Did you know that George Washington invented and designed a 16-sided treading barn for processing wheat on his plantation at Dogue Run Farm? It was in the fall of 1792, and the barn was desperately needed on Dogue Run, one of five working farms on Washington’s 8,000-acre estate.
“When Washington moved from tobacco to wheat as his cash crop, he faced the challenge wheat farmers have always encountered — that is, how to separate the wheat berry from the top of the wheat stalk,” explains Deborah Colburn, interpretive programs supervisor of the historic trades at George Washington’s Mount Vernon.
She notes that after wheat is harvested, the common way to separate the wheat berry from the stalk was to thresh it with a flail. “A laborer would literally beat the grain to separate it from the straw. This was very time-consuming and exhausting.” Fortunately, there was another way to thresh wheat: treading.
“The animals on the farm could walk over the sheaves of wheat and the impact of their hooves would separate the grain from the straw,” Colburn adds. “Treading was done outdoors, which exposed the wheat to the elements and mixed dirt in with the grain.
A significant portion of the grain was ruined or lost as a result. Both methods are fraught with problems in that once the wheat is harvested it must be kept dry. Processing the wheat out of doors left the crop exposed to fast-moving thunderstorms that could ruin a crop in moments. Washington could lose up to 20 percent of his harvest to soil and sky.”
The brilliance of the 16-sided treading barn was taking the most efficient method of processing — horsepower/treading — and moving it under cover, Colburn explains.
To learn more, watch our video featuring Colburn and three Grateful American™ Kids — AJ, Avery, and Callie. She takes these students from Longfellow Middle School in Fairfax County, VA, inside the barn for a history lesson. Don’t miss their excellent questions!
Be sure to scroll down for additional information about Washington’s barn by Dennis J. Pogue, PhD, adjunct associate professor in the historic preservation program at the University of Maryland.
GEORGE WASHINGTON’S BRILLIANT IDEA: THE 16-SIDED BARN
By Dennis J. Pogue, PhD, University of Maryland
By the fall of 1792, George Washington fully developed plans for the barn complex at Dogue Run, one of five working farms on his 8,000-acre estate.
The new barn was to perform the same function as the English-style barns Washington had been studying for many years — grain processing and storage — but in a radically different manner and with several novel features.
Washington was well-acquainted with using animals to separate grain from stalk by treading, and he had very specific goals in mind that he wanted to achieve.
Beginning with a simple concept — to construct a circular wooden treading floor large enough to accommodate horses that were enclosed from the elements of weather — Washington sought to improve the efficiency of this basic treading process and simultaneously reduce opportunities for theft.
The barn included a treading floor located on the second floor of a two-story structure that the horses could access via an earthen ramp.
Washington conceived of the innovation of leaving spaces between the floorboards so that the heads of grain, once separated from the straw, would fall through to a granary below.
There they could be temporarily stored in a central octagonal structure, then winnowed, and sent to the mill. The result was a building that was conceptually as much a machine as it was architecture.
Polygonal structures were unusual but not entirely rare in 18th-century Anglo-America. Although the shape was the structure’s most distinctive feature, it was not the polygonal shape of the barn that was Washington’s innovation.
Rather, the innovation was in taking an agricultural process and designing a structure to accommodate it. The roughly circular footprint was chosen to facilitate the treading of the horses. The reason for the structure being polygonal instead of perfectly circular in shape was due to the greater ease of constructing straight sides instead of curved walls.
The selection of 16 sides rather than any other even number is more difficult to explain, although it was also probably related to the octagonal shape of the interior framing system.
Since the treading floor was to withstand the weight and punishment of trotting horses, durable white oak was selected. Most of the remainder of the wood for the barn, except the roof and the ground floor interior octagon posts, was made of pine.
Although it appears steep, the slope of the barn roof (approximately 43 degrees) was not unusual for 18th-century buildings.
Roof pitches between 42 and 48 degrees were typical in this period. The steep pitch encourages faster run-off, resulting in less time for water to penetrate the wooden shingles.
Because the barn has an unusual shape, it must have been a difficult building to construct for Thomas Green, Washington’s carpenter, and the Mount Vernon slave carpenters.
One of the most important decisions Washington made was to design a building comprised of two nested polygons.
This refers to the 16-sided outside wall, enclosing the interior octagonal framing system. This design was the most straightforward way to support the roof since the same system for laying out the rafters could be continued from the eaves to the peak of the roof.
The transition from the exterior 16 sides to the interior eight meant that the structure of the roof had to undergo some subtle adjustments as construction continued upward, including the reduction of the number of rafters from 80 to 48. Since the rafters were the only structural members spanning that space, they served the crucial function of binding the exterior wall to the frame.
See the barn for yourself! Click here for information on taking the Visionary Farmer tour at Mount Vernon. During this 60-minute walking tour, learn about George Washington’s forward-thinking approach to crop rotation. As the landscape of Mount Vernon changes, the program’s focus varies to highlight different innovations and contributions throughout the year. Offered: Wednesday, Thursday, and Saturday, May-October 14, 2 p.m.
Dennis J. Pogue, PhD, has more than 30 years of experience working as an archaeologist, museum administrator, and historic preservationist in Maryland and Virginia.
He holds the Doctorate in Anthropology, with an emphasis in historical archaeology, from American University, in Washington, DC. He also consults to historical and historic preservation agencies, museums, and private citizens in the studying, interpreting, and preserving of their artifacts.