Roughcast is a coarse plaster surface used on outside walls that consists of lime and sometimes cement mixed with sand, small gravel, and often pebbles or shells. The materials are mixed into a slurry and are then thrown at the working surface with a trowel or scoop. The idea is to maintain an even spread, free from lumps, ridges or runs and without missing any background.

According to the Encyclopædia Britannica Eleventh Edition (1910–1911), roughcast used to be a widespread exterior coating given to the walls of common dwellings and outbuildings, but it is now frequently employed for decorative effect on country houses, especially those built using timber framing (half timber). Variety can be obtained on the surface of the wall by small pebbles of different colors, and in the Tudor period fragments of glass were sometimes embedded.

According to the Encyclopædia Britannica Eleventh Edition, the central tower of St Albans Cathedral, built with Roman tiles from Verulamium, was covered with roughcast believed to be as old as the building. The roughcast was removed about 1870.

Pebble-dashing is a type of roughcasting where the surface coating is of small stones, chips of stones or gravel that are thrown at a coat of wet plaster while it is still 'soft'.

Roughcasting incorporates the stones in the mix while pebbledashing adds them on top.

See also

• Plasterwork