National Coatings - Reflective Roof Coating

National Coatings specializes in manufacturing many highly reflective roof coating products. The premium, high quality ingredients that are combined into making our reflective roof coatings allow for high performance and code compliant ways to reduce expenses related to global climate change; such as high energy costs and expensive roof maintenance while extending the roof life of your building.

National Coatings advanced reflective roof coating technology allows you to reflect a minimum of 72 percent of the suns energy from your building. We have many different reflective roof coating products that reflect damaging ultraviolet and infrared sunlight from 72 percent to 92 percent, the industry’s highest recorded reflectivity listed with the Cool Roof Rating Council(CRRC). Reflecting that amount of heat away from the building allows for cooler roof and building temperatures resulting in a reduction in air conditioning energy usage. All of our CRRC listed products are compliant with California Title 24 Energy codes. All of our reflective roof coatings have an advanced waterproofing technology that guards your roof from harmful sun rays thereby extending the life of the roof.

Related Articles to Reflective Roof Coating

Figure 1: This shot of the existing BUR and aggregate over an 80-year-old office building and manufacturing facility shows the state of the roof before it was replaced.

Nowadays, more and more of the decision making involves considerations in addition to the quickest and most economical method of stopping the leak. Our industry is going green faster than ever before as the environmental impact of the process is more universally understood. And there are legitimate green considerations that all decisions should take into account today. Can I install a roof system or product that will help to reduce my energy costs? Can I do my part by not contributing to more unneeded landfill? Can I help to reduce the urban heat island effect?

In addition to answering these questions, most building professionals will want to defer the cost of complete roof replacement if possible. This is only an option if the existing roof system has service life remaining. A thorough inspection by an industry professional can accurately make this assessment.

SPF Case Study

Figure 2: This photo shows the roof after spray polyurethane foam was applied and covered with a bright white acrylic coating to protect the SPF from ultraviolet degradation.

Consider the project illustrated in the before-and-after photos labeled Figures 1 and 2. The building had an older gravel built-up roof (BUR) over an office and manufacturing facility. The owner could not afford the downtime involved in a tear-off and roof replacement project. He was also seeking a way to increase the insulation capability of this almost 80-year-old building. The choice of a spray polyurethane foam roof covered with a bright white acrylic coating was an ideal solution.

After a thermal scan was performed to determine no extensive trapped moisture existed in the current roof system, the decision to proceed was made. As part of the prep process, all of the older aggregate was removed. The owner made use of the gravel to shore up his gravel parking area so the product removed from the roof never left the property. The older wood deck, still in good shape, was relieved of the weight of the aggregate as well.

Once the gravel was removed, the surface was primed completely to ensure maximum adhesion of the spray polyurethane foam to the substrate. Most primers available today will set up quickly to allow the SPF to be applied the same day on any primed section. A minimum of 1.5 inches of a 2.8 pounds per square foot roofing foam was installed over the field of the roof. Given the adequate positive slope of the roof, an acrylic coating proved to be the appropriate choice to protect the SPF from ultraviolet degradation. A base coat of gray preceded the bright white top coat. This entire project was completed with no roof tear-off or aggregate being hauled away to the area landfill and no interruption to the manufacturing process inside the facility. The newly installed finished system has eliminated all of the leaks and reduced the load on the roof. It is also lowering energy costs. And this new roof can be sustained through recoating at the 10-year anniversary of the original SPF installation. This owner is also conducting an ongoing energy audit to determine their actual payback period for this new roof investment.

Solutions For Metal Roofs

Figure 3. This 100,000-square-foot commercial warehouse building had several leaks in its metal roof. After the metal roof was thoroughly cleaned and all penetrations were sealed, a two-coat application of an acrylic elastomeric restored the roof to a leak-free state and lowered the surface temperature.

Metal roofs are also excellent candidates for a reflective coating system. The project featured in Figure 3 was a 100,000-square-foot commercial warehouse building with multiple tenants. Once the roof leaks became widespread, the owner was forced into coming up with a solution quickly or risk losing monthly rental revenue.

The decision to have an elastomeric, reflective coating installed proved to be the correct one for this owner. The roof was effectively prepared by thorough cleaning and sealing all penetrations, skylights and fasteners with an acrylic seam sealer. Only limited areas of rust were present, and therefore only spot priming was necessary. A two-coat application of an acrylic elastomeric not only restored the roof to a leak-free state, it also resulted in lowering the surface temperature as well. The tenants noticed a more comfortable environment in the non-climate controlled warehouse areas, as well as lower utility bills in the air conditioned office areas. Furthermore, the new white roof surface will greatly reduce the thermal shock (expansion and contraction of the metal during temperature changes) that occurred to the uncoated metal roof, ultimately extending the service life of the roof.

These two projects underscore the advantages of using reflective roof coatings in suitable applications. The roof coating industry today features state of art chemistry in product formulation and decades of field application experience. This combination has resulted in another revenue stream for roofing contractors while providing quality solutions that meet the needs of their clients. And, while the overall commercial roofing industry may see some challenges during the coming year, look for opportunities with reflective roof coatings to continue their growth.

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Highly reflective, field-applied roof coatings have demonstrated the ability to protect the roof surface from the ravages of weather and extend the roof’s performance life by reflecting ultraviolet (UV) light that starts the weathering process, reflecting infrared (IR) light that heats up the roof system and accelerates weathering, and shedding water, keeping it away from the original roof membrane so it cannot contribute to weathering.

Focus on energy
Increasingly, highly reflective white roof coatings also play a role in energy management of institutional land commercial buildings. They have been shown to reduce the temperature of a building’s black roof surface by 50-70 degrees. Lower roof-surface temperatures can reduce the need for cooling energy in a number of ways.

