The Portland Timbers have announced an ambitious expansion to their home stadium Providence Park, which will add 4,000 new seats to the east side of the city-owned stadium. Since the team joined Major League Soccer in 2011, the Timbers season-ticket waiting list has swollen to 13,000, and newer, soccer-specific stadiums around the country have pushed the average league attendance above 21,000.

"We feel that if we don't invest in the stadium, the stadium might not be viable in 2035, when the current operating agreement expires," says Timbers president of business Mike Golub.

Construction will take place over two off-seasons. Pending city approval, the Timbers will begin work this coming off-season to have it ready for the 2019 season. The project will be 100 percent privately financed by the team, with investment from an unknown "private partner," per a team fact sheet.

"We pay a ticket tax on tickets sold for every event," Golub says. "So the 4,000 more seats we're bringing to the stadium will generate more ticket tax revenue for the city."

The existing seats along the east side will remain in place, while a four-story, near-vertical wall will be erected above it, with new concourses jutting out and extending over the SW 18th Avenue sidewalk. A sweeping roof will protect the new seats from the rain, which hopefully will have stopped by 2019.

The Timbers say existing season ticket holders will be given first chance to transfer their seats to the new section, based on when their priority numbers (i.e., the date they originally bought their tickets).

Portland's Allied Works Architecture—responsible for big-name projects around the world, including Wieden and Kennedy's Pearl District headquarters, US embassies, art museums, and university buildings—spearheaded the new design, taking inspiration from London's Globe Theater, which has vertical, high seating, and Boca Junior's La Bombonera stadium, which faced very similar urban constraints to expansion.