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Tar Coating

Tar coating is the process of damp proofing the basement from the outside during construction. In cold, damp weather, tar can take up to seven days to dry properly.

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Tar Coating: How Effective is it?

True, concrete foundation walls are durable and mostly maintenance-free. But they’re not water-resistant. Their porous nature means water and water vapor can seep through walls and floors. When there’s a downpour or snowmelt, you’re likely to experience water issues. These can lead to dampness, wood rot, mold growth, and other problems.  

Some homeowners use tar coating to stop dampness. Is this an effective deterrent against moisture? If not, what are your waterproofing options? We will take you through the steps of tar coating the foundation then look at the pros and cons of this damp proofing method.  

What Is Tar Coating?  

Tar coating is a common sealer that’s used for basement damp proofing around the country. Once the foundation is built, the bituminous compound is applied to the exterior walls, and a drainage pipe is set to deter water and moisture that’s threatening to get into your basement.   

Three gallons of tar is enough to cover 100 square feet. Tar takes four to eight hours to dry at 50% relative humidity and approximately 24 hours to set in. In cold and damp weather, tar can take up to seven days to dry. 

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 while time, so once you apply it, you can count on a level of protection for a while. 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.  

Water always wins. When water remains around your home’s foundation for long periods, it is bound to find a way in regardless of new tar or not. Certain joints can not be tarred, and any areas where the tar didn’t adhere well will be first to leak.  

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 can help against some 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 repair 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 Groundworks. 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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