The roof of the historic Benjamin Stephenson House in Edwardsville, Ill., was last replaced in 2001. But the staples prematurely corroded due to a reaction with the treated shingles. The replacement contractor, Taylor Roofing, and the consulting architects didn't want to repeat the failure. After investigating, they concluded that the problem was the pressure treatment of the wood shakes, reports Mary Cooley in the Belleville News-Democrat: According to the article, wood manufacturers, including the supplier that made the shingles in 2001, began changing the treatment formula to avoid lawsuits related to arsenic in pressure-treated lumber. "There was no regulation," Lynn Warren, of Henderson Architects is reported saying. "They used normal staples, and there was a galvanic reaction. The staples could be pulled right off ... any part of the staple in direct contact with the shingle was just gone."
Cooley goes on to report: "Wood and metal manufacturers have since figured out a combination that will hold, and Warren expects the roof to last the manufacturer's warranty of 50 years." But there is a problem with the lack of information in this statement. It might be construed that wood treatment companies have found a chemical formula that allows the use of ordinary staples. This is not so. The Cedar Shake and Shingle Bureau recommends using Type 316 stainless steel fasteners with all fire-retardant-treated or preservative-treated shakes or shingles. For more information, refer to the CSSB Roof Manual.
While not reported, it's likely that the replacement contractor and the architects used the correct fasteners.
