Microsurfacing Street Resurfacing Trial Project
What is Microsurfacing?
Microsurfacing is a protective seal coat which extends the life of non-arterial streets. It is a thin, tough layer of asphalt emulsion blended with finely crushed stone.
This is a cost-effective method to renew the road surface and seal minor cracks and other irregularities. This preventative maintenance process protects the pavement from moisture penetration and oxidation. Similar to painting a house, microsurfacing creates a protective layer which prevents the need for more expensive repairs in the future.
2013 Microsurfacing Pilot Project Compared to Chip Sealing
Many transportation agencies use microsurfacing as an alternative to chip sealing. (About 1/4 of Seattle’s non-arterial streets are chip seal streets.)
In 2013 SDOT is conducting a microsurfacing trial project on selected streets which were traditionally chip sealed. SDOT will monitor the streets in this pilot project to help determine if microsurfacing will be used on other streets in the future.
Chip sealing has the advantage that you can drive on the street immediately, but with microsurfacing you must wait about two hours for the surface to cure before driving or walking on it.
Why are some Seattle streets chip seal streets?
In the 1960’s, most of the streets in Seattle which we now call “chip seal streets” had a dirt or gravel surface. The City converted them to chip seal to provide a smooth driving surface, reduce dust and improve air quality. Now these streets are maintained through chip sealing or other alternatives such as the 2013 microsurfacing pilot project.
Our street looks fine. Why resurface it?
Chip sealed streets need periodic resealing to protect them from the deteriorating effects of water (rain) and sun. If left untreated, the surface becomes brittle and may crack and ravel. Periodic resealing through chip sealing or microsurfacing prevents more extensive and costly repairs. Regular preventive maintenance is the most cost effective way to maintain streets.
All the blocks in the 2013 microsurfacing project were selected based on the age of the current pavement and an on-site inspection by SDOT staff.
The 2013 pilot project is in the Wedgewood neighborhood, bounded roughly by:
Most of the streets in the northern portion of the project area and selected streets in the southern portion will be microsurfaced.
Note: some streets may be removed from the 2013 project based on unforeseen factors.
For a map of which blocks will receive microsurfacing and the schedule with the specific day the work will occur each block, click here or on the map above.
*Schedule is subject to change due to weather or unforeseen factors
If the work on your block is postponed due to rain, you will be informed as follows:
Preparing the street: fixing potholes, cracks, etc.
Streets are prepared for microsurfacing and chip sealing in the same way. It is essential that damage to the road, such as potholes and cracks, is repaired prior to the microsurfacing process. SDOT crews will begin to patch deteriorated areas of the selected roads well in advance of the microsurfacing operation.
In addition, low hanging branches and overgrowth may need to be trimmed to allow for the microsurfacing equipment to navigate the roads.
On the day of microsurfacing, crews will sweep the street before applying the microsurfacing material.
The Microsurfacing Process
Microsurfacing is a process similar to a slurry seal. A mixture of asphalt emulsion and aggregate (crushed stone, gravel and sand) is applied to the road. However, unlike a slurry seal, microsurfacing uses emulsion that is modified with polymers and other ingredients so it cures quickly and provides better durability in the long run.
As shown in this short video, as the microsurfacing equipment moves along the street, the mixture is fed into a spreader box. The material is spread across the full width of a traffic lane and then smoothed by a squeegee. The equipment also feathers the edges for a smooth transition. All this happens in one step.
After about two hours the microsurfacing seal coat cures (hardens), and the street can be reopened and used normally. However, please be prepared for parking restrictions and road closures for the entire day the work is scheduled. See details below under “How Residents are Affected by the Project.”
Sometime during 7am – 5pm on the scheduled date, the full width of the block will be fully closed for two to three hours. Two to three hours is the time typically needed to complete one block. This includes set up, sweeping, applying the microsurfacing seal coat, curing (hardening), and reopening of the street.
These two to three hours can occur at any time between 7am – 5pm, but we cannot predict when these two hours will occur for a particular block.
Limited Access to the Road at Unpredictable Times
“Road closed” signs will be posted on the block for up to a full workday (7am – 5pm). However, before and after the two to three hours of seal coat application and curing, you may walk or drive on the street with assistance from crews. Crews will work to minimize delays and will provide assistance navigating around the work zone. Traffic flaggers may be present during the work.
Sidewalks will remain open at all times.
Wait Two Hours to Use the Street
About two hours after the project is completed, crews will remove the “no parking” signs and you may drive, walk, bike or bring pets on the street.
Do Not Park on a Block When Work is Scheduled
No Parking” signs will be installed at least 72 hours before the start of work. On the day a block is scheduled for work, please do not park on the street. The project is phased so that you only have to go to the next intersection to find a street which is not scheduled for work on the same day. (See map & schedule.)
No Driveway Access
On the day your block is microsurfaced, there will be no access out of or into driveways during the two to three hours of seal coat application and curing. Because we do not know exactly when those two to three hours will occur, if you will need your car during that day, we recommend parking on a block that is not scheduled for microsurfacing on that day.
Park at Least Two Feet from the Street Edge
On the day of microsurfacing, if you park near the street (such as in your driveway), park at least 2 feet from the edge of the street to prevent potential vehicle damage from overspray of the microsurfacing material.
Garbage, Yard Waste and Recycling Collection on Wednesday 7am – 8am
During the microsurfacing project, garbage, yard waste and recycling will still be picked up on Wednesday. However, pick up will occur between 7am and 8am, which may be earlier in the day than usual for some blocks. On Wednesday, please leave your materials at the curb by 7am as usual, per the City’s rules.
Some blocks NOT receiving microsurfacing WILL be affected
The road closures will affect block adjacent blocks in different ways.
On the day of the work, adjacent blocks may have more cars parked on the street and residents may need to navigate around the closed streets.
Access on a small number of adjacent blocks will be impacted at a similar level to access on the blocks receiving microsurfacing. For example, the only way to get to the 8000 block of 41st Ave NE is from NE 80th St. Therefore, on July 31st, when this section of NE 80th St is scheduled to be closed for up to a full workday, residents of this block of 41st Ave NE who plan to use their cars should park on another block.
National “Night Out” Block Parties Aug. 6
We will strive to avoid conflicts with “Night Out” block parties on Aug. 6. Please note that if rain delays are limited or do not occur at all, the project will be fully completed before Aug. 6.
It Could be a Rough Road for a Bit
Right after microsurfacing, the road may have a slightly coarse driving surface. As cars drive over the road, however, the surface will become smoother, but still have enough traction to provide skid resistance.
SDOT appreciates the cooperation and efforts of Wedgwood residents and others who are affected during this street maintenance project.
We welcome your questions and comments.
For Street Maintenance 24-hour emergencies, please call: 206-386-1218.