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CSSBI Position Paper on CGSB Standards for Prefinished Sheet Steel Cladding The National Building Code of Canada 2010 includes references to two documents published by the Canadian General Standards Board (CGSB) dealing with prefinished sheet steel cladding. These documents are: • CAN/CGSB-93.3–M91 Prefinished Galvanized and Aluminum-Zinc Alloy Steel Sheet for Residential Use • CAN/CGSB-93.4–92 Galvanized Steel and Aluminum-Zinc Alloy Coated Steel Siding, Soffits and Fascia, Prefinished, Residential It is important to realize that there are no sheet steel products currently manufactured in Canada that meet the requirements contained in these CGSB standards. 

IntroductionSheet Steel Roong and SidingLightweight Steel FramingIsolate the Steel and Wood ComponentsAvoid Use of Pressure Treated WoodFastenersMany buildings will include wood members in applicationssuch as sill plates, splash boards, strapping, purlins, door orwindow bucks, and posts. In some of these end-uses it is arequirement that the wood be chemically treated (pressuretreated) to extend the service life.Designers and builders need to be aware that changes in theavailable wood perservatives may impact the durability ofany connected steel components or fasteners.Eective January 1, 2004 the Environmental ProtectionAgency (EPA) banned the use of Chromated CopperArsenate (CCA) as a preservative in treated lumber forresidential construction. This was done in an eort to reducethe use of chromate and arsenic thereby mitigating thepotential health and environmental problems. The woodpreservative industry has been switching to alternativewaterborne compounds including Sodium Borate (SBX),Alkaline Copper Quat (ACQ), Copper Azole (CBA-A and CA-B),and Ammoniacal Copper Zinc Arsenate (ACZA).Unfortunately, research has indicated that ACQ, CBA-A, CA-Band ACZA, the new generation copper-based products, aremore corrosive to galvanized steel than the former CCA.Since ACQ is becoming the predominant preservative in use,the discussions in this paper will refer to it exclusively.The purpose of this Fact Sheet is to convey the recommendations of the sheet steel industry for the application of steelproducts with ACQ pressure treated wood.