This dissertation blends architectural history with disability studies to better understand the social construction of disability during childhood in the early twentieth century. Open-air schools and classes emerged as an educational experiment in the United States in 1904 and were abandoned by 1945. These spaces sought to improve the education of students with disabilities while enabling segregation based on their physical condition. The form and facilities of these classes varied depending on the class, race, and physical condition of the students, while responding to concerns about health, urbanization, and mechanical environmental systems across types. This dissertation examines the educational architecture of open-air spaces in four case studies focused in Chicago, New York, Baltimore, and Norfolk, to apply an understanding of local context to a phenomenon previously approached as a national trend. Open-air schools engaged with and complicated new approaches to school architecture and differing interpretations of "modern" in school design. Changes made to the school plant as a whole allowed for the reintegration of students in open-air classes as administrators further segregated children in other specialized classes based on physical condition. This dissertation argues that the diversity of conditions in United States' cities discouraged the adoption of a standard architectural expression for open-air classes while the diffusion of the classes promoted adoption of open-air features throughout typical schools. This failure of standardization to remedy child health concerns and diffusion of accommodations subsequently opened the way for more flexible approaches to school design in the mid-twentieth century. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]