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Compliance with the following codes: • 2012 and 2009 IBC; and • 2012 and 2009 International Residential Code (IRC). EIFS: IBC Chap. 14, IRC Chap. R7 Weather resistance: IBC Chap. 14, IRC Chap. R7 Weather protection: IBC Section 1403.2, IRC Section R703.1 Figure 6 Whether or not there are issues with installing the WRB over the rigid insulation is an ongoing discussion within the industry. Figure 7 Should the exterior sheathing and rigid insulation (with taped seams) be installed atop the WRB? under the International Building Code (IBC), as “barrier systems.” In other words, they are not supposed to allow moisture to penetrate into the building envelope and accumulate. The following information comes from an International Code Council Evaluation Service (ICC-ES) report of a major EIFS manufacturer’s product: Granted, in a perfect world, EIFS would indeed work as a barrier system. However, walls do leak because of contractor error or issues with the installation of other products used in conjunction with the system. Therefore, since evidence showed moisture penetrated these systems, the EIFS industry’s decision to add a drainage plane to overcome the entrapped moisture problem is important. As this information was at one time proprietary and not widely disseminated, the requirement for and effectiveness of a drainage plane as a remedy for entrapped moisture is not fully appreciated by the construction industry. It is important to note this article is not intending to single out and disparage the EIFS industry. In fact, it should be seen as just the opposite—EIFS manufacturers have made significant strides in successfully remedying the entrapped moisture problem by adding a drainage plane. Further, it is critical to remember the entrapped moisture problem is not exclusive to just one type of building envelope system. The problem with two barriers Enter the new energy code requirements: the 2009 International Energy Conservation Code (IECC) for residential buildings and American Society of Heating, Refrigerating, and Air- conditioning Engineers (ASHRAE) 90.1-2007, Energy Standard for Buildings Except Low-rise Residential Buildings, for commercial buildings. (The 2012 IECC, requiring even stricter standards, may soon be adopted in some locations.) To comply, the building industry is specifying rigid board stock insulation to be applied outside the wall sheathing. In so doing, the industry may be unwittingly creating a system remarkably similar to the early 74 the construction specifier | september 2013 CS_September2013.indd 74 8/14/13 8:59:32 AM