Masonry

A Difficult Corner

by Don Friedman on August 31, 2017


The stone tangle in the picture is the intersection of a church spire (background), and two different styles of turret (foreground left and right). You can see a bit of the scaffold pipe at the top and bottom and some plywood beyond on the right. For reference and mental picturing, this is all about a hundred feet above grade.

Strictly speaking, none of this is necessary. Use of the church by its congregation would not be impeded if the entire spire were to disappear tomorrow, although the building’s profile from the street would suffer aesthetically. The spire and its turrets and other projections are purely ornamental, meant to create a certain image from the street. That image is in the gothic style and is therefore inseparable from roughly a thousand years of architectural symbolism. In other words, the fact that the spire serves no physical function for use does not imply that it’s meaningless.

In terms of physical function, that’s a really awkward intersection of stone geometry. Five different sloped surfaces (the three you see plus the backs of the two turrets) dump snow and rain into that little valley. There is damage at the base of the turrets on either side from the drainage from the valley. In short, the geometry concentrates water into a small area from which it then has to flow out again. The water, of course, does flow out, but it’s damaging the masonry in the process.

There’s no obvious solution to the problem, other than to blame the people who designed and built this 120 years ago. There’s no way to add a gutter or drainage without completely destroying the visual integrity of the area. The logical thing to do would be to add a cricket, but that would also be visible as reducing the visual independence of the three elements (spire and turrets). Even flashing would be visible.

Sometimes the best answer is to do nothing. It’s been a long time since any repair work was done here and the stone has survived reasonably well. We can fix the damage, knowing that it will gradually recur and someone else will have to come fix it some time in the 2040s. The best thing about this solution is that it’s a way out of the metaphorical corner that trying to waterproof or drain the physical corner puts us in.

Gypsum Is Not Talc

August 29, 2017

I’ve mentioned gypsum block before: it was the masonry-style predecessor to gypsum board, a manufactured pre-fab substitute for rough-coat plaster and lath. The picture above (click to enlarge it) is from an early 1960s building. That’s a standard gyp-block partition in a mechanical room, serving as a fire-rated divider between two spaces. “Gold Bond” was […]

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Classic Damage Nicely Illustrated

August 28, 2017

It’s easy to come to the wrong conclusion here: it certainly looks like the mortar in the joints between the stone is being squeezed out, so that it projects from the stone face. Mortar of any kind doesn’t act like that – it’s not putty – but this is hard mortar with portland cement binder […]

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Composite Structure

August 21, 2017

That’s the side wall and an oblique view of the front of a small building on Nassau Street. The front appears to be early twentieth century, but the odds are good that this is an older building that has been modified multiple times. If nothing else, the storefront – visible as sheet metal at the […]

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Beautiful Brickwork Marred

July 25, 2017

Friend of OSE – and occasional collaborator – Glenn Boornazian sent me a few vacation photos from Massachusetts. That’s pretty nice masonry for an apparently abandoned building. In a non-aesthetic sense, the interesting stuff is going on near the eaves. That’s a damned big crack and displacement at the corner pier. The crack starts at […]

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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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Precise Terminology

June 2, 2017

Stretchers, headers, a few soldiers, and a few rowlocks: Common bricks are rough rectangular prisms, nominally eight inches long by four inches wide by a little less than 2-3/8 inches high. (More on the “little less” below.) The actual dimensions are the nominal dimensions less 3/8 of an inch to allow for mortar joints. Since […]

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Window Tracery As Structure

February 21, 2017

When a structural engineer tells a colleague that they are working on a window restoration project, the colleague might say, “But windows are not a structural element in a building, other than keeping wind and weather out.” That statement is correct; if you remove the windows from a building, the structural still stands. However when […]

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A Compromise

January 29, 2017

They’re not quite bricks and they’re not quite LEGO: Everblocks. I want them and I’m sure that I can find an empty warehouse somewhere to build with them.

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Mismatch

January 23, 2017

That picture shows a new wall being constructed in a historic building, replacing one that was badly damaged. We’re inside the building looking out; the half-height pier in the middle will eventually separate two windows. If you look closely at the pier (click on the pic to enlarge) you’ll see that the joints in the […]

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