Proprietary render products differ from traditional render in that they are largely prepared off site (eg pre-mixed and supplied as a bagged product). Despite extensive use in continental Europe and the benefits which they can bring to projects, the use of proprietary renders in the UK remains limited. There is a lack of independent data on the performance of proprietary renders in UK conditions. This paper provides the results of laboratory tests undertaken on four proprietary products. Bond strength, resistance to water penetration and freeze/thaw durability of these products were all shown as being superior to traditional site mixed render; however, they showed reduced water vapour permeability. Proprietary renders offer many other potential benefits such as less waste, greater possibilities for machine application and fewer workmanship errors.

These improvements on the characteristics of traditional render are linked to factory production, and the ability to add and properly disperse beneficial components such as fibres and polymers