Still Boss
New York's Enduring Tweed Courthouse

The Tweed Courthouse restoration team repaired or replaced more than 1,500 pieces of marble across the entire building faŤade and replaced the entire 1,220-foot-long cornice, along with 335 modillions. To re-establish the main entrance, and to provide code-complying exits, the monumental Chambers Street stairway was rebuilt as the main entrance to the building.
Photograph by Michael Rogol

By Christina B. Farnsworth

The Building Stone Institute's 2004 Tucker award-winner, Tweed Courthouse, deserves recognition as New York City's second permanent government building (City Hall was completed in 1811). But that recognition rests on a lot of hard work and a great political story.

The hard work? The final, two-and-a-half-year push to complete the marble-clad building's total restoration. Architect Nancy Rankin said that the most difficult challenge was choreography to do so much work to meet the deadline. Rankin, co-author of the 2006 Tweed Courthouse book, said the cornice had to be restored in the reverse of its original construction; the modillions, originally installed first, had to be installed last.

Choreography also involved sending stone from the defunct original quarry in New York to Georgia for cutting. Computer-driven machines carved the modillions in New Jersey. Rankin said Shi-Jia Chen, B & H Art-in-Architecture, Brooklyn, N.Y., spent a year and a half on site carving stone.

If one counts the feasibility study starting in 1989 and early restoration efforts, Tweed Courthouse took almost as long to restore as it did to build.

Tweed Courthouse was under construction for 20 years, from 1861 to 1881. The Civil War did slow construction, but even The Great Conflict was merely another opportunity for the Tammany Hall (the New York City Democratic Party political machine that controlled local politics up to the 1960s) political boss William Marcy "Boss" Tweed and his "Tweed Ring" to line their pockets with embezzled public funds. Showing his flair for self-aggrandizement, Tweed decreed the edifice should bear his name in perpetuity. And it does.

The total cost was $11 or $12 million — costs are understandably fuzzy given that no one knows exactly how much the Tweed Ring skimmed. The money scandal finally broke, stopping construction entirely from 1872 to 1876. In a rare demonstration of poetic political justice, Tweed was tried, convicted and sentenced in his own unfinished courthouse. He died in jail in 1878.

Tweed Courthouse, constructed of Tuckahoe and Sheffield marbles, before the initial cleaning.
Photograph by John G. Waite Associates, Architects

John Kellum, the original architect, produced a fashionable neoclassical design, including a monumental Corinthian portico. Kellum's death in 1871 necessitated a new project leader, and Leopold Eidlitz carried forward, adding architectural elements of the newly favored Romanesque style. Thomas Little, a member of the New York City Board of Supervisors (as was Tweed), also is credited in the design.

New York City's Web site describes Tweed Courthouse as "Anglo-Italianate," an apt label for the Neo-classic/Romanesque stew that characterized American civic architecture after the Civil War. Others simply call the style "American Victorian." Whatever the label, the results were impressive.

Eidlitz made major changes, including changing an intended dome into a soaring octagonal rotunda topped by skylights. The rotunda extends from the first floor to the roof. Its east and west sides feature cast iron stairs from the first to the third floors. The "marble" pillars on these floors are really painted plaster and the "wood" railings are actually cast iron. "The Guide to New York City Landmarks" describes the building's mid-19th century interiors as "some of the finest ... in New York" and 20th century moviemakers evidently agree. Tweed Courthouse has starred in films, including "The Verdict," "Dressed to Kill," and "Kramer versus Kramer."

A century of use, pollution, remodeling and neglect dimmed the grand dame. Street widening in the 1940s demolished the original entry. The entire building almost fell prey to urban-renewal rubble in the 1970s, but a reprieve from the National Register of Historic Places dubbed the courthouse a National Historic Landmark in 1976.

Even so, Tweed Courthouse's shabby grandeur stood in muted molder until restoration began in 1989. New York City commissioned a feasibility study by Mesick-Cohen-Waite Architects in 1989. Now John G. Waite Associates, Architects, the firm both completed the study and served as architect of record for the decades-long restoration. So complex and demanding was the project that both the architects and construction managers, Bovis Lend Lease LMB, established full-time offices on the site in 1999, Rankin says. First in a trailer on the site and then, in 2001, inside the building.

The Georgia Marble Company quarry in Tate, Ga., supplied the replacement stone for the restoration.
Photograph by John G. Waite Associates, Architects

The exemplary restoration of Tweed Courthouse, now the new headquarters of New York City's Department of Education, took almost as long as the original construction and cost about 10 times more. A $90-million appropriation in 1999 financed the massive final push. Restoration culminated in 2003.

Cleaning and restoring the marble facades emerged as an early restoration complication. Key issues were cleaning, stabilization and repair of nearly 10,000 pieces of marble cladding.

Marbles from Tuckahoe, N.Y., and Sheffield, Mass., originally graced the temple-like exterior (the base of the building is granite). But exposure to a 100-year spectrum of atmospheric pollutants had veneered the marbles with thick, black gypsum (calcium sulfate). Marble reacts with sulfuric acid in the presence of heavy metals, according to the book "Tweed Courthouse: A Model Restoration."

