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Denver Green Roofing Initiative and the Progression of Energy Efficient Roofing Systems

10/01/2023 2:20 PM | Anonymous member (Administrator)

By Joshua Flanagan, Blue Frog Roofing

With the continued growth and modernization of urban areas comes the human response to energy efficiency and health. Surprisingly, roofing systems can play a large factor in this response. Energy efficiency in regard to roofing is not a new idea; however, it only truly began to gain traction in the United States in the early 2000s when California changed their energy code to use cool roofing for commercial buildings. A cool roofing system is typically when a lighter color roof is installed in areas of high heat to reflect sunlight thus reducing energy costs. Energy efficient roofing has since taken further steps with solar panels and green roofing systems. 

The City of Denver passed an initiative in January of 2018 that originally required all new commercial buildings over 25,000 square feet to install a green roof. Green roofs, also known as vegetative roofs or living roofs, by definition are “ballasted roofs consisting of a waterproofing membrane, growing medium (soil) and vegetation (plants) overlying a traditional roof” (U.S GSA). Denver and its voters cheered as this initiative passed, but when it came time to discuss implementation, “it wasn’t looking feasible,” wrote Alicita Rodriguez in the CU Denver News. Rodriquez received some insight from Austin Troy, PhD, chair of urban and regional planning department at CU Denver’s College of Architecture and Planning on why it wasn’t looking feasible. Troy explained how green roofs are extremely expensive because of the structural support needed for the soil as well as the very high irrigation and drainage costs. Troy adds that if you force everyone to build a green roof, then investors are forced to pay a lot of money for something that may not get much use and potentially forgo low-cost green landscaping to save money. It’s important to consider that adding vegetation around buildings and using energy-saving materials can be more cost effective than green roofs while still being environmentally effective.

After half a year, and nine meetings, the Green Roofs Review Task Force changed the initiative to the Green Building Ordinance, effective on Nov. 2, 2018. So, instead of this one size fits all approach, the ordinance changed, permitting “new buildings over 25,000 feet to choose from a series of nine green-energy options in these areas: green roofs/green space, solar/renewable energy, energy efficiency, green building certifications (third-party programs), payment to the Green Building Fund, and the Energy Program (for roof replacement)”(Rodriquez). This gives developers, investors, and contractors a wider range of options while still participating in the modernization of energy efficiency. The following year construction results were a wide range of all nine options, with the most popular being cool roofs only, enrolling in the energy program, and on-site green spaces. Green roofs are still being proposed in Denver, but now a more selective plan can be addressed for those who choose that system. 

There are quite a few benefits to these energy efficient roofing systems. Cool roofs and green spaces are known to reduce the Urban heat island with cool roofing systems also saving around 10 to 15 percent in energy costs. Green spaces/roofs are also known to help with stormwater run-off management. Solar panels can reduce operating costs and attract tenants. Cool roofs are probably the most popular of these options listed since it is a simple and less expensive option than the others with choosing the right roof material and color. “Cool roofs achieve the greatest cooling savings in hot climates but can increase energy costs in colder climates if the annual heating penalty exceeds the annual cooling savings” ( In Denver, we typically have more warming days than cooling days, so installing a cool roof can reflect 60 to 90 percent of sunlight. Common materials for low slope (flat) roofs are TPO (thermoplastic polyolefin) which is white in color, PVC (polyvinyl chloride) which can be made with most colors, and light-colored metal roofing (standing seam or exposed fastener metal). However, in parts of the mountains at higher elevations with more cooling days, a cool roof system could be black EPDM roofing materials or dark colored metal roofing systems to retain more heat inside the building. For steep sloped buildings, any lighter colored materials including asphalt shingles can make a big difference in energy efficiency. Metal roofing types including Stone Coated Steel are also known to further energy efficiency. Synthetic materials like Brava or Di Vinci can achieve this as well. There are many other roofing materials, but these are some of the most popular. 

Blue Frog Roofing is a premium Roofing company servicing all of Colorado and Southern Wyoming taking an educational, consultative, and preventative maintenance approach. We specialize in Multifamily and commercial roofing and large loss while having a strong service/repair team.

(303) 585-0367

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