Guidance on built-up walls - PDF

Built-up walls are essentially layered construction, often formed from components and materials from a number of different suppliers and manufacturers, installed in a series of independent operations by different contractors. This differs from traditional cavity wall construction whereby the two skins of brickwork would be constructed by a single contractor, at the same time.  

Although they have been used for around 100 years or so, built-up or layered walls have only become commonplace in UK construction over the past 30 years driven by a number of factors such as the requirement for increased levels of insulation; the desire for lightweight and economic forms of construction; and the availability of new materials. When designed, coordinated and constructed correctly they can offer a number of advantages over traditional forms of construction, however if detailed incorrectly serious issues may occur leading to degradation of materials and premature failure of the wall. Built-up wall systems utilising rainscreens and rendered wall systems (i.e. EWIS - external wall insulation systems) tend to be more complicated to design, procure and construct than other forms of layered construction and are the main focus of this document. 

This guidance document gives advice on the specification, design, procurement, construction, use and maintenance of these forms of built-up wall system together with their materials and components. It is intended for use by all those involved in the above processes from client, building design team, building envelope designers, principal contractors, specialist building envelope contractors through to end users.