Expert committee of architects issues ruling after New York building and Chicago's Willis Tower had been locked in dispute

The Willis Tower, left, and One World Trade Center. Photograph: AP

One World Trade Center has been officially crowned as the tallest building in the western hemisphere after a row that threatened to embarrass the building's designers and see it demoted to second place.

The debate centred over whether the 408ft steel structure on top of the New York skyscraper was a spire or an antenna. Supporters of the Willis Tower in Chicago argued it was an antenna, and so the building was only 1,368ft, rather than its stated height of 1,776ft. 

But the 30 members of the Council on Tall Buildings and Urban Habitat's "height committee", who met on Friday, ruled that One World Trade Center reaches 1,776ft and its claim to be the tallest building in the western hemisphere is legitimate. 

"We were very clear that it was a spire and not an antenna," said Timothy Johnson, chairman of the Council on Tall Buildings and Urban Habitat at a press conference in New York City on Tuesday. “Spires, we feel, are part of the architecture of the building that will not only be there permanently but have a significant effect on what the building is perceived to be,” Johnson said.

The chief architect of One World Trade Center, David Childs, had insisted that the height should be recorded at 1,776ft. He gave a 15-minute presentation to the council as part of its decision-making process. 

Johnson said the council had studied Childs’ plans for the building, and noted the symbolic height of the spire and the beacon that will shine from it – which is designed as a complement to the light at the top of the Statue of Liberty in New York Harbour. “So conceptually it is definitely, from the architect’s point of view, a major part of the building, and we agreed," Johnson said.

He also noted that the spire was a "permanent part of the building" and not an antenna, a flagpole or a sign. "There are no antenna emitting equipment on the spire," Johnson said.

There had been speculation the council might change its criteria to allow antennas to be part of a building's height, but this did not factor in the decision, said Johnson, who also a partner at the NBBJ architecture firm. "When we reviewed our height criteria we determined independently that out height criteria was fine. So there was nothing that needed to be changed regardless of One World Trade."

Timothy Johnson, chairman of the Council on Tall Buildings and Urban Habitat, announces his group's determination of One World Trade Center as the tallest building in the United States. Photograph: Kathy Willens/AP

Since One World Trade Center reached its full height, when its 408ft steel spire was installed on 10 May, there has been a growing lobby that argued that the Willis Tower, formerly the Sears Tower, was actually taller.

In original design for One World Trade Center, the spire was to have been covered in decorative cladding. That cladding was ditched during construction due to issues over its upkeep, however, which had lead, in part, to the contention.

Without its spire, One World Trade Center measures a mere 1,368ft, shorter than the 1,451ft Willis Tower – formerly the Sears Tower. The Chicago building has antennae on its roof, but these are not counted as part of its overall height. The top floor of the Willis Tower, at 1,354 ft, is higher than the One World Trade Center’s top floor at 1,268 ft.

The debate was particularly charged because of the symbolic nature of the metal structure on One World Trade Center. With the structure the building reaches 1,776ft – a reference to the year of the US Declaration of Independence.

Johnson said the council was not influenced by the 9/11 and the significance of the 1776ft height, however. "I had to make absolutely certain that this building was 1776,” he said. "If it was shorter we wouldn't have been shy to say that."

One World Trade Center is part of a complex of buildings being built in Lower Manhattan on the site of Ground Zero, replacing the original One World Trade Center, also known as the North Tower, and Two World Trade Center – the South Tower – which were destroyed in the 9/11 attacks. The so-called Twin Towers were the tallest buildings in the world when they were completed in 1971, before being overtaken by the former Sears Tower in 1973.

The owners of the Willis Tower had previously said they would accept the decision of the council on tall buildings and urban habitat.

Asked by the Guardian what would happen in the unlikely event of the owners of the Willis Tower installing a taller permanent structure on top of their building in a bid to regain the title of America’s tallest building, Johnson said: "Well we'd have to consider it. Of course."

> via TheGuardian