It is widely accepted that problems related to unwanted moisture are by far the most common and expensive of those encountered in building design and construction. The sources of unwanted moisture are as numerous and complicated as the building envelope systems employed in modern construction. The common avenues of water intrusion are familiar to all of us: roof and deck leaks, degraded sealants around windows and other penetrations, and seepage into basement areas through concrete cracks. Other leak sources are not so obvious and require careful evaluation of not only the individual envelope components (e.g., roofing membrane, wall cladding, foundation waterproofing, windows) but also the interface between components and their interaction with the HVAC systems.
Two building systems that encompass many of the water leakage problems suffered by modern buildings are roofs and exterior façades.
Roof Systems – Failures of roof systems occur more frequently than failures of any other aspect of building enclosures. Exponent has extensive experience investigating roof failures on both flat and sloped surfaces. Our experience includes the design and evaluation of built-up roofs, single-ply membranes, and sloped roofs using clay tile, metal, wood, and asphalt shingles. Our experience with single-ply membranes includes EPDM, polyvinyl chloride (PVC), modified bitumen, fluid-applied membranes, and a variety of insulation systems. In addition, our expertise with roof systems includes knowledge of material performance and the interaction between the roof and other building systems.
Cladding – Exponent’s experience with the performance of building façades encompasses building types from low-rise to high-rise and from residential to industrial. Facade types include wood, brick, and stone veneer; reinforced brick panels, pre-cast concrete, glass fiber reinforced concrete (GFRC), light-gauge metal, aluminum, and steel curtain walls; exterior insulation finish systems (EIFS); and natural stone cladding, such as marble and granite. All of these systems have unique construction methods and details required for reliable weatherproofing.
Exponent has determined the root causes of water leakage problems for thousands of buildings of all types of construction. The investigations often require comprehensive and multidisciplinary teams with specialized experience in construction methods, behavior of construction components, material science, and structural engineering. Specialized, custom-designed laboratory and/or in situ testing complement our expertise.