Photo gallery

The median divider separates the green roof system (left) and reference roof system. The weather station is located at the median divider.

Photo courtesy of the National Research Council Canada, Ottawa.

A green roof system was built on the Field Roofing Facility at the National Research Council Canada's campus in Ottawa. The wildflowers growing on the green roof system are native to Ontario or adapted to its climate.

Photo courtesy of the National Research Council Canada, Ottawa.

A retrofit metal roof system must have a framing system that allows metal roof panels to span across and above an existing roof system.

Photo courtesy of Architectural Metal Systems, Eufaula, Ala., and Metalcrafts Inc., Savannah, Ga.

A retrofit metal roof system must have a framing system that allows metal roof panels to span across and above an existing roof system.

Photo courtesy of Architectural Metal Systems, Eufaula, Ala., and Metalcrafts Inc., Savannah, Ga.

Figure 1: Base runners allow weight loads to be transferred across an existing roof surface.

Figure courtesy of Architectural Metal Systems, Eufaula, Ala., and Metalcrafts Inc., Savannah, Ga.

Figure 2: Rafter beams are installed at the top of posts connecting vertical posts to each other.

Figure courtesy of Architectural Metal Systems, Eufaula, Ala., and Metalcrafts Inc., Savannah, Ga.

Figure 3: Base clips also are used when installing retrofit metal roof systems.

Figure courtesy of Architectural Metal Systems, Eufaula, Ala., and Metalcrafts Inc., Savannah, Ga.

The Robert C. Cooley Middle School, Roseville, Calif., features cone-shaped turret, tapered metal panel and radius roof systems.

Photo courtesy of Kodiak Roofing and Waterproofing Co., Loomis, Calif.

The middle school was designed to reflect the city's history of being the largest railroad switching station in the West.

Photo courtesy of Kodiak Roofing and Waterproofing Co., Loomis, Calif.