Code Interpretations

Donald E. Smith, CCS

July 2008

I have encountered a problem with a local building official and his interpretation of ASTM C1063 and the requirements for the installation of casing beads. The official says that we have to install metal casing beads in every location where there is a change in material. He also has stated that we need to install rope in the weep holes to facilitate the drainage of the wall cavity. Is this really what C1063 says?

It is helpful to start with the understanding that casing beads are considered accessories as defined in C1063. Paragraph 6.2.2 states: "Accessories shall be fabricated from Zinc Alloy (99% pure zinc), galvanized coated (zinc coated), steel, rigid PVC or CPC Plastic, or anodized aluminum alloy. See specification B221.” Attached to this paragraph is a note explaining that the type of material selected for use is governed by climatic and environmental conditions specific to the project location.

Paragraph 7.11 specifies the application of accessories. Casing beads are covered in paragraph 7.11.3 and reads as follows: "7.11.3 Casing Beads – Nonload-bearing members shall be isolated from load-bearing members, and all penetrating elements, with casing beads or other suitable means, to avoid transfer of structural loads, and to separate from dissimilar materials.”

My take on this is that the important item here is to isolate nonload-bearing and load-bearing elements of the structure as well as isolating dissimilar materials that penetrate the stucco. While casing beads are normally used, other suitable methods are acceptable to provide this function. In some cases this isolation can be obtained by the use of sealant joints. In the case of stucco, a termination point is required in the stucco system to provide a hard edge for the sealant system to work properly. Also as noted earlier, the casing bead need not be metal.

As far as using ropes to provide weeps in the system, this is not specified in C1063. In paragraphs 6.3.2 and 7.11.5 the function of and the application of a foundation weep screed is specified clearly. The use of ropes to provide drainage is not included in either of these paragraphs. I do recall that many years ago masons would use pieces of rope to define a weep hole in head joints for drainage. With all the new products available to provide drainage in masonry systems, I do not think ropes are used for this purpose. In any event, the ropes were removed after the mortar had taken its initial set.

I’ve been in the business for 35 years, and I have recently begun reading statements that say some products are "code compliant.” Is there a way to know for sure that when a company says their product meets code, that it really does meet the code? I know there are products out there that do not meet the standards of the building code, so how can I be sure I’m getting the right material?

I have to say that I was not aware that the International Code Council provides a list of "code approved” materials—because they don’t. I am also not aware of any materials that have a label that states "code approved.” In fact, if you take a close look at the stamps on a set of contract documents used for obtaining a building permit, there is a stamp that removes all liability from the building department that issued the permit.

The building code requirements for specific materials kick in when you encounter a life safety situation. Even then the code is not product specific because, in most cases, an assembly of materials is used to provide the necessary construction to prevent a threat to the life safety of the individuals involved. But there are exceptions: Fire rated doors and frames have a UL label affixed to the door and frame stating the hourly rating, as do some types of fire dampers. When we get into rated wall assemblies, this is not the case. These assemblies are just that—assemblies of materials from several manufacturers that when put together and tested in an independent testing laboratory, a fire rating is assigned to the design. The rating determines the how long the assembly will remain intact before the fire causes it to collapse. As we all are aware, when a given assembly is used it must contain the same materials that were originally tested.

How do you know if the correct materials are being used? For this example we need to look very closely at the assemblies and what was used in the original tests. Remember that the manufacturers pay the laboratories to conduct these tests, and the tests are not cheap. Most of the manufacturers are willing to make sure that the tested materials remain viable and available. In the case of tests conducted by the Gypsum Association, a significant number of them are non-proprietary and cover several manufacturers’ products, offering the specifier greater flexibility. You have to be aware of what products were included on the test and determine if the materials are still available in the marketplace.

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