The 1916 Morris-Clark Barn in Van Buren County, winner of the Iowa Barn Foundation’s Award of Distinction, features canted cupolas and interior vertical supports that run to the roof, eliminating the need for large struts. It has been owned by the Clark family for three generations and is one of more than 100 barns featured in the 26th Annual All-State Barn Tour hosted by the Iowa Barn Foundation (IBF) Sept. 19-20, from 9 a.m. to 5 p.m. each day. The all-state tour highlights barns that have received matching grants from the IBF for their restoration and those that have received an Award of Distinction or Preservation Award for restoration by their owner. The self-guided tour is free and open to the public. For details visit iowabarnfoundation.org/barn-tours. Photos courtesy of Iowa Barn Foundation
Sept/Oct 2026 (Volume 18, Issue 5)
By Dave Austin
The barn cupola is one of the most recognizable features of Iowa’s historic barns. Placed at the roof’s highest point, it lets warm air naturally rise and escape through louvered openings. As that air vents out, it creates slight suction that pulls cooler air in through lower openings, increasing airflow and limiting moisture buildup. This simple, passive ventilation was especially important in early barns, before electric-powered ventilation reached rural areas. Beyond its practical purpose, it also added a decorative element to the barn’s overall design.
Cupolas first appeared on religious buildings in the Middle East and later in Europe, where they were largely decorative. European settlers brought this architectural idea to America and by the late 1700s began adding cupolas to barns to improve light and airflow. By the mid-1860s, better siding and roofing material made barns more airtight and moisture-resistant, increasing the need for structural sources of ventilation to release heat and moisture generated from fresh hay and livestock.
After William Louden patented the hay trolley-and-fork system in 1867, barns could be built larger and taller to house more livestock and store more hay. Storing more hay increased the risk of heat buildup from microbial activity, especially when the hay was harvested too wet. The resulting spoilage could escalate to spontaneous combustion and a catastrophic barn fire. Housing more livestock below also produced more warm, humid air from breathing, urine and manure. Good ventilation was essential to remove moisture and bring in fresh air—preventing mold in the hay and protecting animal health.
By the late 1800s, bovine tuberculosis cases had surged. “USDA Bulletin No. 7, investigations Concerning Bovine Tuberculosis,” stressed that good ventilation helps prevent infection by clearing contaminated air and reducing exposure to airborne bacilli. That guidance helped accelerate the use of cupolas to exhaust hot, humid, stale air from barns.
Cupolas were constructed from wood (top) through the early 1900s. Factory-made metal cupolas (bottom) became prevalent between 1900 and 1930.
Early barn cupolas were all wood, built by local carpenters and framed into the barn. They were sized to fit the building and used wooden louvers—angled to admit airflow while shedding rain and snow. By the late 1800s, blacksmiths added metal components such as tin or iron louvers and copper or sheet metal caps over wood frames. The biggest shift came between 1900 and 1930, when factory-made cupolas of galvanized steel and copper became widely available through catalogs and farm-supply companies. Cupola size, spacing and number varied with the barn’s dimensions, livestock count and hay-storage volume.
In the 1930s, rural electrification began reshaping barn design by enabling electric fans and ducted ventilation. By the 1940s, power was reaching more rural areas, and most Iowa farms were electrified by 1950. Around the same time, new barn construction in Iowa declined sharply—one reason many surviving barns still feature prominent cupolas.
Farmers took pride in their barns, and cupolas offered a chance to add personality and visual interest. Many are topped with a weathervane or finial for extra decoration. If you’re barnstorming during the Sept. 19–20 Iowa Barn Foundation All State Barn Tour, be sure to look up—you’ll see a wide variety of cupolas on display. The tour is free and open to the public, made possible by member donations. Learn more online at iowabarnfoundation.org/barn-tours.
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