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Tar Coating

Applying tar coating can be an affordable way to protect your foundation walls against moisture. But does it work as well as they say?

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Most homeowners believe that just because concrete foundation walls are durable and do not require a lot of maintenance, they will protect their home against moisture. What most of them do not realize is that concrete is porous. The pores in the concrete are so tiny, that you cannot see them. However, they are big enough to let moisture in.  

When the concrete for the foundation is poured, half of the water from the concrete mixture evaporates, leaving behind a trail of capillary pores. These pores make a convenient passageway for water molecules. While at first only water vapor will be able to enter your basement, when the pores get wider, the water will break through. During downpours or due to melting snow, you can easily experience unpleasant water issues. As you might know, water damage is a highway to wood rot, mold growth, and other problems. 

Whether your basement is used as storage or you have transformed it into a living area, you surely do not want any moisture down there. In addition, moisture can impact the health of your foundation, and therefore the health of your home and your family. So how can you prevent these moisture issues? Some homeowners use tar coating to solve this problem. But does it get the job done? How effective is tar against moisture and what are the other waterproofing measures you should consider? Read on to learn more about coating and its characteristics. 

Tar coating

What Is a Tar Coating? 

Using tar coating to keep the basement damp-free is not a novelty. In fact, this method is used all around the country. When the contractors are building the foundation, they apply this compound to the exterior walls, and afterward, a drainage system is installed to direct water and moisture that’s threatening to get into your basement away from it. 

So, how much tar should be used to cover the walls? When applying it, contractors use three gallons of tar to cover 100 square feet. It takes a day for tar to dry under conditions of relative humidity. If it is cold outside or damp, it can take up to a week for a tar coating to completely dry.  

How to Apply Tar Coating to the Foundation 

If you hire construction experts to apply a tar coating to your below-grade foundation in North Carolina, here is what you can expect. 

  • Contractors will need to clean the whole exterior foundation wall to remove any dirt and loose debris. 
  • If there are any cracks, these will need to be fixed before moving on to the next step. 
  • Contractors will apply the tar coating using even strokes. After leaving it to dry a day or two, depending on the weather conditions, they will apply latex primer. 

It is important that the coating extends one foot above the ground level. 

What Affects Tar Coating? 

The effectiveness of this coating depends on several factors. First, the surface of the wall needs to be completely clean, otherwise, the tar coating won’t keep the moisture out. It is also important to thoroughly follow the manufacturer’s guidelines and instructions. Temperature and humidity can also impact the effectiveness of the coating, as well as the presence of moisture on the exterior foundation wall. You should take into consideration the chemistry of the fiber reinforcement. 


Since this type of coating is seamless, it can effectively stop dampness. It is durable and has high tensile strength, and once you apply it, you can be at ease knowing that foundation walls will stay protected for several years. Tar coating is also handy against hail, fire, and wind. 


It is not recommended to apply it by yourself, since during the application process, the tar can release toxic and harmful fumes. Therefore, leave it to the professionals. Harmful tar fumes can lead to skin and lung problems, so avoid DIY projects with it. 

As mentioned, before applying tar coating it is important to fix any foundation cracks. Simply applying a coat of tar over them won’t solve the problem. Therefore, contact contractors to seal cracks and other large openings before applying any waterproofing measures. 

Waterproofing the Foundation 

Using hot liquid asphalt to protect foundation walls from moisture has been a popular practice for years. However, you need to keep in mind that this method won’t stop water from entering your basement on its own. You need to implement other waterproofing measures if you wish to protect your basement. If you have any cracks along the foundation you need to seal them. In addition, to stop water from pooling near your home’s perimeter, you can call the contractors in your area to install a French drain, as well as downspout extensions that will direct water away from your home to the public drains or streets. 

Another thing you could do is to make sure that your yard is properly graded. If you have noticed that during rainy days rainwater goes toward your home, you will need to regrade your yard. Installing gutters on the roof can also prevent roof water from pooling next to your home. 

Many contractors recommend combining tar coating with exterior drain pipes. With these protective measures, water won’t be able to build up around the home. By directing water away from the foundation’s perimeter, you will prevent it from infiltrating the basement walls. 

Instead of relying on the exterior tar coating to keep water out of your basement, why pair it with or opt for a more permanent interior solution? Basement waterproofing measures including an interior drainage system, a sump pump, and other solutions will make sure your basement stays free of water for years to come. Would you like to know more about all the ways you can keep your foundation protected from water damage? If so, do not hesitate to contact the expert team at Tar Heel Basement Systems to schedule a free inspection. Our professionals will examine the state of your foundation and recommend proven solutions that will keep water out of your basement for good.

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