King County Road Services - Asphalt overlay

What is an asphalt overlay?

An asphalt overlay is a road-resurfacing method where a lift of asphalt is placed on top of the existing roadway surface. Asphalt overlays are designed to extend the life of a road's driving surface, keep roads in good condition by preventing potholes and preserving the underlying road bed structure. The asphalt overlay also helps smooth surface irregularities and prevents further deterioration of the road. Here's an example of what an overlaid road looks like.

Asphalt overlay benefits

• Prolongs the service life of the road
• Adds structural capacity to the roadway
• Improves the smoothness of the ride
• Reduces maintenance costs

The overlay process

There are several steps in an asphalt overlay - follow them in the slideshow below. Please note that asphalt overlays are only applied during optimal weather conditions.

Why overlay the roads?

The Road Services Division provides safe travel by maintaining more than 1,750 centerline miles of roadways and over 180 bridges in King County. We are committed to preventative maintenance and preservation of roadways in unincorporated King County. Due to the effects of weather, axle loads, average daily traffic and utility work, asphalt deteriorates over time. An asphalt overlay helps restore and preserve the roadway by maximizing the road’s service life through least cost life cycle methodology.

How does overlay paving affect motorists?

We appreciate your patience while the overlay paving is underway. Crews will make every attempt to work efficiently and effectively. On the higher volume arterial roadways, the overlay contractor will place variable message boards to give motorists advanced notice of possible paving delays.

Contact information

If you have questions or concerns about asphalt overlays, please contact:

Dan Stage, Senior Engineer
Engineering Services Section
King County Road Services Division
206-296-8088

Information from the Road Services Division's website is available to people with disabilities in alternate formats upon request by calling 206-263-6482 or 711 for the TTY relay service.

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