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False Advertising

My stroll through the HABS/HAER index got me in one day from Fink Trusses to Flying Buttresses. That’s the Lafayette Square Presbyterian Church in Baltimore, built in 1879, changed to the St. John’s A.M.E. Church in 1929, and thankfully still there. It’s a very romantic Gothic-revival building, with one detail that nags at me. Here’s a better view of that right front corner:

There are two flying buttresses, one in the plane of the front facade (the gable-end wall) and one in the plane of the side wall. Both are structurally meaningless. In other words, they are not flying buttresses, which are structural elements critical to the stability of the buildings they are used in. Rather they are “flying buttresses” mean to evoke the spirit of those buildings.

First, the buttress in the plane of the side wall… Most of the load in real flying buttresses is the thrust generated by the gravity load of masonry vaults below the roof, with the rest coming from whatever lateral load there is. Except this building does not have masonry vaulting and if it did the vault thrust would be outward to the side. There is no reason for any eave-level buttressing on the front facade.

Second, the buttress in the plane of the front wall. This is less obviously meaningless, but it’s still meaningless. If there was roof vaulting, you’d need a buttress at every place two vaults meet, which is typically the centerline of the piers between the windows. There would be sideways thrust at the front facade, but only half as much as at the typical mid-wall pier; so if buttresses are not needed at those piers, they’re not needed at the front. The little extension of the buttress on top of the screen wall that has the gate to the side alley is not needed and, worse, is not in line with the main buttress and so not in line with the force it’s pretending to carry.

Third, that corner door… I don’t know the interior layout, but there are basically two possibilities. One is that you enter through this diagonal door and immediately have to make a 45-degree turn left or right. The other is that the pier at the corner isn’t a real pier, in which case the issue of fake load paths goes a lot deeper than those flying buttresses. Even if the first possibility is true, and the corner pier is there a few feet inside, the door makes it look like it’s not. And while that particular glass door is obviously a modern replacement, the presence of a door there is original.

I’m going to use what is, in some architectural-critique circles, a dirty word. This is mannerism.