating on exterior wall

What Is Tar Coating? 

Tar coating has been around for a long time to keep basements free from moisture. This method is used across the country and when builders are constructing the foundation, they often use this compound on the exterior walls.  They use approximately three gallons of tar on every 100 square feet of exterior walls. This coating can dry completely in just one day under conditions of relative humidity. However, if the temperatures are low, this process can take up to a week. 

How to Apply Tar Coating to the Foundation 

To complete this project, the builders or other contractors will clean the foundation walls and remove any dirt. Next, they will fix the cracks in the foundation, if there are any. In the end, they will apply tar coating with even strokes. When applying the coating, contractors will make sure that it extends one foot above ground level. After the coating has dried, they will apply a latex primer. 

What Affects Tar Coating? 

Is tar coating a good solution? Its effectiveness depends on several factors.  

It is important that contractors thoroughly clean the wall because if any dirt is left behind, it will lower tar’s efficiency. Also, things like temperature and humidity can impact its effectiveness. When a tar coating is applied, it is important to strictly follow the manufacturer’s guidelines and instructions. The presence of moisture on the exterior foundation wall also plays an important role.  

If you are wondering whether tar coating is a suitable solution for your basement, here are the pros and cons of using this method. 


Tar coating is seamless and therefore has the power to effectively stop dampness. It can last a long time, so once you apply it, you can relax knowing that it will keep your basement protected for years to come. Tar coating also has high tensile strength and is a great line of defense against hail, fire, and wind. 


One of the reasons why you should let professionals apply tar coating is because this component releases toxic fumes. These harmful fumes can lead to skin and lung problems. Therefore, do not try to do it yourself or you could get seriously hurt. 

As we mentioned, if your foundation walls have any cracks, it is necessary to seal them properly. Placing tar over them will not solve the problem. Instead, contact your local foundation repair experts and have them seal any large openings in your basement walls. 

Waterproofing the Foundation 

Contractors have been using tar coatings for years and it is an effective way to protect your basement against moisture. However, if you want to avoid any kind of water damage, tar coating on its own will not get the job done. Instead, you should invest in other waterproofing measures.  

If there are any cracks along your foundation, you need to seal them as soon as possible. Also, install and maintain your downspouts regularly so they can direct water away from your home. In addition, consider installing an interior drainage system that will run along the entire perimeter of the basement, collect excess water, and direct it to a sump pump

It is also important that your yard is not poorly graded. In case the soil has a negative grade, you might experience problems with your foundation. If you are wondering whether your yard is graded properly, just go outside during the next rainstorm and see whether the water runoff is moving toward or away from your home. If it is pooling around your home’s perimeter, you will need to regrade your yard. Installing gutters on the roof is also a great way to prevent pooling next to your home. 

Some contractors recommend combining tar coating with exterior drainpipes. However, this type of drainage requires a lot of excavation and will ruin your landscaping. 

If you wish to learn more about waterproofing solutions, contact professionals at AFS. Schedule a free inspection and one of our experts will inspect your foundation, determine if there are any problems that need to be fixed, and recommend suitable waterproofing solutions that will keep your basement dry for good. 

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