Building facade failures in the urban environment

Abstract

In the urban environment, building facades can be exposed to conditions that are not present in other environments. These include acid rain, higher atmospheric carbon dioxide and other agents that can deteriorate or attack the facades of city buildings or other urban structures. Sulfurous, sulfuric and nitric acids present in polluted air dissolve calcite minerals in marble and limestone facades or in concrete and mortar aggregates. Harsh cleaning chemicals or methods used to wash away city soil and soot can damage facades. Sealants can degrade and discolour from airborne deposits and contaminants. Facades may suffer impact and abuse from adjacent building construction activities. While failure of building facades or their connections can result from countless causes, the extent and consequences of such failures are often exacerbated by pollutants and chemicals that are commonly present in the urban environment. This paper addresses special considerations, conditions and risks that are associated with building facade failures in cities. The majority of urban facade failure descriptions and cases presented in this paper are based on the author’s experience in the USA.