Why Were Old Bridges Covered?

Covered bridges are an idyllic symbol of rural America. These charming, often hand-built structures have been romanticized in popular culture for years, from Thomas Kinkade’s painting “The Old Covered Bridge” to the novel (and film adaptation) The Bridges of Madison County. Despite their dispensability in the age of concrete and steel, these old wooden bridges continue to be beloved landmarks, their distinct roofs making them easily recognizable even today. But what exactly led to their proliferation in decades past?

A covered bridge is exactly what its name suggests: a bridge with a roof and enclosed sides, typically constructed from wood. The reason for the covering is quite simple. While there are some theories — most likely with some truth to them — that the roofs were added to keep animals calm above rushing water, or to provide shelter for travelers, the real purpose was much more practical. Wooden bridges, which were common in the U.S. and Europe in the 18th and 19th centuries due to the abundance of timber, deteriorated quickly when exposed to the elements. Rain, snow, and sunlight caused the wood to rot or warp, compromising the materials’ integrity and reducing the lifespan of the bridge. Covering the structure protected the wooden framework and deck. By keeping the timber dry, the bridge’s life could be extended by decades. Uncovered wooden bridges might last just 10 to 20 years, whereas some of America’s original covered bridges, such as the Hyde Hall Bridge in New York’s Glimmerglass State Park, remain intact almost 200 years after being built.

Simply having a roof doesn’t necessarily make a structure a true covered bridge, though. Underneath every authentic covered bridge is its truss system, a network of beams, often in the shape of triangles, that distributes the weight of the bridge and the load it carries on its deck. The trusses, though rugged in appearance, require precision, and building one often took a whole village — quite literally. Dozens, if not hundreds, of skilled workers from the community were involved: sawyers to prepare the rough-cut logs, timber framers to properly place the beams, and stonemasons to build the abutments, to name a few.

While the bridge coverings were primarily a form of protection, they also became symbols of, and important to, the communities that built them. They served as gathering places and even inspired local lore — such as the tradition of couples sharing a covert kiss under the roof, inspiring the name “kissing bridges.”

Covered bridges began appearing in the United States in the early 1800s; one of the earliest and most famous examples was Philadelphia's Permanent Bridge, built by architect Timothy Palmer over the Schuylkill River in 1805. By the mid-19th century, covered bridges were a common sight in the American countryside; estimates suggest that as many as 10,000 were built by the peak of their popularity in the 1870s. Though they’ve become emblematic of bucolic Americana, they weren’t unique to the U.S. In ancient China, for instance, covered bridges — known as corridor bridges — served as multifunctional structures, housing community events and shops, or providing a place to rest. Similarly, covered bridges in Switzerland, such as the artwork-adorned Kapellbrucke (or “Chapel Bridge”) in Lucerne, have been around for centuries and remain admired for their intricate designs and historical significance.

While covered bridges were once a common sight across the American landscape, fewer than 1,000 remain today. Despite the protection and reinforcement a covering offered, it wasn’t always enough in the face of floods, fires, or neglect over time. Remaining structures in states such as Pennsylvania, Vermont, and Indiana continue to be preserved and restored, connecting travelers not only to the other side of the river, but to the past.