Like people, buildings age. Even under the best of circumstances, weather – particularly water, in the form of rain, snow, and ice – followed by or combined with extremes in temperature can do permanent damage to facades, cornices, parapets and other ornamental features, as well as to rear and side elevations. These problems can be exacerbated by design flaws or neglected maintenance. Often, it’s not until a thorough inspection, a leak issue – or worse, an incident where something falls from a facade and strikes someone on the ground below – that the signs of a problem become evident. That’s why it’s so crucial that the signs are noticed before damage is done.
The Causes of Facade Deterioration
“Structurally, a lot of issues we come across may be due to improper design,” says Rhocel Bon, a senior associate at Klein & Hoffman, a national engineering firm with offices in Chicago and Philadelphia. “We see flaws resulting from design, and even more from lack of maintenance, or deferred maintenance. With a brick building for example, if there isn’t a tuckpointing program, you’ll find that after some years, the mortar joints start to weather. Water enters the wall cavity, which can cause problems to the underlying steel.”
Tuckpointing is a maintenance method for mortar joints that involves removing the outer inch or so of existing mortar and replacing it with new mortar. The existing mortar must be tested first, to insure that the strength of the new and old mortar is the same. Bon explains that applying replacement mortar that is stronger than the original material will only cause additional problems. The same is true of the converse; the new mortar shouldn’t be weaker than the old mortar either.
“Most of the time, the biggest factor in New York City — as well as other cold climates — is the freeze,” says Eric Janczyk of Nova Restoration, a facade maintenance and restoration company located in Brooklyn, New York. “Both heat and cold have their own issues. In winter, you have the snow and ice hitting the building, and moisture can infiltrate the building. Then it freezes up and can expand, causing pressure from within the walls, that can in turn cause areas of the facade to bulge and displace. Rain can also get behind the bricks, which can create structural issues behind the facade. Exposure to the elements – sun, wind, rain, and snow – impacts sealants, making them age more quickly. The sealants can become ‘gummy.’ This is especially true on east-facing facades and elevations. Be it cold or warm weather, water can then cause erosion of the underlying steel.”
Another cause of deterioration on facades is pollution, though that damage is mostly aesthetic. The effects of pollution on stone – particularly limestone – are well known. It can turn the normally buff-colored stone black. The stone is porous and made more so by the effects of pollution, further weakening the facade and facilitating water infiltration leading back to the problems described above.