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Cause and Effect

A reasonably pretty picture – I wasn’t trying for artistic effect, but I feel like I may accidentally achieved some – of a nasty situation. The exposed face brick is pretty much dead, since the outer hard skin of the bricks is gone, leaving the soft chewy centers exposed. When this condition was first exposed on this building I thought the problem might be the way in which the coating was being removed, but then I watched some removal and it was not. The workmanship was fine; the brick was already damaged.

There are two reasonably obvious narratives here. The first is that a hard and impervious coating was applied over soft nineteenth-century brick and bad things happened. The coating trapped water, the coating ripped the faces off the brick when there was minor thermal or moisture-related movement because it’s stiffer and well-adhered, the coating was too inflexible and cracked during minor movement and allowed water entry. The second is that the brick was damaged and a coating put over it, like a bandaid on deep wound. Both are bad, but in different ways.

Looking closely, the main problem is pretty clearly the second bad story. Where the coating is intact, it can clearly be seen following the shape of some of the damaged bricks, meaning that the bricks were damaged before the coating was applied. This coating is not flexible enough for it to follow the shape of bricks that weren’t damaged before application.

On the other hand, there’s nothing that says it can’t be both. If you apply a too-strong, impervious, inflexible coating so that it’s tightly bonded to already-damaged brick, the problems I listed as the first story will occur, and likely faster than if the brick had been in good condition before the coating. So the first story (coating damages the brick) can stand on its own, while the second (damaged brick was coated) can stand on its own or lead to the first.