Masonry facades

Although masonry construction has been around for thousands of years and its performance is generally well understood, the gradual departure from heavyweight construction to lightweight, framed structures with brick skins has brought about a range of problems that, until the 20th century, were unknown.

The widespread use of steel in building from the early 1900s permitted a gradual shift away from traditional heavyweight load-bearing construction to one of thinner, lightweight methods. Facades were no longer load-bearing (other than to support themselves) but formed a weatherproof and decorative enclosure. More recently, with the advent of improved thermal insulations, brick skins have become even thinner, with brick slips or tiles fitted to insulated carriers becoming a popular alternative to conventional masonry.

These lightweight forms of construction suffer from various intolerances - to building movements, to water penetration and to poor workmanship. Many of the failure modes discussed here apply to domestic construction as well as commercial buildings. Before investigating particular defects it is worth considering some of the properties of masonry and the structures to which it is attached. There are 3 principal considerations:

• water penetration;
• movement in the masonry; and
• movement in the structure.