The popularity of the Round-Roof barn dates from the 1920s, with most being built in the period between the world wars. The Round-Roof barn design came from attempts to optimize loft space for the storage of hay. Efforts to increase loft area for the same floor space largely brought about the increasing use of gambrel barn roofs at the end of the nineteenth century and towards the even more efficient round roofs in the early twentieth century. The curve of the roof, often parabolic, can vary widely. The height of the side walls may range from a short extension of the foundation to a full sidewall with the round roof forming only the roof. The eave is often broken by a tall entrance door. This roof configuration is sometimes called Gothic, Gothic-Roof, Arched-Roof, or Rainbow-Roof.
Pre-World War II barns with this type of roof configuration are not common in Colorado. They are widely and thinly distributed across the U.S. and most likely to be encountered in the Mid-west, especially in areas of late settlement such as northern Wisconsin. They are most often found in dairying areas where the increased hay storage of a round roof is advantageous. The Round-Roof is considered to be a barn type, but many different barn types have been roofed or re-roofed, with round roofs of laminated rafters.
Round-Roof barns without sidewalls became increasingly common after 1945, imitating the design of the popular World War II Quonset Hut.