Introduction

Most buildings develop cracks in their fabric. This often happens soon after construction when many materials are drying out; sometimes it occurs later. Most early cracking is not structurally significant but it may be aesthetically offensive and rain penetration may be increased. It is easily repaired and unlikely to recur to any great extent. Only rarely does cracking indicate a reduction in structural capacity. Much can be done to minimise, or even avoid, cracking by recognising that movement of building materials and components is inevitable and must be allowed for in design.

Diagnosis of specific causes of cracking is often difficult; every building is unique and several factors may combine to produce the observed defect. Before repairs or remedies are considered, the following must be ascertained:

• the causes of cracking
• their effect on the performance of the building
• whether movement is complete, incomplete or cyclic (eg seasonal).