Cool-Roofing Technology is a Breath of Fresh Air for Big Cities
Written By: Thomas Berry
In the pursuit of both protecting our environment and ourselves, the construction industry has looked at all aspects of the building process. Green Building is one of the fastest growing technologies to date, and with the rapid expansion of urban areas it is only natural that big cities are where most of the new processes are being implemented first. One such technology is the technique of cool-roofing.
Improving Upon the Past
Cool-roofing is a direct response to the poor design and unforeseen consequences of traditional roofing methods. Today, as many as 90% of US roofs are poorly designed, being built with dark, non-reflective, and heat absorbing materials. Especially noticeable in tightly-packed urban environments, traditional rooftop temperatures can soar far above that of surrounding areas. According to the Environmental Protection Agency (EPA), average city air temperatures can be up to 10°F warmer than nearby areas during the day and up to 22°F warmer at night! This phenomenon of large-scale heat attraction is known as the “Heat Island Effect” and poor roofing design is widely believed to be one of the leading contributors. Although the disparity in temperature is not typically so significant, even a few degrees can cause major issues. As temperatures rise, demand for air conditioning and forced cooling leads to larger energy consumption, increasing both costs to consumers and greenhouse gas emissions from a/c units and power plants. And, of course, higher temperatures lead to higher rates of heat stroke and other heat-related deaths. According to the National Oceanic and Atmospheric Administration, heat kills more people each year (on average) than tornadoes, hurricanes, floods, and lightning combined.
Assemble the Scientists!
To combat this dangerous trend in the roofing industry, research has been conducted on cool-roofing technology as early as the 1980s. The departments of energy for California and Tennessee found that white-coated and foam-coated rooftops, as well as roofs with vegetation growing on them experienced lower overall temperatures compared to roofs with traditional materials. This in turn led to lowered energy costs overall, although at the time the financial advantages were not significant enough to warrant an overhaul of the current roofing system. It wasn’t until 2001, when California was experiencing rolling blackouts due to energy demands, the issue was again put under investigation and cool roofing began to be utilized to lower energy requirements and consumption.
Understanding the Solar Reflective Index
How energy efficient a roofing system ranks is measured by a roof’s Solar Reflective Index (SRI) which is derived from two factors: Albedo (Solar Reflectivity) and Thermal Emittance (a roof’s ability to release absorbed heat). For label of a “cool roofing system” one must score an Albedo and Thermal Emittance of greater than 65% (most conventional roofing materials score a rating of only 5-15%). The benefits of such an investment as cool-roofing technology are numerous, and only compound the longer they are installed in your roofing system, saving not only the environment, but also your wallet. First, cool-roofing is better for the environment. Everyone benefits from the reduced temperatures from your building, both inside and outside. This is huge when multiplied by the countless buildings in metropolises like LA and New York. A direct outcome of this lowered temperature is lowered emissions from both personal A/C units and power plants around the globe. In addition to the effects on the environment, cool-roofing systems are extremely cost-effective; conveying an energy-use savings anywhere between 7 and 15% annually. Of course this differs based on the size of the building, but most systems have a payback period close to 6 years. This is assisted by government-funded utility rebates aimed directly at cool-roofing strategies (much like solar panel installation) and can help alleviate the initial cost of installation for wary consumers. Finally, cool-roof options require little in the way of maintenance and typically have longer lifespans than traditional roofing materials, thanks to updated designs and less heat-stress from sun exposure.
Consult with Roofing Experts
When deciding what type of roofing system is best for you, it’s best to have a licensed professional come out and survey your current roof so as to best determine option would work best for you. However, the ability to be informed cannot be stressed enough these days, and in the vein, we’ve decided to list a few of the most common types of cool-roofing systems. First, roofs are broken down into two different types: low-sloped or flat roofs and steep-sloped roofs. Low-sloped roofs are generally flat, with a slight incline for drainage purposes and are the best candidates for easy, affordable cool-roofing options. The first of these flat-roof options is coated roofing. These are literally roofs coated with a paint or pain-like finish, typically pure white or aluminum leafing flakes in an asphalt resin (for a more aesthetically pleasing finish), and help to greatly increase a building’s natural solar reflectivity. Foam roofs are topped with a foam insulation material, a type of “air-barrier”, and are time-tested, having been used for over 45 years as a reliable coo-roofing design.
Other Roofing Options
Finally there are single-ply membranes, which are prefabricated sheets that are individually applied to roofs that may need repair or refitting. Steep-sloped roofs require different techniques and materials due to their high-angles, high-visibility, and the types of materials already installed. Asphalt shingles have a relatively low SRI (maximum of 30%) but are often used residentially due to their ease of installation and cost-effective nature. However metal roofing has seen a resurgence in recent years, achieving a reflectivity rating of up to 70%. This method is known for its weather resistance, lightweight nature, and recyclability.
Cool-Roofing for Consumers
Whether it is huge companies in major metros or one home in a suburb, cool-roofing can have major benefits for both the consumer and the environment. With the state of the world today, we all must do our part to assist in the prolonging of this gorgeous planet of ours, and if we can save a little money in the process all the better.