New York's notoriously heavy industrial and vehicle emissions were key pollutants, even though many of these originated hundreds of miles from the building. The toxic crust was an amalgam of magnesium, nickel, vanadium and iron with lesser doses of chromium, aluminum, potassium, titanium and copper.

Although the entire building suffered, the black crust was worst on the north and east faces. To make matters worse, the crust became a corrosive poultice, holding pollutants to the stone and promoting further damage. As deterioration progressed, stone chunks began to fall from the building, prompting officials to remove vulnerable elements such as Icanthus leaves in hopes of preventing accidents.

Even less obviously damaged stone displayed "sugaring," in which the stone's surface simply falls away like dissolving sugar. And then there was the staining caused by bird-proofing agents — and the bird guano left as those chemicals lost their effectiveness. What a mess!

Window and wall details before restoration. Many of the marble decorative elements had been converted to gypsum by exposure to atmospheric pollutants and needed to be replaced by new stone.
Photograph by John G. Waite Associates, Architects

Even before cleaning began, Gianetti Studios, Brentwood, Md., spent five months making molds of decorative trims from the now fragile building ranging from simple modillions to a frieze panel. Preserving the decorative continuity was tricky in part because some building elements simply were gone.

Professor Norman Weiss of Columbia University came up with the chemical recipe for cleaning without harming the building's exterior. It took nearly 30 test panels to find the best method. Most effective and least damaging was a custom-designed alkaline gel (pH of 14) followed by an acidic after-wash (pH of 1.2), the Tweed Courthouse book reports. Even so, working through summer into New York's winter of 1990 required continuing modifications.

Archaeological-level inspection began after the initial cleaning. Consulting structural engineers Robert Silman Associates inspected, identified and referenced every stone block in the entire building with a unique alphanumeric code while noting every block's appearance and condition. One letter in the code represented a building side, the other a specific building section followed by the number of each block.

Restorers also sought to retain a bit of the patina of age while replacing heavily damaged and unsound stone. Structurally sound stone that showed age stayed; weathered decorative stone with missing edges stayed, too. "Dutchmen" from new and salvaged stone replaced missing parts and made repairs.

Finding replacement stone presented another challenge. Some played out quarries had been filled in and built over — but not the Sheffield quarry. Though it had been closed 125 years and the quarry equipment was gone, it had not been filled in. Moreover, more than 50 marble blocks lay scattered about the site. These abandoned blocks had been quarried for use in the Washington Monument, but the quarry operator was enmeshed in Boss Tweed's kickback scheme; Tweed's rising notoriety made the blocks politically unacceptable. The Monument order was canceled. The quarry land was now a farm. Rankin says the farmer was happy to sell the blocks, which were removed to Georgia for cutting.

Size was another issue. The Tuckahoe quarry had been known for very large blocks. Some original Tweed Courthouse cornice stones are 18 feet long. Today's stone cutting practices produce finished blocks between six and seven feet long.

Then, of course, came the challenge of color matching new marble to the remaining weathered original. Weathering samples from many quarries sat on the building's roof for nearly a decade to decide which would work best. Ultimately, Georgia White Cherokee won the weather test.

But by now it was 1999, and time to clean the building again. Brisk Waterproofing, Bridgefield, N.J., cleaned and restored, which included complete mortar removal and repointing.

The Chambers Street portico columns capitals during restoration. Craftsman anchored the newly carved sections to the original capitals using stainless-steel pins and epoxy adhesive.
Photograph by John G. Waite Associates, Architects

"More than 1,500 pieces of stone were repaired or replaced. ...The entire 1,220-foot-long cornice, along with 335 modillions, was replaced," the Tweed Courthouse book reports. Replacement work included replicating the original entry staircase removed for the 1940s street widening. Today, 17 new Vermont granite steps lead to the Corinthian portico.

Inserting new stone utilized modern installation techniques. The cornice blocks, for example, are anchored to the building with 3/4-inch diameter, six-foot-long stainless steel threaded rods. Rods fitted with plates, washers and nuts at both ends connect from the mid-point of each block through the building to its attic. Stone adhesives attach old and new stones. A new roof replicates the original metal roof.

Just because a building is old doesn't mean it never had ventilation. Ventilation shafts in the walls circulated cool air from the courthouse basement throughout the building. Restorers used these shafts to route modern heating, ventilation and air conditioning systems.

The courthouse renovation included its 30 monumental courtrooms. Stripping 100 years of paint — up to18 layers — revealed unexpected detailing in the ornamental cast iron and multi-colored patterns on the brick walls. Original paint schemes and marble and glass-tile floors popped into view throughout the building. New York has added the Tweed Courthouse interiors to its own list of historic landmarks.

Tweed may have raised political corruption to the status of art, but his love of massive public works schemes left some good in its wake. He improved water, sewage treatment and streets. And it is clear he loved stone buildings. His legacy includes other New York City landmarks, such as the Metropolitan Museum of Art, the American Museum of Natural History and the Brooklyn Bridge.

Christina B. Farnsworth is a freelance writer.

Resources
New York City Web site
www.nyc.gov/html/dcas/html/resources/man_tweed.shtml

"Tweed Courthouse: A Model Restoration," by John G. Waite with Nancy A. Rankin and Diana S. Waite. 170 pages, Norton, 2006.

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