A Case Study of Granite Cladding Distress

Distress of building cladding is either a symptom of an underlying problem within the support structure or is a sign that the cladding is deficient in some way. Cladding distress typically affects the appearance of the building, may allow unwanted intrusion from the elements to affect and degrade interior materials, and/or may allow the potential for unsafe conditions to develop if conditions are left uncorrected. Like other building components that fail, cladding distress develops from a number of factors that often involves more than just a single cause. The reason why cladding fails and the extent of this failure is a continued topic of debate among engineers, architects, contractors, owners of buildings, and our courts. Presented herein is a case of exterior cladding distress at a building that includes a search for reasons why the distress occurred based on forensic engineering methods and evaluation. This search concluded that the likely causes of distress for the subject structure were related to corrosion of embedded steel bars, differential movement due to dissimilar materials, excess water infiltration in conjunction with inadequate drainage at the exterior walls, changes in the as-built construction not represented on the plans, and inadequate design coordination/supervision prior to and during construction.