CHICAGO — Water intrusion through the building envelope — including roofs, walls, windows, and foundations — is the leading cause of water damage in commercial buildings, accounting for approximately 40 percent of all commercial property insurance claims, according to data from the Insurance Information Institute.
Roof failures are the most common source of building envelope water intrusion in commercial buildings. Flat and low-slope roofs are particularly vulnerable, as they rely on drainage systems to remove water rather than shedding it by gravity. Clogged drains, deteriorated membrane seams, and failed flashing are the most common roof failure points.
Window and curtain wall failures are the second most common source of building envelope water intrusion. Deteriorated sealants, failed gaskets, and improper installation allow water to enter at the interface between glazing and framing. In high-rise buildings, wind-driven rain can force water through even small gaps in the building envelope.
Foundation water intrusion is common in below-grade spaces including basements and parking garages. Hydrostatic pressure from groundwater can force water through cracks in concrete walls and floors, particularly in areas with high water tables or poor drainage.
Building envelope commissioning — a systematic process of testing and verifying the performance of the building envelope — is the most effective way to identify and correct water intrusion vulnerabilities before they cause damage. Several states now require building envelope commissioning for new commercial construction above a certain size.
