Cool Roofs offer energy savings, durability and temparture control in certain types of climates. Of all the choices that must be made for a new construction project, the selection of a roof is one of the most critical. The type of roof employed for a new or remodeled structure influences maintenance costs, aesthetics, and the lifespan of the building.
There are a variety of roofing options for steel buildings that emphasize value, durability, and energy efficiency, including an innovation known as a “cool” roof. To be designated a cool roof, a roof must meet certain standards for its ability to reflect and emit heat.
At Capital Steel Industries, we offer a range of roofing options to meet your steel building requirements, and our roofs are easily adaptable to cool-roof technology. Before we discuss the benefits of a cool roof, it’s important to review some basic information about roofing choices.
The first choice that must be made involves the basic material. The two most common roofing materials are wood or steel. Steel has a number of advantages over wood, as it is stronger, fire-resistant, and not susceptible to certain issues that are prevalent with the use of wood, including mold, decay, warping, and cracking. Wood also absorbs heat, while steel reflects it, giving steel a natural ability to conserve energy. Overall, steel is a superior construction material. For the purposes of this article, we will assume the choice to utilize steel has already been made.
Once the material has been chosen, the type of steel roof and its design must be considered. The industry standards for steel roofs are screw-down roofs or standing-seam roofs. Screw-down roofs utilize flat or corrugated overlapping seams and exterior fasteners, while standing-seam roofs use elevated seams and concealed fasteners.
At Capital Steel we offer screw-down and standing-seam roofs that meet or exceed local building codes, and a 50-year structural warranty. We enhance the strength of our roofs by using thick, heavy-duty 26-gauge steel with a yield rating of 80,000 psi. In contrast, some competitors offer roofing that is constructed of less durable 29-gauge and may have psi ratings of 50,000 or less.
The majority of our clients request screw-down roofs for reliable performance and maximum value, while some clients prefer standing-steam roofs for aesthetic reasons or enhanced drainage capability. Either type is an excellent choice, as both designs provide the strength and energy efficiency that steel is noted for.
Regardless of whether you choose a screw-down or standing-seam roof for your building project, you’ll be selecting a roofing system that is energy efficient and has the potential to realize considerable savings in heating and cooling costs over the long term.
Along with strength, energy efficiency is a major selling point for steel as a building material and a roofing material. The use of steel is, in and of itself, an environmentally friendly choice with no further enhancements needed. However, today’s heightened focus on environmental issues may prompt the desire to add additional protective measures.
When it comes to roofing options, there are a variety of ways to further enhance the natural energy efficiency of your steel building. While a certified cool roof is an excellent conservation tool, the cost may be prohibitive. There are a multitude of options that fall on the continuum of green building practices, with choices available to fit every construction budget and situation.
The continuum begins with the selection of a steel screw-down or standing seam roof. As noted previously, steel is a reflective material that naturally lends itself to energy efficiency. During cooler months steel retains the heat generated within the structure and directs it back into the interior. During warmer months it deflects the sun’s rays away from the building, reducing the amount of heat that is absorbed. No matter the season, a steel roof promotes energy efficiency and provides a comfortable interior environment.
There are other choices that can be made for your steel building that move it farther along the energy continuum. These include interior insulation, exterior spray foam coatings, the color of the roof, its pitch, and the addition of energy-saving devices such as solar panels and water heaters.
Insulation can greatly enhance the energy efficiency of your steel building. According to the Department of Energy, the leakage of air is one of the main causes of wasted energy in any type of structure, and the use of insulation is recommended as an energy-conservation measure.
Insulation is assigned an R-value based on its ability to resist the flow of heat, with higher R-values indicating superior levels of protection. The recommended R-values vary depending on the local climate and the placement of the insulation within the structure. However, for roofing considerations, an R-30 value is highly recommended. Your Capital Steel dealer is knowledgeable about local conditions and insulation requirements, and will be happy to answer any questions you may have regarding the insulation of your steel building project.
Spray foam is liquid polyurethane that forms a seamless, protective roofing system. It can be sprayed onto a subroof or an existing roof, and it adds an additional layer of insulation. It is used most commonly on flat roofs, where appearance is not an important consideration. The extra insulation provided results in reduced energy consumption and lower utility bills.
The roof’s color plays an important role in its energy profile. Lighter colors are more reflective of the sun’s heat, and are therefore more energy efficient than darker shades. According to the EPA, a bare metal roof with no special coating or treatment has a reflectance rating of .50, which is ten times greater than the rating for a black roof.