Lower surface temperatures mean roof insulation conducts less heat into the building, so the demand on chillers drops accordingly. They also translate into lower insulation temperature and increased effective R-value of the insulation.

Coatings can increase the efficiency of heating, ventilation, and air conditioning (HVAC) units mounted on the roof. And, cumulatively in mass in urban locations, they can contribute to lower air temperatures in the immediate vicinity of a building.

For example, rooftops on an entire city block in Philadelphia were coated with highly reflective white coatings, and the surrounding air temperature dropped about 1 degree during periods of summer heat.

Coating chemistry
Reflective roof coatings often are composed of a variety of synthetic elastomers — polymers with the ability to stretch and retain their original configuration — including acrylic, polyurethane, silicone, epoxy, and specialty polymers, such as fluoropolymers. Workers can apply these coatings over a range of common roof surfaces, including metal, asphalt, modified bitumen, plastic membranes such as polyvinylchloride (PVC) and thermoplastic polyolefin (TPO), and rubber materials, such as Hypalon.

When it comes to metal roof systems, an elastomeric reflective coating can reduce the summertime surface temperature from about 160 degrees or higher when uncoated to a surface temperature of about 110 degrees when coated. This 30 percent reduction is significant because it reduces the thermal shock.

Thermal shock is responsible for premature aging in metal roof systems, as it results in slight separations between panels and around vent pipes and other roof penetrations. If a metal roof system has exposed fasteners, these also will back out as a result of thermal shock. Typically, workers sealed these areas during detail work before installing an elastomeric coating. The coating seals areas of potential water penetration, reflect heat, cool the surface and extend the service life of the metal roof system.

Application issues
Managers must carefully consider several factors in applying highly reflective roof coatings to an existing roof, and applicators must follow good roofing practices. The roof should drain properly, wet insulation should be removed as part of the restoration process, weaknesses or limitations of the original roof system should be corrected, and the roof should be made watertight before the application of the reflective coating.

The coating should be part of a system that specifically supports compatibility and adhesion to the specific, original roof membrane in place. For example, one coating and system specification might be recommended for restoring an EPDM rubber membrane, and another might be designed for restoring a metal roof with a factory applied Kynar coating.

The long-term performance of a reflective coating also might depend on:
• the adhesion and compatibility of the coating with the roof substrate; field adhesion tests might be required.
• proper preparation and cleaning of the roof substrate surface before applying the coating.
• proper application of the coating.

Membrane restoration
For many years, manufacturers touted asphalt resaturants as replenishing the light fractions of asphalt into the bitumen roof membrane. These fractions in the original roof leech out of the membrane during natural weathering and cause the membrane to become brittle and less tolerant of movement associated with the roof.

From a practical perspective, chemical components that leech out during weathering and can be readily reinfused into the membrane via a maintenance coating probably will migrate out in a similar or shorter time frame. So from a practical standpoint, the ideal coating at least would prevent further loss of plasticizers and other key components from the membrane. But if the coating could block UV light, reduce water contact with the membrane and keep the membrane cooler, the roof would last longer.

Roof maintenance
One common question is whether all roofs are maintainable with coatings. They are, if the coating provides some performance property inherent in the roofing membrane that has deteriorated during normal weathering. For example, the coating on a metal roof might erode during weathering and can be recoated using the appropriate maintenance coating. Even uncoated metal subject to galvanic corrosion can be coated with a corrosion-inhibiting coating to prolong the roof life.

Built-up and modified bitumen roofs subject to surface degradation can be coated to provide additional protection in the form of high-film thickness over weathered and worn areas. If the coating has additional reflective properties, as in the case of aluminized or white coatings, the roof-membrane temperature can be reduced and the membrane’s life extended.

As single-ply roofs weather, causing chalking, crazing and checking, technicians also can maintain them with coatings. This coating would be specifically formulated to adhere to the membrane, tolerate the dynamics associated with the installation method — fully adhered or mechanically attached — and have excellent weathering characteristics equal or superior to the membrane chemistry.

A white or light-colored reflective coating applied to a black single-ply membrane will reduce the membrane temperature and, thus, reduce the thermally induced elongation and contraction of the membrane. This process also will reduce the stresses imposed on the mechanical attachments of the roof membrane.

Life-cycle costs
Life-cycle costing is an excellent vehicle for demonstrating that low first cost actually might be more expensive than a premium system when studied over the life of the roof.

Using coatings to prolong the roof has been shown to reduce a roof’s life-cycle costs. The longer a roof can remain in place without the need for costly tear off, disposal and disruption of occupants during re-roofing, the lower its long-term cost. Coating and subsequent recoating offer several additional benefits in terms of life-cycle cost.

First, periodic maintenance and recoating gives technicians an opportunity to inspect the roof and determine its condition. The technician then can make necessary repairs while the problems are still relatively small.

Second, coating and recoating — unlike reproofing - adds relatively little dead load to the structural demands of the roof. The typical elastomeric coating applied at 3 gallons per 100 square feet adds merely 24 pounds per 100 square feet when dry. So workers can apply many coats without concern for structural-load issues.

Reflective roof coatings are a useful and complimentary tool in maintaining and sustaining roofs. From the early use of asphalt cutback resaturants to today’s high-performance elastomeric coatings, which both protect and provide air conditioning energy savings through solar reflectivity, these coatings have demonstrated significant added value to building managers and owners.•

This special report is provided by the Reflective Roof Coatings Institute, www.reflectivecoatings.org.

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