We choose modern materials for their sharp looks and durability on boats and buildings. But if my friend is correct, maybe some of these materials are not so durable after all, meaning they won’t necessarily weather well. The difference from boats is that we can’t be expected to wash, polish, and wax our buildings. Buildings have to stand for the ages.

In small samples the cool new materials that we’re considering always look compelling. Nobody wants to think about how a material in a little sample will look after years of weathering on a big wall. But we should. We should ponder how our new high-tech materials will look five years, ten years, fifty years, even further out to the point when they’ve really been battered badly by sun and rain.

We need to be able to visualize how the colors fade and even, in some cases, will change hue and value. They may become pitted. They may become rusted, and on the surface they may have hard-to-remove streaks that are plain ugly. But that really doesn’t answer the most important question: how will the discoloration caused by weathering actually look on the building? Maybe it will be OK, assuming the envelope has not been compromised.

To figure this question out, we have to push harder and visualize the material over time in situ --that is, not in and of itself but on the façade subject to the incessant dripping, streaking, and splashing over time that will be imprinted on it. Will the weathering effect be handsome or ugly? Making that determination is the hard part, because you have to picture how every change of plane, or every bas-relief element on the façade, might direct water, and then you have to decide what kinds of marks the water will leave, and, finally, if they’ll look good or bad.

I offer a truism here: the more predictable and regular a façade’s bas-relief pattern, the more pleasing its weather streaking will be over time. For traditionally designed buildings where façade details are organized into predictable layouts of ledges, string courses, window sills, and water tables, weathering tends to underscore façade aesthetics. But for buildings with purposefully unpredictable exterior, geometries and protruding elements that are irregular or off-the-orthogonal, weathering probably will be harder to predict and almost certainly will be odd-looking.

The architecture of the University of St. Andrews in Scotland offers a case in point. Weathering of traditional façades there underscores rational layouts of windows and ledges. In contrast, the angular, irregular elements on the façade of Sir James Stirling’s 40-year-old Andrew Melville Hall, while extremely interesting in the abstract, have spawned patterns of discoloration and deterioration in the field from Mother Nature that I’m sure were unanticipated and that I believe do not contribute to a positive aesthetic effect.

This is no argument for traditional façade detailing, but an observation that weathering of façades is as much a factor with our shiny new modern materials as it ever was, if not more so, and that we ought to pay attention to the patterns that develop on them, for the effect can be a surprise.

Header photo credit: kkmarais via Wikimedia Commons