Chip Seal Program

Chip sealing is one of the most cost effective ways to extend the service life of a road by seven to ten years. Treating a road with chip seal is like painting or reroofing a home before serious deterioration has occurred. Chip sealing will effectively “waterproof” the road and prevent or minimize the deleterious effects caused by rain and sun.


The Chip Seal Process

Road Preparation:
  1. If needed, county Road Maintenance crews will repair potholes, seal cracks, and/or pre-level the road surface by applying a layer of hot asphalt.
  2. Within one month (typically) following the pre-level work, crews place crushed rock along the shoulders and stripe or place temporary markers where necessary.
  3. Brush cutting, road sweeping, and other preparation work takes place prior to the chip seal placement.
Chip Sealing:
  1. A layer of asphalt oil is applied to the road when weather is sufficiently warm and dry.
  2. This is immediately followed by a layer of crushed rock, creating a chip seal.
  3. The chips are pressed into place by a roller and the road is immediately usable however, the compaction and adherence of chips to the asphalt binder improves with time and routine. SLOW traffic is recommended.
  4. Crews will return within a week to sweep up loose gravel. If necessary, the road maintenance striping crew will replace pavement markings.
Please Be Aware
A regulatory speed limit of 20 miles per hour will be in effect during the week following the chip seal placement.

Adherence to this temporary speed limit will minimize the likelihood of loose, flying chips causing damage to a vehicle’s body or windshield. Faster speeds and turning movements may also compromise the resulting quality and life expectancy of the new roadway surface.

Snohomish County sheriff’s deputies may patrol the chip seal projects to enforce the 20 mile per hour regulatory speed limit. Remember, fines double in work zones. Slow down, and “give ‘em a break."