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EXH AR024698: Memo — Roofing Options for Zinc Leaching Prevention

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Sea-Tac Airport
Third Runway
PCHB
Box 10

A April 2000 memo from engineering firm Parametrix, Inc. evaluates roofing options to prevent zinc leaching from galvanized steel roofs on two Port of Seattle warehouses at Sea-Tac Airport. The study compared paint systems (ranging from $21,000–$240,000 for both buildings) against synthetic coverings such as spray-on elastomers and single-ply membranes ($60,000–$330,000), finding that painting is cheaper but requires more frequent maintenance while synthetic coverings last longer but cost more upfront. The memo recommends that any chosen material be evaluated to ensure it does not release metals or other pollutants into stormwater runoff.

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Parametrix, Inc. memorandum dated April 5, 2000, from Michael Kluck and Stuart Currie to Paul Fendt, regarding roofing options to prevent zinc leaching from galvanized steel roofs of two warehouses owned by Port Of Seattle at Sea-Tac Airport (project number 555-2912-001). Research covered paint systems (acrylic, urethane, epoxy topcoats; $0.22–$2.50/sq ft; $21K–$240K total) and synthetic coverings (spray-on elastomer, single-ply membrane, polyurethane foam; $1.45–$3.50/sq ft; $60K–$330K total) for a combined roof area of 2.2 acres (95,835 sq ft). Sources contacted include Stevens Roofing Systems, Rainshield Roofing & Construction Co., Alpine Roofing, Fields Roof Service, Meyer Bros. Roofing, Stevens Roofing Systems, United Coatings, Somay Products, Inland Coatings, and Mainland Industrial Coatings. Exhibit AR024698, Third Runway EIS administrative record, PCHB.

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