Cracks result in when applied forces are greater than those which the building or its part can withstand.
These forces may have emerged externally to the building or internally within the building or have been developed in the materials of the building as a result of Chemical changes. There may be a single force or a combination of forces having a single cause or several causes.
Structural cracks could be due to major or minor problem in the structural design. Intensity of structural problem is determined on the basis of the intensity of cracks developed.