Split-level houses — a multi-story modification of the one-floor ranch — became popular in the 1950s. Retaining the ranch’s horizontal lines, low-pitched roof, and overhanging eaves, the split-level added a two-story unit intercepted by a one-story wing. The resulting levels of interior space were separated into three distinct areas. The lower level commonly housed the garage, family room, and television. The mid-level wing contained the quieter living areas, and the upper level was reserved for bedrooms.
A wide variety of wall cladding and decorative detail can be found on split-level homes, although Colonial touches were more common than on their one-level counterparts. U.S. Census figures show that split-level homes have been all but eliminated in new construction, having gone from 12 percent of the market in 1975 to 1 percent in recent years.
Source: A Field Guide to American Houses, by Virginia and Lee McAlester (Knopf 2004)