Skip to content
Climate Pledge Arena

Real estate developers

Award-winning engineering work builds Seattle’s new Climate Pledge Arena while preserving historic architecture

22,000 tons

Weight of historic landmark roof, which required temporary support, demolition of existing supports, and new permanent support

800,000 square feet

Size of the new arena — more than double its previous square footage and 15 feet deeper


  • Haley & Aldrich helped double the size of Seattle’s outdated, too-small KeyArena, solving dozens of unexpected complications to deliver a new home — the first certified zero-carbon arena in the world — for the NHL Kraken and the WNBA Storm.
  • The arena’s historic concrete roof had to be protected during demolition and construction. The project team trusted Haley & Aldrich’s engineering expertise and creative thinking to meet this challenge.
  • The brittle roof could tolerate only a quarter inch of movement between its supports as its weight was transferred first to temporary supports and then to a new permanent support system.
  • Our engineers designed and installed an extensive automated monitoring system to track the structure’s integrity during the weight-transfer process and remaining construction, which reported data for more than 1,100 targets on and around the concrete roof and shoring system every four hours.
  • The renamed Climate Pledge Arena opened on time, despite the onset of the COVID-19 pandemic in 2020 and millions of dollars of enhancements added to the project during construction. Our work kept the project on schedule while preserving an existing city landmark and creating a new one.

For more information, contact:

David Winter

Senior Principal Consultant