Blocks of concrete will make way for waves of glass at the former Facebook headquarters at Stanford Research Park under an ambitious and controversial redevelopment proposal that Palo Alto officials approved early Tuesday morning.

The City Council voted 7-1, with Tom DuBois abstaining, to approve a plan by Sand Hill Property Company to demolish four existing buildings, at 1050 Page Mill Road, which were built about half a century ago, and construct four glassy two-story structures at the periphery of the 13 1/2-acre site.

Originally used by Beckman Coulter Inc. for research and manufacturing of biomedical instruments, the site more recently served as the home of Facebook, which occupied the site between 2009 to 2011.

Today, the tenant is Machine Zone, a software company that sprung into existence in downtown Palo Alto before outgrowing its headquarters and moving to the Research Park. Best known for its conquest title, Game of War, Machine Zone would also occupy the new buildings, once they're built.

The council's vote, which followed more than three hours of deliberation, came despite some major reservations and complex questions. The council generally agreed that the new buildings, made of glass, topped by solar panels and outlined by a wavy aluminum fin, would be a huge improvement over the existing structures. Even Councilwoman Karen Holman, the only member who voted against the project, called the proposal "very beautiful."

They were far less enthusiastic about the project's potential traffic impacts and the site's dodgy zoning history. In 1999, the large parcel was split into two leaseholds and a new building was proposed on the smaller leasehold. But the splitting of the site also left the larger leasehold with more building density than the city's zoning laws would normally allow. Because the city was not notified about the lease split, it was unable to stop the zoning violation, an episode that planning staff characterized as an "oversight."

On Monday night, several residents pointed at this zoning indiscretion and urged the council to make amends by reducing the floor area of the newly proposed development by 31,000 square feet.

Doria Summa, who lives in College Terrace, argued that the city's planning staff should've required the developer, Sand Hill Property Company, to make the cut before the project went through the entire approval process.

"The idea that anyone can move a lease willy-nilly whenever they want to just to achieve a greater FAR (floor-area ratio) on one site is a lawless and chaotic idea that we never have proceeded with before in the Research Park and I don't see what advantage it would have for anybody to proceed with in the future," Summa said.

The council, however, didn't see it that way. The city's existing agreement with Stanford University, which owns Stanford Research Park, allows about 11.2 million square feet of development at the Research Park, around 1 million short of the current development level.

Much like planning staff and the Planning and Transportation Commission, the council supported Sand Hill's proposal with no significant modifications and no requests for reductions. Most members didn't see any issues with allowing Sand Hill to demolish 265,865 square feet of floor area and replacing it with an equal amount of development.

Allison Koo, project manager with Sand Hill, stressed that the project would not require any variances and is following the code "to a 'T.'" The team is not asking for a single additional square foot, Koo said. The four buildings would be built at the site's periphery, thus enabling a spacious courtyard.

"We believe this presents a smaller project than exists today," she said. "We have an architecturally stunning design that we're really proud of."

The council agreed that the new buildings would be a substantial improvement over the ones that stand there today. Members also requested as part of its approval that the new development accommodate a potential bike path that could be built in the future near the rear of the property, provided the city and Stanford can reach agreements with other tenants.

The council also specified that the landscaping at the campus should include indigenous trees and that the occupant adopt an aggressive "transportation demand management" plan for reducing solo drivers and encouraging alternative modes of transportation.

Traffic, in fact, was the biggest concern for the council. Councilman Greg Schmid questioned the data in Sand Hill's commissioned traffic study and suggested that the methodology used to calculate the new traffic levels is faulty. He noted that the methodology may work in some cities, but could prove problematic in Palo Alto, which has one of the highest jobs-housing imbalances in the nation.

Schmid noted that Sand Hill's own consultant had projected that six intersections will have the lowest level of service: F. Yet the environmental analysis for this project concluded that it would have no significant impacts on the famously clogged up area.

"If we're at the center and we have F intersections, how can we keep saying there's no significant impact?" Schmid asked.

Schmid joined Holman and Councilman Eric Filseth in voting against the certification of the project's Environmental Impact Report (EIR). Holman expressed strong reservations about the zoning oversight and wondered how the city had allowed the violation to occur.

Holman said she hasn't seen any project that had come in front of the council that's been "this much of a conundrum in many years." She struggled with the idea of "grandfathering" a development that was illegally established without the city's knowledge.

Their opposition proved moot, however, as their other five colleagues voted to certify the document. The 5-3 vote was followed by a 7-1 vote to approve the project.

Newly elected Mayor Pat Burt praised the project's ample parking and sustainable features, calling it a "very exemplary project." The project will include 887 parking spaces, 539 of them in a new garage. Burt also lauded the glassy design of the new buildings and indicated that he won't miss the existing structures.

"We may have to lose this fine example of Stalinist Revival architecture, but I'm willing to let it go," Burt said.

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