Commercial Architecture October 2016 - 16

PROJECT exteriors T he nautical expression "to pass with flying colors" is derived from when ships would come back from battle with their colors (flags) flying to indicate they were victorious. On the Stimson Marina in Seattle this phrase has another meaning. The greenand-white-striped roof on Seattle's largest covered freshwater marina, located on Salmon Bay, is not only the marina's signature trademark, but it is also a geographical reference point to pilots. "If you can locate the Stimson Marina and/or the Space Needle, you know where you are," remarked Brent Howell, facility manager at Salmon Bay Center in Seattle, who oversees the Stimson Marina. Thus, when the C.D. Stimson Co. decided to replace the Marina's 50-yr.-old metal roof, it wanted to make sure the new roof was able to sport the same green and white stripes as the old roof. The new roof also had to be watertight to protect the 200 boats under its five docks, and installation of the roof had to follow environmental guidelines so as not to harm the salmon run that it abuts. WEIGHING THE OPTIONS Howell said they considered several options for replacing the old metal roof. "My initial thought was to tear everything off and put on a new metal roof," he explained. "But working over the boats and a myriad of environmental concerns regarding the water made that option not very feasible." Fortunately, building-envelope consultant Wetherholt and Associ- Marina Roof Passes With Flying Colors ates Inc. of Kirkland, WA, suggested two other options. One was to install a new metal retrofit roof on top of the old roof with sub-purlin framing, and the second option was to install an induction-welded thermoplastic single-ply membrane over a high-density cover board as an overlay system. Roofing contractor Axiom Division 7 of Lynden, WA, suggested using the Wooster, OH-based FiberTite RhinoBond roofing system for the second option. FiberTite is a reinforced membrane coated with a proprietary compound, using DuPont's Elvaloy ketone ethylene ester (KEE). FiberTite's four-layer technology includes an adhesion coat that Preserving green and white stripes that were a landmark for pilots and following environmental guidelines were just part of the challenge. fully saturates the base fabric, forming a molecular bond between the back and face coat, providing maximum resistance to delamination in the event of wind uplift. RhinoBond, designed for use with thermoplastic roofing systems, uses induction-welding technology to bond the membrane directly to specially coated plates that are used to secure the insulation to the deck, all without penetrating the roofing membrane. The result is a roofing system with improved wind performance that requires 25% to 50% fewer fasteners and plates and as many as 30% fewer membrane seams to weld on the roof. In addition, since the fastening points are spread out across the roof deck in a grid pattern rather than concentrated in the seams of the membrane, the wind-uplift load is distributed more evenly. The result is less point loading on each fastener, enabling the system to achieve higher wind ratings with fewer fasteners. Top. The new roof had to be watertight to protect the 200 boats under its five docks, and installation had to follow environmental guidelines so as not to harm the salmon run that it abuts. Left. The green-and-white-striped roof is not only the marina's signature trademark, but it is also a geographical reference point to pilots. 16 COMMERCI A L A RCHI T EC T URE OCTOBER 2016 commercialarchitecturemagazine.com http://www.commercialarchitecturemagazine.com

Table of Contents for the Digital Edition of Commercial Architecture October 2016