mansard roof, type of roof, so named because it was frequently used by the French architect François Mansart. It was not devised by him but was used early in the 16th cent., as in portions of the palace of the Louvre designed by Pierre Lescot. It became particularly characteristic of French Renaissance architecture and later was much used in Victorian buildings in Europe and America. The slope of a mansard roof from eaves to ridge is broken into two portions. The lower portion is built with a steep pitch, sometimes almost vertical; the upper portion has a low pitch or is nearly flat. This results in a higher and more useful interior space than can be obtained with other roof types.