“Everybody thinks about masonry as just square pieces of clay, and the fact that you can actually make them into walls that are very elegant, sinusoidal or curved, it just puts a different perspective on what masonry can be,” says Brian E. Trimble, PE, LEED, AP, director of industry development and technical services for the International Masonry Institute.
Trimble knows a thing or two about crinkle crankle walls because he’s done a bit of research on the topic, having written a technical paper on the subject nearly a decade ago for the Canadian Masonry Symposium. “Of course, here in the U.S., they are usually referred to as serpentine walls,” he points out. It’s easy to see why. They’re shaped like a snake’s S-shaped slither. (The term “crinkle crankle” comes from the Old English term for “zig-zag.”)
The walls’ unique shape makes them stand apart, both aesthetically and in practicality. The pattern of concave and convex waves, known as a sinusoidal pattern, serves a number of important purposes. During the Middle Ages, it was discovered that undulating walls helped fruit trees grow better in cooler climates. The curves created pockets that protected the trees from the wind while also trapping heat from the sun and radiating it back into the trees, essentially creating a longer growing season, Trimble says.
Another benefit was cost. While the footprint of a wavy wall is much greater than a straight one, taking up more landscape, its design helps reinforce it better than a straight wall of the same material. In other words, serpentine walls can be made one wythe (a single brick layer) thick, while straight walls generally require two wythes. Thus, fewer materials are needed to construct a serpentine wall versus a straight one.
“Straight cantilever walls require reinforcing of a thicker wall with pilasters or piers located along its length to resist lateral loads,” Trimble wrote. Conversely, “serpentine walls can be infinitely long without a pier if the geometry is proper.”
And yes, the geometry has to be correct for it to work. In 1958, the Structural Clay Products Institute, now the Brick Industry Association, published a technical note on formulae for a serpentine wall’s geometric properties. The equations are based on radians and not degrees.
If you want to learn more, check out this explanation from John D. Cook, a consultant in applied mathematics, statistics and technical computing, who has studied and written about crinkle crankle walls.