SF Gate

By Julie Balise on April 6, 2015 1:17 PM

Facebook’s new building is taking the open concept office to a new level.

Called MPK 20, the 430,000-plus square foot building is made of one large, open room. The goal was to “create the perfect engineering space for our teams to work together,” according to CEO Mark Zuckerberg.

“To do this, we designed the largest open floor plan in the world — a single room that fits thousands of people,” Zuckerberg wrote in a Facebook post last week. “There are lots of small spaces where people can work together, and it’s easy for people to move around and collaborate with anyone here.”

MPK 20 has a 9-acre green roof with a half-mile walking loop and more than 400 trees, according to sources familiar with the building. The trees and plants are native to California, making them a possible home for local and native birds. The roof also provides insulation, which may cut heating and cooling costs for the company. The parking lot is underneath the building.

Gehry Partners designed MPK 20, which will be able to hold about 2,800 employees. In a statement, architect Frank Gehry said Zuckerberg wanted a space that was “unassuming, matter-of-fact and cost effective.”

“It is not a grand design statement and it has a toughness and a rawness that reminds me of the work I was doing in the early part of my career,” Gehry said in the statement. “I am very proud of the collaboration and I hope that it facilitates innovation and invention of the highest level.”

Other partners involved with the building include landscape architect CMG Landscape Architecture; contractor Level 10 construction; structural engineers Forell/Elsesser Engineers; civil engineers BKF Engineers; project and cost management from Cumming; mechanical, electrical, plumbing and technology from PAE Engineers; and environmental and geotechnical from Cornerstone. MPK 20 is LEED Gold Certified by the U.S. Green Building Council.

Facebook employees are still moving in to the building.

The company invited 10 Bay Area Instagram users to visit MPK 20 on March 29. They snapped shots of the building, and it’s park, and posted them to Facebook-owned Instagram using #MPK20FirstLook.