Some exciting innovations are occurring with paint pigments. Capitalizing on military technology, the newly developed highly reflective pigments have the ability to reflect the infrared portion of the light spectrum. These Hi-R pigments, which are available in coatings sold under the brand names of Kynar and Hylar, give darker colors increased reflectance and make them a viable design option for eco-conscious builders.
The pitch, or slope, of a roof is another important factor in the design of a steel building. Roof pitch is defined as the number of inches the roof rises vertically for every 12 inches it extends horizontally. For example, a roof that rises 4 inches for every foot of horizontal measurement has a 4:12 pitch.
The slope of the roof has an impact on its energy efficiency. A flatter roof, which has little or no slope to it, has a far greater surface area exposed to the sun’s rays. A roof with a steeper pitch or slope has less exposure, and will absorb less heat. In terms of reflecting the sun’s heat, a steep roof is preferable to a flat roof. A steep roof also has a superior ability to repel water, and a higher level of aesthetic appeal.
However, the movement of air within the building also needs to be considered. A steeper roof creates a greater volume of air space overhead, which means more energy must be expended to circulate the air and maintain a comfortable temperature.
At Capital Steel, we have the ability to design a wide range of building plans that balance energy efficiency and aesthetic considerations.
Energy-efficient windows and doors have long been recognized as significant contributors in the effort to conserve resources and use energy wisely. Solar panels and solar water heaters are now gaining in popularity, and through 2008 such devices may qualify for federal tax credits and deductions. http://www.energystar.gov/index.cfm?c=products.pr_tax_credits)
The strength of Capital Steel’s 26-gauge steel makes our roofs an excellent support base for solar accessories. Be sure to discuss your plans for solar devices with your Capital Steel dealer, to ensure that the design of your steel building meets local building codes.
As you consider the design of your new steel building or remodeling project, keep in mind that energy-efficient devices may pay for themselves over the long term through lower energy bills, and some states offer rebates for commercial buildings and residential structures that meet energy standards. (http://www.coolroofs.org/codes_and_programs.html) There are also federal tax deductions available for commercial buildings that meet established standards for energy savings and efficiency. (http://www.energystar.gov/index.cfm?c=products.pr_tax_credits)
Roofs that are certified as cool roofs have an increased ability to protect the environment through lower energy usage. According to the EPA, a cool roof has the potential to lower air-conditioning costs by 20 to 70 percent, depending on the roof’s design.
Roofing options are measured based on their reflectance (the ability to reflect the sun’s rays away from the structure) and emittance (the ability to release stored heat). Reflectance is the most important measurement, with ratings established on a scale from 0 to 1. The Department of Energy’s scale defines reflectance ratings of .10 or less as low, .50 to .79 as medium, and .80 or above as high. A flat black roof has a rating of .05, while a white roof has a rating of .80.
Cool roof certification standards vary from state to state, but the federal Environmental Protection Agency requires a new low-slope roof to have a reflectance rating of 0.65 and a new steep-slope roof to have a rating of 0.25 to be labeled Energy Star-compliant. The U.S. Green Building Council’s LEED program uses SRI ratings, which are a combination of reflectance and emittance scores. The LEED program requires an SRI rating of 78 for low-sloped roofs and 29 for steep-sloped roofs. Reflectance and SRI ratings should be readily available from the roof’s manufacturer.
Capital Steel offers steel building roofs in a range of designer colors, including the naturally reflective shades of Polar White, Snow White, Almond, Light Stone, Ash Gray and Saddle Tan. We also offer Pacific Blue, Hawaiian Blue, Classic Green, Slate Gray, Charcoal Gray, Burnished Slate and Colonial Red. Any of these colors can be easily incorporated into the design of an energy-efficient structure. If you are interested in enhancing the energy efficiency of your roof or pursuing cool-roof certification, simply discuss the options with your local Capital Steel dealer.
At Capital Steel, we fully support the preservation of resources and our environment. Steel is 100 percent recyclable, and our advanced building system enlists precision cutting technology to eliminate waste and avoid contributing to landfills. Our steel building materials and roofing materials are friendly to the environment and help conserve energy. To learn more about the environmental benefits of steel, or for a free steel building quote or call Capital Steel Industries at 1-800-246-9640.