274 Clarendon was designed by Peabody and Stearns, architects, and built in 1871-1872 by Weston and Shepard, masons, and Grimes and Murray, carpenters.
Plans for the house are included in the Peabody and Stearns Collection in the Boston Public Library’s Arts Department (reference PS/MA.061). The drawings include two sets of floor plans each floor and a drawing of the north (alley) elevation, together with written specifications. The plans are dated October of 1871 and a reference to the contract between the builders and the owner (Augustus Flagg) is written on the outside of the plans.
These images, provided courtesy of the Boston Public Library, include both versions of the floor plans and the north elevation. The plans are fragile and in poor condition, and these images have been gently enhanced to reduce the stains and tears where possible.