Thermal performance of external renders applied to concrete blockwork

Abstract

The aim of this study was to investigate and analyse different external renders, available locally, and to study how their use may enhance the overall thermal performance of local concrete blockwork. This study provides an insight into how the various types of renders available improve the U-value of a concrete block wall. Three main types of external renders were used as the basis of this study. Results demonstrate that the ‘glass fibre additive’ type of render helped to greatly improve the U-value of a bare concrete block wall. This enhanced U-value, however, is achieved using more expensive render systems. Thus, from this study, the energy conscious designer can assess how, with the help of specific external renders, a more energy efficient building could be achieved, or how an existing building’s thermal efficiency could be improved. There are three aspects of performance that inform the selection of an external finish, namely: Aesthetic quality (colour & texture); Cost effectiveness, as compared to other types of finishes; Resilience to adverse weather conditions, particularly thermal performance. This paper investigates the issues relating to thermal performance, but also highlights the cost associated with choosing alternative but similar renders.