A Roof That's Patently the Best Option

A cross section showing the canopy's relation to the structural elements of the Old Patent Office Building.
A cross section showing the canopy's relation to the structural elements of the Old Patent Office Building. (Smithsonian Institution)
By Benjamin Forgey
Washington Post Staff Writer
Friday, September 9, 2005

Washington was spared a great embarrassment yesterday.

The National Capital Planning Commission, in another striking reversal, voted 9 to 2 to approve the elegant glass canopy designed by Pritzker Architecture Prize laureate Norman Foster to cover the courtyard of the historic Old Patent Office Building.

Three months ago, the same commission had voted 6 to 5 to reject pretty much the very same design, after twice approving the fundamentals of the design in 2004.

The way has now been cleared, in other words, for one of the more beautiful works of architecture and engineering the city will have seen in its 215-year history. Like the gossamer glass roof Foster and his London colleagues created for the Great Court of the British Museum, this one will be a technical marvel that will lift the spirits. It will transform a wonderful historic space in a most fitting and amazing way.

Not to build such a splendid, modern structure would have been a dumbfounding mistake. The error would have been noticed around the world, for sure. Today, architecture plays a significant role in establishing a city's competitive credentials. To turn down a wonderful building out of excessive caution or misplaced preservationist zeal? Definitely embarrrassing.

The Smithsonian Institution and the London-based firm of Foster and Partners did make a number of changes to the design before yesterday's vote, and these apparently proved decisive.

They changed the panels in the scalloped canopy to a clearer, more expensive, low-iron glass, and agreed to rebuild in some form the old exterior staircase on F Street NW. They agreed to reduce courtyard light levels during nighttime events. And, correspondingly, they pledged to light up the building's columned porticos and splendid stone walls.

But these are relatively minor adjustments. The lighting change will make a difference -- but not a big difference. At night, the roof no longer will have the "beacon effect" that so disturbed certain historic preservationists. To me, a subtle beacon effect would have been a fitting celebration of one of the city's best buildings. But losing it is by no means a major blow.

Fundamentally, the design remains the same. The roof will be the same height -- 139 feet 5 inches at its apex. It will retain its distinctive, technologically sophisticated shape, with three distinctive wavelike forms.

The innovative structure will stay exactly as designed -- eight steel columns on the courtyard's periphery, and a steel "edge beam" circumnavigating the courtyard behind its cornice. Not only does this preserve views of the historic courtyard walls, but it also enables the billowing roof to take on a sort of floating quality.

Though poetic and exhilarating, the shape of the roof also plays an important structural role. The aim, in an international competition held in February 2004, was to produce the lightest possible membrane to cover the courtyard. The "waves" of the roof contribute significantly to its capacity to span long distances with relatively lightweight steel frames.

The engineering quality of the Foster roof is especially appropriate for a building that was, in its time, an exemplar of American structural engineering. Robert Mills, its primary architect, created a daring, and lasting, system of brick structural vaults to support spacious interiors. Thomas U. Walter, Mills's successor, distrusted this system -- you can still see evidence of that in the iron reinforcing rods he insisted upon for the Lincoln Gallery's vaults. But the verdict of time has favored Mills.

Foster's roof once again will give life to the building's old informal title -- "Temple of Invention." The roof, however, will not be ready for opening day next July, said Sheryl Kolasinski, director of the Smithsonian's Office of Planning and Management, because of time lost due to the uncertainty over the design approval.

(The building has been shut down for major renovation since 2000. Both the Smithsonian American Art Museum and the National Portrait Gallery, co-tenants of the building since 1968, are scheduled to reopen on Independence Day 2006.)

"We'll have to get back in the steel queue," Kolasinski said, meaning that orders for custom-made steel elements such as those in the Foster design can be filled only by a few very busy fabricators. Kolasinski said that this and other uncertainties about supply, along with the difficulties of phasing courtyard construction once the museums are open, make it hard to predict a completion date for the roof. July 4, 2007, she conceded, would be optimistic.

Last month, the Smithsonian and the architects prepared five alternative roof schemes, and presented them informally to the commission. This seems to have had an effect on the voting -- each of the alternatives was much more disruptive to the original building than the one presented yesterday.

"In the realm of this world there is either going to be a roof or no roof, and if there is going to be a roof, the only one that made sense was the one they proposed," said NCPC Chairman John V. Cogbill, attempting to explain the commission's latest turnabout.

Cogbill's polite response masked much of the tremendous antagonism that had developed between the Smithsonian and historic preservation interests, in particular the Advisory Council on Historic Preservation. In April that federal body issued a scathing denunciation of the design and of the Smithsonian's actions in demolishing parts of the existing courtyard. This report, it seems clear, influenced some commission members to change their yes votes to no in June.

The commission also yesterday approved "the concept of a contemporary landscape design for the courtyard," although, in doing so, it could not help noting that the intent of the design should be to "recreate the public amenity that was lost with the demolition of the courtyard." That morsel of sour grapes aside, this action is a fine qualitative omen, for the courtyard landscape will be designed by the widely respected, innovative landscape architect Kathryn Gustafson.

© 2005 The Washington Post Company