When we try to understand the evolution of buildings over time, there are certain visual clues that demand attention. One of them is things – architectural ornament, floor elevations, window patterns – lining up too well. The picture above, looking west on 22nd Street towards Park Avenue South, provides a good example. (I talked about another example, on lower Broadway, two years ago.)
The building on the left, partly obscured by the tree, is a reasonably normal late-Victorian office building for New York, with all the arches, water-tables, and different window patterns that era liked. The building on the far right is an early-twentieth-century loft, with some (but not much) ornament, big strip windows, and overwhelmingly rectangular and regular geometry. The little four-story building trapped between them is not quite either style, but this is where the red flag is waving: it shares a bunch of geometry with its neighbor on the left. The floor elevations are the same, the basic window sizes (see below) are the same, the water-table at the third floor matches, and some of the stone banding matches. Here’s a view looking to the east, taken from further down the block to the west:
The basic, almost square windows are subdivided on the bigger, older building with vertical masonry mullions making pairs of windows and, in some cases, horizontal masonry mullions to separate a transom from the main window. The newer, smaller building has much smaller metal mullions subdividing the squares. The color of the masonry doesn’t quite match, but that’s the result of differing maintenance: the smaller building is dirtier at the third and fourth floors and has been painted at the first and second floors. The smallest details are the most conclusive: the molding surrounding the third and fourth floor windows on the smaller building exactly matches the upper-floor window surrounds on the bigger building, the moldings on the second floor are a different pattern but also match, and the third floor water-table is an exact match.
In this particular case, the story is quite easy to find. The building on the left is fairly famous: it’s the 1893 United Charities Building, which was designed by R.H. Robertson. The building on the right is a 1915 extension designed by James Baker, Robertson’s nephew, who also removed the mansard roof from the original building to add more floors. The buildings have had separate ownership for some time, and the National Register nomination form lists the site as 150 feet long on 22nd Street, which means it excludes the extension.
There are, broadly, three approaches to an extension. First, you can match the original architecture so well that a casual observer will think the extension is part of the original. The 1993 addition to the former Felix Warburg house, now the Jewish Museum, is a good example of this. Second, you can deliberately contrast the addition so that there is no mistaking it for the original. The 1980s glass-walled west wings of the Metropolitan Museum of Art are a good example. These two examples are of some interest because they are about seven blocks apart on Fifth Avenue and because they have the same architect, Kevin Roche. The third approach is to pick up some architectural cues from the original but use enough originality to make the extension visibly distinct. It arguably requires the most skill because, if done poorly, it makes the extension look like a badly-executed example of the first approach, matching.