During the teens and twenties, Watkin wrote articles for journals, primarily dealing with Houston, its growth and development, and the implications these held for the city's architecture. Watkin contributed descriptive pieces on the Rice Institute to Progressive Houston and the Southern Architectural Review, Houston's short-lived architectural magazine. Not until the late twenties did he become more involved in research and writing.
In 1930 the Rice Institute Pamphlet published a series of lectures Watkin had given on the new architecture in Europe; Pencil Points reprinted these in 1931. Watkin wrote two additional essays for Pencil Points, one published in 1931 on new directions in ecclesiastical architecture, and another in 1932. This former essay was something of a preliminary discussion to Watkin's first book, The Church of Tomorrow, published in 1936. In 1951 Watkin's second book, Planning and Building the Modern Church, was published. At the time of his death he was planning to write a book on architecture in Texas.