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Knowing the range of interactions amongst components in the exterior building envelope is not easy. Nevertheless, it is the specifying professional’s responsibility to research and determine what configurations will properly function. kitchen—moving one’s hand into a 200-C (400-F) oven, without touching any surfaces, is quite different from plunging a hand into boiling water. Good thermal insulators—sprayed polyurethane foam (SPF) and rigid boardstock, for example— have a lot of air molecules in proportion to other dense molecules; further, the former is effectively positioned between the latter to make this separation. A good example of this is the cardboard sleeve that slides around a paper cup of hot coffee, allowing someone to comfortably hold a steaming beverage. The clear takeaway for the building industry is to have an impact on a temperature relationship of a building from inside to outside (or outside to inside), one must insulate the exterior building envelope—the walls, floors, and roof (Figure 1). Another critical requirement is keeping the insulation material dry. Wet insulation is not an insulator, but rather a conductor. Different types of insulation materials absorb moisture at different rates. In many instances, an exterior building envelope with no insulation is preferable to one with wet insulation. Of course, the problems of wet insulation in a wall do not end with just poor insulation values. They also include mold, pest infiltration, and building material degradation. As shown in Figure 2 (page 70), there are many causes of wet insulation in the exterior building envelope. Examples include: • uncovered insulation stored in an exposed location on a jobsite can be installed in a damp/wet state; • liquid water can egress into the exterior building envelope during and after the construction phase; • moisture (in the form of water vapor) can enter the building envelope from the exterior and interior; • liquid water can leak from faulty plumbing; and • poorly insulated plumbing or HVAC ductwork can condense and drip water. Moisture problems with EIFS are often in areas where the system abuts other materials such as wood trim, at the top wall, at roof flashing, Figure 1 Controlling the temperature relationship of a building from inside to outside (or outside to inside) means insulating the exterior building envelope. around wall openings, and where other items penetrate the cladding’s surface. EIFS can also develop penetrations over time—foundations move, walls crack, storms can blow debris into façades, etc. There can often be installation issues. Even though manufacturers of EIFS products have recommended best practices and procedures, onsite labor does not always follow september 2013 | the construction specifier 69 CS_September2013.indd 69 8/14/13 8:59:16 AM