Manufacturers Beyond Code
like Bill Robinson's assessment of building codes as "bare minimum" and his likening the code to getting a D grade ("Weather Barriers for Coastal Conditions," January/February 2008; www.coastalcontractor.net). One of the places where I see some improvements with the code is its deferral to product manufacturer installation instructions.
Take, for instance, IRC 2006's R613 Exterior Windows and Glass Doors. It states: "Windows shall be installed and flashed in accordance with the manufacturer's written installation instructions. Written installation instructions shall be provided by the manufacturer for each window." This is pretty powerful when you stop and think about it. Instead of trying to address the umpteen different window styles and possible installation details or coming up with a "one size fits all" solution that is typical of a prescriptive code, the responsibility is placed on the installer and the manufacturer. Many window manufacturers provide very good installation instructions for their products. The instructions usually comply with the AAMA guidelines / ASTM E-2112 and are certainly easier to navigate. In the past, many manufacturers of building products dropped the ball when it came to providing thorough installation instructions. Now I see more and more companies showing details of how their products integrate with others for a complete "systems approach." Going "Beyond Code," as Clayton DeKorne suggests in his editorial (January/February 2008), can also involve manufacturers — not only through the products they provide us but also through well-drafted installation instructions and education programs to support those products. Certainly, these instructions and training have to go beyond how to nail it to the wall or roof; they have to address how to integrate a given product with all the others to which it's connected.
East Greenwich, R.I.
Ted Cushman's article on corrosion ("Fasteners for Treated Wood," Soundings, January/February 2008; www.coastalcontractor.net) was the best I've seen in a long time. Question: What is the sensible fastener to use to frame vented attics near saltwater? Would HDG or even bright nails suffice because such an attic would remain mostly dry?
Editor's note: According to Prentiss Douglas, a research engineer with Simpson Strong-Tie, there has not been a lot of real-world testing that tackles this exact issue. But Mr. Douglas did point to one study done in Hawaii that examined corrosion on steel framing in vented attics, where the framing was protected from the rain but not from the salt air. The steel sections were G60 galvanized — the minimum available (Simpson Strong-Tie has gone to a minimum of G90) — and considerable corrosion occurred after just a few months at the coastal sites. The inland sites saw less visible corrosion over the same duration. The authors of the study recommend increased galvanized thickness for framing members and fasteners in vented attics, but the exact level will depend on the specific site. After exploring this issue, my inclination would be to use a G185 (such as Simpson Strong-Tie's ZMAX) or stainless steel for connectors at the plate line of a vented attic on beachfront property. For framing nails, and even truss plates, it's less clear. But given this issue, and the potential for storm winds blowing out the soffits and drenching homes (see "Securing Soffits," January/February 2007, and "Understanding Water Intrusion," Soundings, March/April 2008), an unvented attic seems like the best way to go.