That handsome building, seen above around 1876 when it was four years old, is the Bennett Building at Nassau between Ann and Fulton Streets. It’s still around, and known today for three things: it’s one of very few buildings with three full cast-iron facades, the trim on the cast iron is rather brightly colored, and it probably is (at ten stories) the tallest cast-iron-facade building ever built in the country. And in case you’re wondering about my ability to count to ten, here’s a picture from 1892, shortly after the building was expanded:
Both pictures are from the southeast, with Fulton Street on the left, Nassau Street on the right, and Ann Street beyond the building. What happened is straightforward: John Petit, a developer and architect, bought the building in 1889 and began to improve it. He worked on the interior and then in 1892 had the mansard roof removed and replaced by four new floors. The building had been tall before, now it was very tall. If you look closely, the water-table at the top of the sixth-floor windows is bigger than those at the other floors. That’s the original base of the mansard.
Cast-iron facades in general have a stability problem. They work well enough – as the hundreds of surviving cast-iron buildings show – but only because the buildings are generally short enough to not see full code wind load. Five or six-story buildings in Manhattan are generally well-sheltered from the wind. Since the wind stresses increase with height, and a ten-story building is more exposed to wind, the stability problem in the Bennett Building should be significantly worse. It’s not, and the secret to the building’s success is simple: the interior partitions that divide the space between stores on the ground floor and offices on the upper floors are brick bearing walls. The heavy structure is on the inside, leaving only the relatively open iron and glass at the exterior.
In the second photo, there’s a construction site in the left foreground, on the south side of Fulton Street. It’s got a frame of cast-iron columns and steel beams: you can actually see into the hollow space at the top of the square-section corner column. The spandrel beams – the ones at the edge of the building – are set back, so that they connect the inside faces of the columns inboard of the masonry wall. This won’t be a skeleton-frame building when it’s complete, because the frame doesn’t support the walls: it’s a cage frame, a hybrid of frame and bearing wall. And if that sounds vaguely interesting, wait until The Structure of Skyscrapers comes out.