It’s Not Invisibility

by Don Friedman on December 7, 2018

Beautiful, isn’t it? What is it? It’s the joint between two sections of a fire-escape handrail in Brooklyn. Each section has a frame around its perimeter made up of small wrought-iron angles, which are bolted to the balcony framing below and to each other at these seams. So the angle on the left is part of one section of handrail and the angle on the right is part of another.

Just about halfway up the left side you can see a small bolt shaft and nut, drowned in paint, where the two sections were connected. There’s just one problem: you can see air in the seam between the two angles where the bolt shaft should continue to the right. Here’s where the line of the shaft would be:

Oops. There’s no intentional deception here. Rather, there was a small bolt with its head on the right and the nut on the left. Small pieces rust faster than big ones because of that pesky surface-area-to-volume ratio, and in this case some rusting of the vertical angles may have also created a jacking force that put the bolt in tension, which would exacerbate any issues arising from rust reducing the bolt diameter. In other words, it rusted until the shaft broke and the head end popped off.

Probably someone should have noticed when repainting, but (a) it hasn’t been painted in a long, long time and (b) I’m not going to hold a painter responsible for any safety issues other than his or her own.

The moral of the story: a new bolt will be installed shortly.

Randomness Visible

April 24, 2018

Those pictures (click on them to enlarge them) were taken about six hours apart on the day of our last spring snowstorm. The truncated-cone roof is standing-seam copper and encloses an open, unheated mechanical space. If you look closely, you’ll see that the snow ends a bit short of the corner where the slope turns […]

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Point and Counterpoint

December 3, 2017

In the recent discussion of wood skyscrapers (full disclosure: I think they’re a terrible idea) I have noticed any discussion of the extent of exterior maintenance necessary to prevent wood from acting like the biological material it is. A masonry curtain wall can go thirty years with no maintenance and not fail: a lot of […]

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Brick Repetition

July 7, 2017

Some twenty years ago I described New York as the world’s largest laboratory for the destruction of brick. This view of midtown Manhattan gives a sense of why I said that. Except for a small amount of terra cotta and cast stone trim, and a stone balustrade off to the right, every inch of every […]

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December 15, 2016

That’s the view out my window in the new office. The facade of the building across the street is dirty. No big surprise, right? New York has many fine qualities, but cleanliness is not among them. But that facade dirt is a little more complicated than that. First, different materials show dirt differently. In this […]

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