Pavement Preservation

Pavement Preservation

Staff Contact:
Tobin Bennett-Gold
(425) 398-8900

Once again, the City of Kenmore will use slurry seal to make our residential roads last longer.  Other cities in our area have been using this method for years and have had great results. Over the last several months, we have worked closely with other cities to learn about their programs, evaluate if it is right for us, and coordinate bidding advertisements.

What is Slurry Sealing and why do it?

  • Sealing the roads is a pavement preservation treatment used to extend the road’s life before costly structural repair or replacement projects are needed. Preserving pavement while it is still in good quality significantly reduces the lifecycle cost of our roads.  Sealing of the roadway begins with sealing all cracks in the roadway which are ¼” wide or wider.  Once the cracks are sealed and enough time has passed for the sealant to cure, a slurry seal is spread along the roadway.
  • Slurry seal is a water/oil/aggregate mixture that is in liquid slurry form. Unlike the asphalt overlay many people are familiar with, which removes and replaces the existing surface with several inches of new asphaltic concrete, slurry seal is a thin coating of asphalt and aggregate spread over the existing road surface. Slurry seal is applied to help preserve and protect the underlying pavement structure and provide a new driving surface.

How Are Roads Selected?

  • Slurry seal is most effective on roads that are starting to show their age, but do not have a lot of cracking. Slurry sealing keeps good roads good and allows the road to have a much longer service life before costly structural repair or replacement projects are needed.
  • Your road may not have a ton of potholes and you may not see much cracking.  But, a little maintenance and slurry sealing now could prevent the need for costly repairs later.
  • Conversely, if your road has a lot of cracking, it may not be a good candidate for slurry sealing and may need a more substantial treatment such as asphalt overlay or full replacement.

Roads highlighted in blue on the map below are scheduled for slurry sealing in August 2019.


How Does the Work Get Done?

  • Trucks hold the fine crushed rock, water, oil, and other additives, which are mixed in the on-board mixer. The slurry mixture flows out of the rear of the truck and workers with squeegees follow behind and assist in spreading the mixture, correcting areas not properly covered, and keeping the mixture off of concrete surfaces such as gutters. 
  • Once placed, the seal needs at least 4 hours to set before the road is open for traffic. After the seal is applied, any striping needed is reinstalled on the roads, and the streets are swept for loose aggregate (immediately and again at one week, three weeks and three months).

How Will This Impact Me?

  • Work is expected to start in August 2019 and last approximately 20 days across the city, but work on any individual road should take only a day or two from start to finish.
  • Crews are permitted to work from 7am to 1pm, so that the slurry seal will be ready to drive on by 5pm each day.
  • Crews will be able to complete about 1 mile of road per day
  • “No Parking” signs will be out 24-hours in advance
  • Residents will not be able to park on the road or use the road from 7am to 5pm.
  • The work should not be very loud and there shouldn’t be strong fumes or smells.
  • You may see or feel little bits of aggregate, but they should not damage your vehicle.
  • Your road may appear and feel a little bumpy and rough at first, but over time it will start to smooth out. and return to normal roughness over the span of several months. 
  • You will still be able to easily ride your bike, rollerblade, or travel with strollers across the new surface…but, in the beginning, it may be a tiny bit more “vibrating”.


Last updated: Fri, 07/12/2019 - 3:29pm