Cool Zone

In the commercial roofing industry, reflectivity and cool roofing has been the dominant discussion point for several years, and the Duro-Last® Cool Zone® roofing system has set the standard for single-ply roof reflectivity and the resulting energy savings.

Now, terms like sustainability, cool roofs, and cool roofing are receiving a lot of attention, and once again, Duro-Last is setting the bar.

But what does sustainability and cool roofing really mean for building owners, facility managers, contractors, architects, and other specifiers?

It means that the design, construction, maintenance, life-cycle impact, adaptive re-use, destruction, and recycling of roofing components must help meet the long-term environmental standards demanded by today’s high-performance buildings.


To be considered “sustainable,” a roofing system must meet the Five E’s of high-performance roofing: Energy, Environment, Endurance, Economics, and Engineering. In each of these areas, the Duro-Last Cool Zone roofing system leads the commercial roofing industry.

A high-performance roof can be a powerful asset in reducing energy consumption by becoming an energy efficient roof – a Cool Roof. When used with appropriate insulation on low-sloped or flat roofs, a high-emissivity Duro-Last Cool Zone reflective roofing system can:

  • Reduce building energy consumption by up to 40 percent
  • Improve insulation performance to reduce winter heat loss and summer heat gain
  • Preserve the efficiency of rooftop air conditioning
  • Potentially reduce HVAC capacity requirements
  • Decrease the effects of Urban Heat Islands and related urban air pollution
A popular definition for sustainable roofing was developed during a workshop held at the Oak Ridge National Laboratory (ORNL) in 1996: A roof system that is designed, constructed, maintained, rehabilitated and demolished with an emphasis throughout its life cycle on using natural resources efficiently and preserving the global environment.

The Duro-Last Cool Zone roofing system can minimize environmental impact in several ways:

  • Duro-Last is a member of the U.S. Green Building Council ( The USGBC’s Leadership in Energy and Environmental Design (LEED) voluntary rating system is an increasingly popular means for helping building owners determine environmental performance of building components. The Cool Zone system can help in obtaining credits toward LEED and LEED-EB certification.
  • Our closed-loop manufacturing process recycles production scrap, benefiting waste reduction
  • Because the roofing system is lightweight, less fuel is needed to transport it to the job site than other systems
  • The Duro-Last Cool Zone system can often be installed over an existing roof, reducing waste, landfill space and disposal costs. Oak Ridge National Laboratories (ORNL – recently estimated that 9-10 million tons of non-recyclable roofing waste is sent to U.S. landfills every year
  • Duro-Last offers a “Recycle Your Roof” program, which can reduce disposal costs of existing PVC roof membrane tear-offs when a tear-off is required.
  • At the end of its life as a roof, the Duro-Last Cool Zone roofing system can be recycled into other useful products such as specialty flooring (as demonstrated by Oscoda Plastics Inc., Duro-Last’s sister company) and other products.
In terms of High-Performance Roofing, endurance is the ultimate reflection of the performance of every roofing component in terms of reliability, water absorption, wind and fire resistance, maintenance, and repair. No matter how “cool” or “green” a roof is, it still has to protect the building – for years – in all types of weather – a reality that is sometimes neglected in sustainability discussions.

If you’re looking for a roof that will last, consider our track record. More than one billion square feet of Duro-Last membrane have been installed throughout the U.S. since the late 1970s – and many of these roofs are still in service. What makes a Duro-Last Cool Zone roofing system so durable? Each roof we make is:

  • Resistant to water, fire, chemicals, grease, and punctures
  • Able to stand up to all types of weather – including high winds and extremes of hot and cold
  • Virtually maintenance free, unlike other roof materials that may require regular patching and repairs
  • Reinforced with a high-density weft-insertion scrim for exceptional strength and durability
  • Confidently backed by the industry’s best warranties. Duro-Last protects commercial and industrial building owners with either a 15-year full warranty or a 20-year prorated warranty. Both are transferable, and both provide maximum protection. Our standard warranty includes coverage for consequential damages that result from defects in the Duro-Last material and/or installation.

Not only does a Duro-Last Cool Zone roof perform well over the years, it can actually help extend the useful life of other building components. By keeping moisture out while reflecting ultraviolet (UV) and infrared (IR) radiation, it can help to protect underlying insulation and the roofing substrate from deterioration.

While some types of roofing may have lower initial costs, the true costs of a roofing system are measured over its total life cycle. These include maintenance and repair costs, energy savings, and tear-off and disposal costs. Clearly, economics is a very important criterion for building owners, and High-Performance Roofing systems must be economical if they are to become viable, real-world options.

A Duro-Last Cool Zone roofing system delivers excellent life-cycle economics. Key benefits include:

  • Reduced installation costs through custom factory prefabrication
  • Low maintenance and repair costs
  • Protection from interior damage costs through leak-proof performance
  • Elimination of extended warranty costs
  • Savings incurred through reduced energy consumption, and related rebates or incentives

In 2004 – before the most recent energy price increases – a 20-year comparison was prepared with the help of independent Midwest roofing contractors. The objective was to compare the life-cycle costs of a High-Performance Roofing system – in this case, a prefabricated white PVC single-ply – with popular black EPDM and BUR systems for a fully-warranted, 50,000 square-foot re-roof in the Midwest. This hypothetical comparison clearly demonstrates the impact that an energy-efficient, High-Performance Roof can have over time.

Smart, coordinated engineering and design is not only the essential enabler for the other “E’s” of High-Performance Roofing, it is the key to what the Department of Energy calls “whole-building design”, which integrates all the subsystems and parts of the building to work more effectively together from “cradle to cradle”.

Stringent measures help ensure that the highest level of quality control is implemented throughout the manufacturing process. From raw material selection to job site delivery, at least 14 different Duro-Last personnel inspect, evaluate, and qualify the materials and processes that are used to produce the Cool Zone roofing system.

Every Cool Zone roof is engineered as a completely integrated system, prefabricated to the exact measurements of each building. Not only is up to 85 percent of membrane seaming completed in a factory-controlled environment, roof stacks, flashings, and edge details are also completed at the factory and shipped to the building site as part of the complete roofing system. The few remaining seams are then hot-air welded on-site by an approved contractor and inspected by a Duro-Last technical representative before a warranty is issued.

Thanks to the precision fabrication of the Cool Zone roofing system, installation is much faster and less disruptive than for a typical “roll-goods” roof. The installation process is quiet, with no noxious fumes or flames, so building occupants can continue with their regular routines.


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