When building owners and architects require an attractive and affordable steep slope metal roof covering for a commercial building project, chances are that more and more of them will choose a metal roof.
Steep slope metal roofs, often defined as roofs with pitches of 3:12 or greater, have long been favored by environmentally sensitive building owners and architects who appreciate the roof's aesthetic appeal, long service life, low maintenance requirements, light weight and resistance to wind.
Steep slope metal roofs, for example, can enhance the appearance of virtually any building thanks, in large measure, to their receptivity to various coatings and their ability to be formed into a wide variety of shapes.
Because steep slope metal roofs accelerate the rate of water run-off, they also reduce the likelihood of a build-up of debris, mold and mildew. At the same time, they are less likely to experience staining from acid rain or UV degradation than non-metal steep slope systems. The durability and reliability of steep slope metal systems have led metal roof manufacturers to typically warranty their products for 20 to 40 years.
The environmental aspects of metal roofs have also prompted building owners and architects to take notice. For example, the use of steep slope metal roofs can contribute to LEED credits, which are awarded to buildings that use high recycled content and other "green" construction materials. A typical steep slope metal roof contains at least 25% recycled content, and at the end of its long, useful life is 100% recyclable.
In addition, "cool metal roofing" can significantly reduce a building's long-term energy use. Through the application of heat deflecting metal coatings, energy costs can be reduced up to 40% of more, according to a study conducted by Oak Ridge National Laboratory.
Steep slope metal roof systems typically weigh from 40 to 135 pounds per 100 square feet, making them among the lightest metal roofing products. A lightweight system places fewer demands on a building's structural support system, an important consideration, especially when choosing a sustainable roof material for buildings located in earthquake-prone areas.
Metal roof systems, with their interlocking or active fastening systems, are also excellent options for steep roof applications in areas subject to high winds. Metal roof systems are designed to meet the requirements of ASTM E1592, UL 580, UL 1897 and other severe wind and uplift tests.
Steep slope metal roofing products come in a variety of metal types, including steel, aluminum, copper and zinc, as well as many colors, textures and profiles. To ensure longer life, almost all metal roof products are protected from the elements by high-performance, highly durable coatings. Natural metal roof panels such as those made from zinc and copper are often left unfinished because of the protective patina that naturally occurs.
Steep slope metal roofs fall into two general categories — structural and architectural.
Steep slope structural roofs are generally applied over open framing, but they can be installed just as well over a solid deck.
Structural systems come in various styles, including vertical standing seam systems that are fastened to underlying purlins with hidden clips or fastening flanges. Also available are corrugated or tile facsimile metal roofs that are attached with exposed fasteners directly through the metal roofing panels. These products overlap or interlock on their side and end laps for a watertight fit.
Architectural steep slope metal roofs, unlike structural systems, always require a solid substrate beneath them â€“ typically plywood, oriented strand board, concrete or a metal roof deck. Architectural metal roof panels also come in a variety of styles, including standing seam, corrugated and tile profiles, as well as a variety of horizontal metal panels. Most architectural metal roofs are coated with a paint finish for added aesthetics.
Whether building owners or architects choose a structural or architectural steep slope metal system, they can be assured that they will obtain an environmentally sustainable product that will deliver exceptional performance and curb appeal along with an attractive return on investment.