Construction Project: North Base “green roof” liner replacement

Metro will start construction in May 2012, and the project will be completed by December 2012, with the park reopening in spring 2013 to allow for establishment of the new grass playfield.

Metro’s underground bus parking garage is over 20 years old, and the waterproofing membrane on the roof has passed its useful life and is leaking into and causing deterioration of the structure.

The waterproofing application must be done in the summer when there are extended dry periods to allow the concrete roof to become dry prior to application and to allow proper curing of the membrane.

Construction noise will be primarily from truck traffic in the neighborhood when soil and other construction materials are transported to and from the site. No noisy construction will occur before 7 a.m. An odor similar to that of asphalt paving will be produced during a couple of weeks in the summer when the waterproofing is installed. While the odor may by unpleasant, it is not harmful.

The park on Metro property will be reopened in spring 2013, following establishment of the new grass. The portion of Keogh Park used for soil stockpiling will be reopened in fall once landscaping is complete on the green roof area.

Yes, the decorative tiles will be removed, stored, and replaced during the project. Any tiles that are deteriorated will be replaced.

Yes, trees bordering the site will be protected in accordance with a plan developed by a professional arborist certified by the City of Shoreline.

During certain phases of the project, up to 50 Metro employee cars may be temporarily displaced from the onsite parking lot to on-street parking in the neighborhoods next to the base. This on-street parking would occur throughout the day, including early morning and late night periods when peak transit operations occur. To reduce parking on local streets, Metro is arranging for additional parking at King County facilities.

The construction contractor will prepare and carry out a traffic control plan and a sediment control plan throughout the project. Metro will inspect the contractor’s implementation of these plans every day to ensure that they are effective.

Work hours will be from 6 a.m. to 6 p.m. weekdays, and no noisy construction will start before 7 a.m.

No, street closures will not be required for this project.

No. The parking lot will be used by Metro employees this summer during the employee parking lot repair work, and then will be closed for repairs through the fall 2012.

Extensive stormwater erosion control and pollution prevention measures will be used to collect and treat all runoff during construction. Water quality will be monitored to ensure that there are no unacceptable impacts to the receiving water. In addition, we will follow air pollution control measures when the waterproofing membrane is applied to reduce odors and prevent any unacceptable impacts to neighbors during the short application period.

King County sustainability measures are being fully implemented during this project. These measures including reusing the 80,000 square feet of sod for environmental restoration work at King County’s Cedar Hills Landfill (in cooperation with King County Solid Waste) and onsite reuse of 1,500 cubic yards of topsoil and 500 cubic yards of drain rock. In addition, 1,200 tons of concrete parking-lot pavement will be recycled offsite.

Please call our message line, 206-296-4410.