{"id":3343,"date":"2013-09-09T08:38:47","date_gmt":"2013-09-09T12:38:47","guid":{"rendered":"http:\/\/www.constructionspecifier.com\/?p=3343"},"modified":"2017-01-20T10:14:38","modified_gmt":"2017-01-20T15:14:38","slug":"claddings-and-entrapped-moisture-lessons-learned-from-early-eifs","status":"publish","type":"post","link":"https:\/\/www.constructionspecifier.com\/claddings-and-entrapped-moisture-lessons-learned-from-early-eifs\/","title":{"rendered":"Claddings and Entrapped Moisture: Lessons learned from early EIFS"},"content":{"rendered":"
\"All<\/a>
All images courtesy Masonry Technology Inc.<\/em><\/figcaption><\/figure>\n

by John Koester
\n<\/strong>While some building science concepts can be difficult to grasp, there is nothing new or complex about the relationship between temperature and moisture management. The phrases \u2018wet and cold\u2019 or \u2018warm and dry\u2019 are ingrained in the minds of the public for good reason.<\/p>\n

The law of physics dominating this phenomenon is thermal conductivity. Dense materials transmit temperature more efficiently than less dense ones because the molecules are closer together. Water is denser than air and transmits temperature 25 times more efficiently. When a person is wet, the ambient air temperature can be received more readily and the body loses temperature to the surrounding ambient air more easily if the latter is colder. A practical example can be found in the kitchen\u2014moving one\u2019s hand into a 200-C (400-F) oven, without touching any surfaces, is quite different from plunging a hand into boiling water.<\/p>\n

\"Controlling<\/a>
Controlling the temperature relationship of a building from inside to outside (or outside to inside) means insulating the exterior building envelope.<\/span><\/figcaption><\/figure>\n

Good thermal insulators\u2014sprayed polyurethane foam (SPF) and rigid boardstock, for example\u2014have 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.<\/p>\n

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\u2014the walls, floors, and roof (Figure 1).<\/p>\n

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.<\/p>\n

As shown in Figure 2, there are many causes of wet insulation in the exterior building envelope. Examples include:<\/p>\n