The energy crisis of the 1970’s drove the roofing industry to create new products to meet revised efficiency guidelines. It was this period of innovation that saw the invention of modified bitumen roofing alternatives. We are seeing a similar trend now. Roofing manufacturers, power companies, government agencies, and environmental organizations are collaborating on new ways to conserve energy.
Perhaps the most creative of these are vegetative roofing and photovoltaic technologies. However, without government intervention by way of incentives, these are not likely to see a large market share for at least a decade. We are seeing some municipalities pushing for vegetative systems since they are energy efficient as well as reduce water runoff to sewer systems. For the most part, these will still remain “on the edge” technologies. Far more likely to see rapid adoption are cool roofing technologies.
Of concern especially in warmer climates like Oklahoma in the summer is Peak Energy Demand. PED is defined by the Environmental Protection Agency as “the maximum electricity used to meet the cooling load of a building or buildings in a given area.” The focus is to avoid the rolling energy blackouts that many areas have seen in recent years. On a hot afternoon in July, with cooling demand at it’s highest level, it is critical to have enough power to satisfy demand.
Today’s commercial roofing client is concerned with reflectivity and emissivity. The science behind these two terms is quite simple. Any roof system is exposed to radiation produced by the sun. This radiation is absorbed or reflected based primarily on the color of the roof system. A white roof reflects more sunlight than a dark roof. We need to remember that the light coming from the sun is both visible and infrared radiation (or heat.) The process associated with absorbing or reflecting heat is called emissivity.
Roof systems with a high emissivity reflect a large portion of the infrared radiation. As the surface of the roof heats up, due to absorbed visible and infrared light, the remainder of the roof system heats up as well. While insulation layers in the roof system can help reduce the amount of heat that passes to the building below, the use of cool, reflective products on the surface help to further reduce the surface temperature. This reduces the potential elevation of the building temperature. There is a direct relationship between reducing PED and increasing the reflectivity and emissivity of the surface roofing product.
Another important factor for building owners to consider is cost. While the vegetative or photovoltaic solutions are interesting, their cost is still prohibitive for most owners. Reflective technologies are now found in all product categories: coatings, mineral surfacing, single-ply thermoplastic membranes, metal roofing, modified bitumen membranes, and others.
Here at Terrell’s we continue to study emerging trends in commercial roofing products, while helping our clients determine the most complete and cost efficient solution to their commercial building roof needs. A commercial roof is a significant investment, let us help you get all the data you need to make the best decision.