The primary function of a building is to exclude moisture intrusion from entering the interior surfaces; however, moisture intrusion is a common cause of building failures. Except for structural errors, approximately 90 percent of all building construction problems are associated with water in some way. Moisture intrusion can occur because of neglected maintenance, incorrect application of new building techniques or incorrect use of materials during new construction or restoration. Whatever the cause, moisture intrusion through leaks is a constant irritation to building owners and tenants.
This article provides an analysis of moisture intrusion in relation to exterior building components. It also provides proper methods of weatherproofing the building envelope.