Slurry seal program

Slurry Seal

View the list of roads receiving slurry seal treatment in FY 2020-21.

What is slurry seal?

Slurry Seal mascotSlurry seal treatments fill in cracks and voids in the roadway to prevent water from getting under the surface and to improve skid resistance. This cost-effective, maintenance treatment extends the life of the road surface. The mixture consists of asphalt emulsion, mineral agreggates, water and additives.

What do residents need to know?

Slurry seal is applied as a liquid and requires several hours to solidify. In its liquid form, slurry material is messy, sticky and very hard to clean up.

  • Do not park, drive, walk or bike on the roadway while the slurry is curing.
  • Keep children and pets off the road.
  • Keep water off the street the night before scheduled work.

The first few days after the treatment is applied, the color of the street may appear to be turning darker. This is normal. Vehicles driving over the slurry seal help roll and smooth the surface. During this process, some rocks may loosen and minor, cosmetic defects may appear.

A few weeks after the treatment is applied, crews will perform an inspection, sweep loose gravel, make necessary surface repairs and replace any pavement markings.

What can residents expect?

  • 60 days out: Residents will receive a postcard about the process. Property owners will be asked to trim vegetation encroaching the roadway.
  • About three weeks out: Minor patching, street cleaning, crack sealing and other work will be done.
  • Two weeks out: Residents will receive a second postcard explaining what will happen the day of slurry seal.
  • Two days out: "No parking" signs will be installed.
  • At least 24 hours out: Residents will receive a paper notice from the contracter asking vehicles to be moved off the street by 7 a.m. Those not moved will be towed to a nearyby street.

Service providers, including garbage haulers, will also be notified.

Why is the treatment important?

Preventive road maintenance saves tax dollars. It is less expensive to maintain a road surface than to rebuild it.

The average life of an asphalt road surface is 20 to 30 years. However, many roads start to show signs of distress and deterioration much earlier. Road deterioration can be caused by many factors, including sunlight (which causes drying and cracking) and rain (which can seep into the road causing potholes). Slurry sealing a road every seven to 10 years means repaving is only necessary every 20 to 30 years.

Who pays for the work?

Property owners in the voter-approved Urban Road Maintenance District (URMD) pay $0.25 per $1,000 assessed value on their property taxes for maintenance of local streets.

Who does the work?

A private, professional paving contractor is selected through a competitive bidding process to do the slurry seal work. The contractor must comply with both Oregon specifications and Washington County contract requirements. A Washington County inspector is onsite, ensuring work is performed in compliance with the contract.

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Learn more

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