A sealcoat is a necessary task for maintaining asphalt paving. How often it is applied depends on your paving's age and your local climate, but generally, every two to three years is common. 

1. Waterproofing

Although a hard paving surface, there are pores in asphalt that allow water to seep in. This slow absorption of water can break down the paving over time, leading to crumbling and pothole formation. A sealcoat creates a waterproof barrier over the top of the paving, severely limiting the amount of moisture that can be absorbed into the paving. The result is fewer chances for water damage and longer paving life.

2. Chemical Damage

A multitude of chemicals can weaken and destroy asphalt over time. Many of them are unavoidable, as they are simply a byproduct of driving on the pavement. These include gas, oil, salts, air pollutants, and chemicals in fertilizers and ice melt products. Sealcoating provides resilient surface protection so that these chemicals don't soak into the asphalt. Any damages affect only the seal-coated surface, which should be reapplied every couple of years.

3. Erosion Prevention

Weathering from constant sun exposure combined with rain and other weather events slowly erodes the surface of an asphalt parking lot. You may recognize it as graveling, a process in which the surface aggregate breaks free of the asphalt bond and becomes loose gravel on the surface of the paving. Sealcoat applications protect against erosion so that graveling never becomes an issue. In fact, sealcoat products tend to be fairly resistant to UV damage, especially when reapplied periodically.

4. Crack Repair

Small cracks can be way too tiny for normal crack repair techniques, but if ignored they will eventually widen and develop into large cracks or even potholes. Although larger cracks and holes must be patched before sealcoating, small cracks don't need any pre-treating. A painted-on sealcoat layer seeps into the small cracks and divots, filling them in and leveling out the paving. 

5. Appearance Improvement

Over time, asphalt color fades and there may be uneven areas due to staining or damaged patches. Since a sealcoat is a polymer sealer mixed with asphalt tar, its color is dark and even. When it's applied over the surface of a faded lot, it renews the color and evens out most variations in asphalt color. The result is an almost new-looking parking lot. 

Contact an asphalt sealcoating service if it is time to have your pavement's surface renewed.