White Spots in Pavement After Sealcoating

Have you received a complaint about white spots in pavement after you’ve sealcoated the asphalt? Learn what they are and what can be done about them.

Judson Burdon
Posted by Judson Burdon on September 9

Unfortunately, white spots in pavement may happen at any asphalt sealcoating job. It’s unavoidable. It’s also something no worker is at fault for, regardless of what the customer says. However, companies should prepare for finding white spots in the pavement all the same.

When White Spots Appear in Pavement

Once crews apply black asphalt sealcoating, the white spots in the pavement are significantly more apparent. During the final inspection, customers may even point out the white spots. The spots are not created during the sealcoating process, though.

Before the crew begins the asphalt sealcoating process, most parking lots and roads are a gray color. This is from oxidation. With this shade of gray, the white spots are not obvious. However, they're still there.

What Causes White Spots on Pavement

Most soils carry a level of mineral salts, often dissolved in water. These determine the salinity of the ground. Since asphalt is in direct contact with the soil, soils with high salinity have profound effects on pavement and may seep up from the cracks.

The other major potential salt source is limestone. Limestone contains calcium carbonate. Since limestone is inherently crumbly, it travels far. It may be part of the local soil or brought in within a gravel mixture.

White spot-causing salt is present year-round. However, some locations may have more salt than others. For example, salting a parking lot in the winter does leave deposits. These location-specific events may increase the amount of visible white spots.

Sealcoat Edger

What Not to Do

While the white spots may make the job appear incomplete, adding another layer of sealcoat does not solve the problem. Eventually, the white spots will appear in the same location. The company will have spent those resources for no benefit to the customer.

Fixing White Spots in Pavement

The biggest solver of white spots in the pavement is time. As the area is exposed to the elements, the salts causing the issue will wash away. It’s not advisable to force the washing, especially around fresh asphalt sealcoat. Simply reassuring the customer that the white spots in their pavement will go away with time is best.

White Spot Prevention

There is no permanent way to ensure white spots do not appear. However, you can reduce the risks by sealing cracks as they form. There will be fewer spots then for salt to collect on the asphalt surface.

First, clean the area and create a smooth edge inside the crack. From there, do a final cleaning to clear out any debris or dust. Then the asphalt crack can be sealed by adding the flexible sealant. Following this procedure helps the crack sealant adhere to the crack walls and last longer.

Recommend an ongoing schedule of crack repairs to help prevent white spots and white cracks in the long run.


Topics: Asphalt Maintenance, Sealcoating

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