Construction Concerns: Metal Roofs

By Gregory Havel

Metal roofs of galvanized steel were once limited to industrial and agricultural buildings and to engineered steel buildings with painted surfaces. Metal roofs were used where low cost and low maintenance were needed, and appearance was not a design factor. These roofs could have longer life than asphalt shingle or roll roofing, with less cost and less maintenance. Copper standing-seam roofs (photo 1) were also used where appearance and low maintenance were required.

(1) Photos by author.

In the 1990s, new metal roofing materials were developed at the same time that economical metal stamping methods and durable colored metal finishes were developed, using decades of experience with engineered steel buildings.

Today, metal roofs are installed as original equipment (photo 2) and as re-roof jobs (photo 3) on any type of structure, including businesses and single-family residences. These can be of steel or aluminum and in a variety of colors and a variety of interlocking panels that imitate the appearance of wood shakes, tiles, and slates. These roofs are also installed with traditional standing seams. Copper is also still used on some buildings.

(2)

(3)

Although the initial cost may be competitive with other roofing materials, metal roofs are attractive because of their long life and low maintenance. Some metal roofing materials are advertised as having two or three times the life of traditional materials, with less maintenance cost.

Metal roofs can complicate the size-up of buildings for firefighters since the builldings can look like they are made of materials which they are not. On strip malls, minimarts, and fast food restaurants, these roofs can be configured to conceal flat roof decks that support air-conditioning and refrigeration equipment. They can also complicate vertical ventilation. No matter the material or finish, they are slippery when dry, and even more so when wet or snow covered. A roof ladder is essential for firefighter safety, even on a low-sloped metal roof when ventilating. Firefighters may prefer to work from an aerial ladder or other aerial device to avoid having to step on the roof and risk falling.

Improper size-up can also result in delayed vertical ventilation because of the selection of the wrong tools or saws with blades that are not suitable for cutting both metal and wood. As a replacement, metal roofs can be installed over the existing roof deck of plywood, oriented strand board (OSB), or tongue-and-groove boards supported by rafters or trusses. In new construction, metal roofs are installed over roof decks of plywood or OSB supported by rafters, I-joists, or trusses.

As our response areas begin to include sloped metal roofs, we should plan to work only from aerial apparatus or roof ladders and to equip our power saws with blades that will effectively cut most types of roofing materials.

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Gregory Havel is a member of the Town of Burlington (WI) Fire Department; retired deputy chief and training officer; and a 35-year veteran of the fire service. He is a Wisconsin-certified fire instructor II, fire officer II, and fire inspector; an adjunct instructor in fire service programs at Gateway Technical College; and safety director for Scherrer Construction Co., Inc. Havel has a bachelor’s degree from St. Norbert College; has more than 35 years of experience in facilities management and building construction; and has presented classes at FDIC.

 

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