A render is a mortar consisting basically of cement and fine aggregate, usually together with lime or a plasticizer, which is applied to a wall surface, generally in two or more coats.
When correctly matched with the background, the hardened render provides a durable weather resistant finish that will enhance the surface of a building.
Rendering is a traditional craft that has evolved over many centuries. Originally wattle and daub was used to fill gaps in walls constructed from wood or stone, to minimise the ingress of
wind and rain. A drawback of these early mortars was their inability to prevent the ingress of water, which was partially compensated for by having roof overhangs and adequate drainage at
the base of the wall. The development of Portland cement led to a mixture of cement and sand being applied to the external walls of structures, both for protection and decoration.
Historically, in some countries there has not been available the range of suitable indigenous facing material to construct external walls and rendering has been used for this purpose. A
walk around some of the towns and villages in the UK will provide testimony to the wide range of rendered finishes that may be produced.
