Historically, exterior walls on commercial structures consisted of multiple courses of masonry (mass walls) finished on the interior with plaster or other finishes. As construction evolved and the need for more energy efficient buildings grew, exterior wall technology and practice changed dramatically. Today, most exterior walls are very thin in comparison to mass walls of the 19th century and have considerably more insulation, air barriers, drainage components, and multiple, complex cladding systems integrated with curtain wall and other components.
Cladding technology and components have proliferated considerably over the last 10 years. While all this can be mind-numbing, there are two primary cladding types to consider: is the wall assembly surface-sealed or moisture-managed? Surface sealed cladding means exactly that: moisture is not intended to penetrate beyond the exterior surface of the cladding. A moisture-managed cladding is one that will manage and control moisture that penetrates beyond the exterior surface to a drainage plane safely back out to the exterior of the building.
An exterior wall consultant can assist with assessing various cladding systems and combining them into one, functional façade. This can be very complex if surface-sealed systems are used in conjunction with moisture-managed systems on the same elevation. Add code-required air and vapor barriers, continuous insulation requirements, fire resistance requirements, and integration with roofing, windows, and below-grade or at-grade finishes, and it is easy to see the complexity of modern wall systems.