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International Code, Local Interpretations

With the adoption of the new energy code and air and water barrier requirements, the Association of the Wall and Ceiling Industry felt the need for a program that would encompass all of these requirements, so AWCI is developing a new program in its Doing It Right series. Also in response to the new International Energy Conservation Code, the Foundation of the Wall and Ceiling Industry published a white paper in July entitled, “Navigating Uncharted Waters: Understanding the Energy Codes and How They Impact the Role of the Contractor.” This white paper, authored by Robert Grupe, is a must-read and has been mailed to AWCI members. It will also be available as a download from AWCI’s website.

My regular readers are aware of my feelings on the new codes and the effect on our work. Not only are we coming under more requirements that have a direct effect on production, but there is a cost impact as well. In many cases we do not have the knowledge and expertise to apply some of the cladding systems we have been using for years. The U.S. Department of Energy, in its infinite wisdom, has declared themselves cladding neutral. In other words, solving the installation problems associated with continuous insulation and water resistive barriers is being left up to the industry to solve.

One of the biggest problems encountered is the addition of a fluid applied air barrier or water-resistive barrier on the sheathing. Michael Logue of the Technical Services Information Bureau in Orange, Calif., passed along some of his concerns about this and the problems produced by less-than-stellar workmanship. Generally, his contractors install the sheathing and another sub applies the air barrier or WRB. The result is that there are water-trapping wrinkles and fish mouths leading to water intrusion when water passes through the primary WRB.

Another problem is the buildup of material along the edges where accessories have to be installed. This buildup results in an uneven surface to which corner and casing beads are applied. We all know what that means: uneven accessories and who gets blamed? Of course it’s the cladding contractor because our work looks sloppy. This uneven application of the WRB or air barrier affects not only stucco but any other cladding material applied to an uneven substrate.

Is there a solution to this problem? Absolutely. Michael did some research and found that a number of regions across the country recognize stucco or stucco and sheathing as an air barrier. He also discovered that the 2012 International Energy Conservation Code, in Section 402.4.1.2 entitled “Air Barrier Compliance Options,” does indeed offer options to comply with the requirements for a continuous air barrier for the opaque building envelope:

“Option 1 specifies materials with an air permeability no greater than 0.0004 cfm/ft2 under a pressure differential pressure of 0.3 inches of water gage (75 Pa) in accordance with ASTM E2128 and states that listed materials shall be deemed to comply. The Listed materials include XPS board 1/2 inch and greater, gypsum panels 1/2 inch or greater and Portland cement plaster (parge) not less than 3/8 inch.

“Option 2 address assemblies and drops the pressure differential requirement to 0.004 and accepts 1/2 inch of portland cement plaster.”

While the 2012 IECC has not been adopted nationwide with these options in a recognized code, the problems associated with sloppy workmanship can be eliminated. It seems to me that the approach would be fairly simple and the results positive for all concerned. Your first step is to contact your local building official and obtain a determination of their acceptance of the options contained in IECC 2012, even if they have not officially adopted the code. Better yet, if you have repeat clients that you do work for, approach them for assistance. This is also a valid value engineering item. My experience tells me that when you talk money, people listen.

While Michael was specifically addressing stucco, I believe this argument can be applied to any cladding system that incorporates the optional materials listed in the IECC. It is definitely worth the effort to investigate whether this will be accepted by local building officials. I know that state building officials in North Carolina and Virginia make interpretations of the code that have statewide implications. The International Code Council leaves interpretation of code language to the local authorities having jurisdiction.

If you are successful in gaining a favorable interpretation from a jurisdiction, please pass this information on to me and I will make it available in a database for other AWCI members to use in future work. The process will take effort and time, but in the end the ability to make use of the options in 2012 IECC will pay off big time.

Donald E. Smith, CCS, is AWCI’s director of technical services. Send your questions to, or call him directly at (703) 538.1611.

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