Roofs Over Rivers

For a hundred and fifty years, the covered bridge has been an old American landmark. Today it is becoming increasingly difficult to find even one, but only fifty years ago the traveler encountered countless numbers of them—at cities, villages, and country crossings from Maine to Georgia and west to California.

The village bridge of the past century was the meeting place of town and country. In its dim interior men argued crops and politics while their womenfolk exchanged gossip and recipes and their children exclaimed over the gaudy circus posters that hung in the bridge long after the show had left town.

Out in the countryside a covered bridge was a good place to save a load of hay in a sudden summer shower. Farm boys found favorite fishing spots in its shade. It seemed as though a high-spirited mare could actually read the signs that were posted prominently over the bridge portals: “Five Dollars Fine for Riding or Driving Faster Than a Walk on This Bridge!”; for often as not she would automatically slow to a sedate pace on coming in sight of the cool, timbered passageway. For years the covered bridge was the country cousin to the city amusement park’s Tunnel of Love. The longer the bridge, the better. Just ask grandpa why they called them “kissin’ bridges.”

But how did bridges come to be covered? To provide shelter for the traveler, some say. Others think the housing presented a homey, barnlike appearance to horses, and thus prevented them from shying at the glint of river water. Actually, the explanation is far less romantic: bridges were originally covered, as one old New Hampshire man put it, “ter perteck the underpinnin’,” the framed wooden trusswork. With the rot caused by continual wetting and drying thus avoided, covered bridges have continued to give useful service for periods that amaze modern engineering experts.

American bridge-designers did not invent roofs for bridges. From biblical days onward builders have added roofs to their spans. In ancient times the purpose was mostly decoration and the protection of the people who crossed them. In Italy. China, and Mexico today, there are stone bridges with wooden roofs, used as market places. Village carpenters in Switzerland and Germany, however, seem to have been the first to evolve the idea of a roof to protect the timbers of the bridge itself; in heavily forested central Europe, covered bridges were built as far back as the Middle Ages.

Americans did not adopt the covered bridge until after the Revolution. In a fast-expanding country where the main routes of transportation crossed a number of broad rivers, stone bridges were too expensive and took too long to build. Since there were vast uncut forests in the eastern states, the giant virgin timber became the bridgebuilder’s material.

The contribution of American designers was the wooden truss, which could carry bridges of a length undreamed of in Europe. The pioneer bridges in America were simple affairs of short trestles set on piles, built to make fat profits from tolls. These were successful in places like Boston, but what sufficed for the placid Charles River was not enough for other coastal cities with swift and navigable streams to be spanned. The need was for sturdy, longer bridges without intermediate supports.

Some of the best minds of the time set to work on the problem. A bridge to span the Schuylkill River at Philadelphia engaged the attention of political pamphleteer Thomas Paine, for example, and he worked out various models, both in wood and—an unheard-of material for bridges—iron. For lack of money, however, nothing was accomplished. The same project also fascinated Charles Willson Peale, the eminent artist, whose famous museum was devoted to developing many of the arts and sciences. He put a Paine model on display and set about designing one of his own. Peale’s plans never got beyond the model stage either, but in 1797 he wrote an “Essay on Building Wooden Bridges,” and was awarded the first United States patent for a bridge design. Charles Peale’s heart was in invention alone, not in engineering, so he turned over the patent rights to his gifted but ne’er-do-well son Raphael. The younger Peale, who had tried his hand unsuccessfully at many other jobs, attempted to build a full-sized bridge on his father’s plan at Beaufort, South Carolina. It collapsed before completion, and Raphael, always ready with an alibi, blamed the failure on “hiring too many Yankee workmen!”

But up in Newburyport, Massachusetts, another “Yankee workman” was more successful. He was Timothy Palmer, a local shipwright’s apprentice. Wooden arches, made of huge squared timbers lapped and mortised together, were his answer to the long-span problem, and he became their first successful designer. Palmer must have come across a copy of an old Italian architectural book by Andrea Palladio, who in the 1550s had devised and built arched wooden-truss bridges over tiny Alpine torrents. Timothy Palmer translated the Italian’s brainchild into great timber arches made from the giant stands of pine in the New England forests.