Derek McCowan joined Simpson Gumpertz & Heger Inc. (SGH) in 2002. He has experience in designing, investigating, and rehabilitating building-envelope systems of contemporary and historic structures, as well as providing construction-phase services. He serves as a project manager for various large and complex projects, often working directly with owners, architects, construction managers and developer clients, as well as subcontractors, manufacturers, and other consultants. He specializes in glass-and-metal curtain wall systems, windows, roofing, plaza waterproofing, cladding, and skylights, and also has experience with foundation waterproofing and historic masonry structures. He writes and presents frequently on various building enclosure topics and has experience as a guest lecturer at various local universities.