ROUGH CAST (the French equivalent is crepis), in architecture, the exterior coating originally given to the walls of common dwellings and outbuildings, but now frequently employed for decorative effect on country houses, especially those built in half timber. It is a composition of small gravel and sand, mixed with strong lime mortar, and is thrown on the walls already covered with two ordinary coats of plaster. Variety can be obtained on the surface of the wall by small pebbles of different colours, and in the Tudor period fragments of glass were sometimes embedded. The central tower of St Alban's cathedral, built with Roman tiles from Verulam, was covered with rough cast believed to be coeval with the building. The rough cast was removed about 1870.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)