White spots that appear in pavement and what they are - by Craig Swain

Have you had your parking lot sealcoated and found white spots coming through the sealer? You are not alone, unfortunately it’s not the contractors fault that did the work. These unsightly spots are becoming very common. In most cases these spots were there well before the sealer was applied, they just did not stand out as much on oxidized (gray) pavement. Once a new black sealcoating application is put down, the spots become more apparent to our eyes.

These white spots are caused by elements in our environment. These elements are most commonly mineral salts or calcium carbonite (part of lime stone). These elements are in the soil, water and gravel under and along the pavement. Salt is actually present year round and usually water is how these elements got into the pavement to begin with. When there are cracks in the pavement sometimes these elements get pumped up from below the pavement through the cracks that have not been filled or filled properly.

Time is usually the best option to have rain water run off these spots. If another sealcoating application is applied these spots will just get locked in between the layers of sealcoating material, and will eventually they will come through to the surface again. 

In the end, these white spots are very common and there is little to nothing anyone can do about them other than let mother nature help wash them away. There are photos included of what these white spots look like in case you have some in your asphalt.

Craig Swain is the president of New England Sealcoating Co., Inc., Hingham, Mass.