In what was a widely expected move, the Seattle Landmarks Board approved the designation of KeyArena—formerly the Seattle Center Coliseum and Washington State Pavilion—as a city landmark on Wednesday. The structure met all six criteria for being designated.

The move will protect its iconic, Paul Thry-designed roof—which is said to mimic a Northwest Native American rain hat—and the exterior structure. It joins the Space Needle, the Pacific Science Center and the Alweg Monorail as major landmarks and survivors from the 1962 world’s fair that brought them into being.

The decision is key for the renovation plan for the arena the city is working out with Oak View Group to renovate the interior into a world-class music and sports venue worthy of a NBA and NHL franchises. Oak View has made preservation a part of its financial plan. They hope to take advantage of federal tax breaks that can be earned by designated landmarks. Those tax breaks could be worth tens of millions of dollars to the more than half-a-billion dollar renovation plan.

Landmark status also raises the bar on any future proposed reuse or demolition of the structure. The Key can be modified—particularly the interior which has previously been redone numerous times—but the basic exterior form must remain intact. Even if the plans fell through between the city and OVG—say if the proposed SoDo again became a preferred site for a new arena—options for repurposing the Key would have to be explored before demolition could ever be considered.

The city did reject landmark status for some other structures on the Key Arena site, notably the remainder of the heavily altered NASA Pavilion that housed historic space age technology during the fair.

In other city landmarks news, the state Supreme Court made a sweeping decision supporting the legality of the landmarks ordinance, which had been challenged by the University of Washington. The UW claimed it was not subject to the law. The UW sued the city and a local modern architecture preservation group, Docomomo-WeWA, which had nominated a building on the UW campus to protect it from demolition. Other preservation groups joined the suit.

The building was demolished, but in late July the court found that the UW was covered by the ordinance. Preservations and the city hailed the decision, an important win for preservationists.