Ithiel Town Sold Bridges by the Foot

On January 28, 1820, a New Haven architect named Ithiel Town walked away with a patent for what looks, at first glance, like a garden trellis. Crisscrossed planks. No arch. No massive hand-hewn timbers. Just sawn boards laid diagonally over each other and pinned together with wooden pegs.

It made him rich, and it changed what a wooden bridge could be.

The trellis that carried trains

Before Town, spanning a serious river in wood meant an arch — Theodore Burr's approach, essentially, where a curved timber arch does the heavy lifting and the truss rides along with it. Arches required big timbers, precise mortise-and-tenon joinery, and a master carpenter who knew what he was doing. That's expensive, and in 1820 the United States had a lot more rivers than it had master carpenters.

Town's lattice did away with all of it. His truss was a web of pine or spruce planks set at roughly 45 to 60 degrees, overlapping in both directions, sandwiched between horizontal chords built up from more overlapping planks. Everything was fastened with treenails — wooden pins driven through bored holes. No arch action at all. The lattice worked as a true independent truss, the first in America to do so, and because load traveled through dozens of redundant members rather than a few critical ones, a cracked plank here or there didn't bring the thing down.

The practical upshot: a village could hire local men, buy plank at the nearest sawmill, and put up a span that would have been beyond them a decade earlier. Town himself described the goal plainly enough — build quickly, from materials at hand, with workers who weren't specialists.

Photo by Sfoskett (CC BY-SA 3.0, via Openverse). Worrall Bridge, Rockingham, Vermont — built around 1870 by Sanford Granger and the town's only surviving 19th-century covered bridge.

A dollar a foot, two if he caught you

Town was not shy about collecting. He sent agents across New England licensing builders at one dollar per running foot of bridge. Get caught building a lattice without a license and the fee doubled to two. For a 150-foot span that's $150 in 1825 money — real but not ruinous, and cheap next to what the arch alternative cost in skilled labor.

The royalties poured in for two decades. Town spent the money on an architectural career that had nothing to do with bridges: he partnered with Alexander Jackson Davis in Town & Davis, helped popularize Greek Revival in America, and designed the North Carolina State Capitol. He also assembled one of the largest private architectural libraries in the country. A man funded by rural plank bridges, buying books about Athens.

In 1835 he patented an improved version — a double lattice with doubled chords, stiff enough for locomotives. Railroads used it heavily until iron took over after the Civil War. Vermont's Fisher Bridge in Wolcott, built in 1908, is a rare surviving double-lattice railroad span and the last covered bridge in the state to carry trains.

Where to see one

The showpiece is the Cornish–Windsor Covered Bridge over the Connecticut River, built in 1866 by Bela J. Fletcher of Claremont and James F. Tasker of Cornish. Two spans, 449 feet 5 inches, New Hampshire on one bank and Vermont on the other — the longest covered bridge in the country, and still open to cars. It was pulled apart and rebuilt in the late 1980s, reopening in 1989. The American Society of Civil Engineers has it listed as a historic landmark, which feels about right for a design whose entire premise was that you didn't need an engineer.

Photo by Sfoskett (CC BY-SA 3.0, via Openverse).

For the purest example, go to Shrewsbury, Vermont, and find Brown Bridge on Upper Cold River Road. It's 100 feet of Town lattice over the Cold River, put up in 1880 by Nichols M. Powers — the most accomplished bridgewright Vermont produced, and this was the last bridge he built. It was named a National Historic Landmark in 2014, cited as among the least-altered lattice trusses left anywhere.

Stand inside one and look up through the webbing at the daylight coming through in diamonds. Two hundred years on, a pile of plank and wooden pegs is still holding up a pickup truck.

Thumbnail photo by Ascended Dreamer (CC BY 4.0, via Openverse).