The state Department of Transportation plans to start a two-mile overlay project early next month on all southbound lanes of I-405, from Northup Way to Southeast Eighth Street.

The $5.06 million project includes grinding more than an inch of surface and filling it in with new pavement. That stretch of interstate was last paved over 19 years ago, said Kris Olsen for WSDOT.

“It is due for new surface there because it’s filled with cracks and new potholes,” she said, adding the project improvements should hold for up to 15 years.

WSDOT has set June 8 as its tentative date to begin the overlay project, which Olsen said will be restricted to nighttime work and closures, beginning as early as 8 p.m. Sunday to Friday and up to 5 a.m. Saturday work could begin as early as 7 p.m. with a Sunday morning reopening by 7 a.m., she said.

The project also includes repaving several ramps along the two-mile construction site, including southbound I-405 to westbound and eastbound State Route 520, and eastbound SR-520 to southbound I-405. There may also be times when the northbound 405 HOV lane is closed for replacing and repairing guardrails, Olsen said.

According to WSDOT, around 175,000 vehicles travel this section of I-405 daily.