Historic Structural Detail: Backless

During an apartment renovation in a converted 1860s loft building, a view of one of the cast-iron columns that makes up the front facade, as seen from inside: As is typical of these buildings, there’s a column between every pair of windows, so the iron makes up a grid of about 5 feet spacing horizontally and about 10 feet vertically (between floors). The shaft of that column – the 3/4 round and the engaged rectangular pier behind it – is one piece; the moldings and base plinth are separate, non-structural pieces screwed on. The fun comes when you look at the rear of the column head on: There’s a lot going on here… The horizontal channel on the left is an interior mount to hold a fire-escape on the outside face of the wall. The brick is not a structural wall, as it’s discontinuous vertically; it’s there to provide fireproofing that the iron does not. The thing that looks like a horizontal joint in the iron column, five brick courses above the floor, is…a joint in the column. Cast-iron…