Friday, July 29, 2011

Finding The ‘Right’ Roof Coating

When specifying a roof coating like those from Conklin to protect a roof membrane, you should how the coating measures up to a series of criteria. The coating:
  • must be compatible with the roofing materials to which it is applied
  • should be reflective and non-heat absorbing
  • should be fire-resistant and meet code requirements
  • should maintain its properties for at least five years without the need for re-coating
  • should have elastomeric properties to withstand normal roof movement
  • should be able to withstand normal foot traffic
  • should be able to resist water entry
Also, the existing roof must have adequate slope to prevent prolonged ponding on the coating. Perhaps most importantly, you should make sure that your goal in applying the roof coating is not to try making a bad roof good.

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Thursday, July 28, 2011

Aging and Asphalt-Based Roofing

Asphalt is a waterproofing agent and adhesive used in assembling multiple plies of organic or inorganic felts into one homogeneous roofing membrane, built-up roof systems. Manufacturers have used this type of construction successfully for decades, and it remains a common choice for roofing, with about 40 percent market share.

The asphalt used in built-up systems provides an excellent water barrier, but as with other materials, asphalt is highly subject to degradation from exposure, just as other materials are. Asphalt hardens progressively when exposed to roof temperatures. This occurs with all asphalt-based components, including cap sheets, saturated felts, and asphalt moppings.

Temperature changes cause the underlying asphalt to expand. Since the asphalt skin cannot stretch to accommodate the movement, random crack patterns appear to relieve the stress. Fresh asphalt is exposed below the broken skin.

Over time, the fresh asphalt within the cracks forms a new skin. The new skin layer will then eventually crack in the same line again, due to temperature changes, leaving a slightly deeper depression. This process repeats itself until the crack lines grow very deep and into the felts, allowing water infiltration.

A vital component of a successful built-up roof system is surfacing to protect the asphalt waterproofing component from the effects of exposure. The two most common methods of surfacing built-up roof membranes are a flood coat of aggregate embedded in asphalt or a mineral-surfaced cap sheet.

A cover of aggregate or minerals over the asphalt can minimize surface deterioration, but it has little effect on the hardening of the underlying asphalt. These types of surfaces simply do not keep the roof temperature from rising. In some cases, depending on the type of aggregate or color of minerals, they might absorb heat, further elevating temperatures.

So why are these two types of surfacing used most often? Because they provide a durable surface to withstand foot-traffic abuse, another important factor in roof longevity.

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Wednesday, July 27, 2011

How long should my roof last?

One of the most commonly asked questions in the roofing industry is “How long should the roof last?”

Although roofs fail prematurely due to unexpected external forces like including earthquakes, hail, hurricanes, tornados, and foot-traffic abuse, a primary reason for premature failure is regular and prolonged exposure to sun and wind.

All exterior-grade construction materials need to provide a means of fighting off sun and wind’s oxidizing effects, which result in aging. Roofing materials are in a league of their own in this regard, especially because their location makes them especially vulnerable. The roof is fully exposed to the sun’s rays and is elevated enough to allow wind to blow across it freely.

Exterior materials subjected to the deteriorating effects of aging and weather tend to diminish in performance. When materials are subjected to the roofing environment, deterioration from exposure and biological effects accelerates. The pressure on roofing materials to react or degrade is several times that of materials on the interior of the building.

In a growing number of institutional and commercial facilities, maintenance and engineering managers are specifying roof coatings like those from Conklin to protect roofing systems and, in turn, a facility’s interior operations and components. Many managers also are more closely investigating the role light-colored and reflective coatings play in holding down buildings’ cooling loads.

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Tuesday, July 26, 2011

Cool Roofing, UPS and Energy Secretary Steven Chu

If you’re not friends with Steven Chu on Facebook, you missed the Energy Secretary’s recent post about a white-topped UPS truck spotted in the nation’s capital. “An encouraging sight drove past my office last week—a UPS delivery truck sporting a white roof,” Chu wrote. “If UPS can set aside its trademark brown color scheme for the sake of a cooler cargo area, hopefully more businesses and consumers will begin to ask themselves: ‘What can white roofs do for you?’”

The answer to that question is that a white, or "cool" roof could potentially lower the surface temperature of your roof by up to 100°F. That's according to the California Energy Commission, which estimates that cool roofs can trim cooling costs by 20 percent on average in the state.

Cool roofs work by reflecting sunlight. Painting the roof white is one approach. Installing light-toned asphalt shingles or clay tiles with a reflective coating like those from Conklin can also redirect the sun’s energy. But cool roofs aren’t for everyone. Those in hot, sunny climate where air conditioning is used a lot will reap the biggest benefits. In other regions, a cool roof could end up increasing heating costs in the winter, so you should use the Department of Energy’s cool-roof calculator to see how much energy you’ll save.

Please also see the June 2011 article by Daniel DiClerico titled "Secretary Chu makes a friendly plea for cool roofs"

Tired of labor problems and low profit margins? Make more $$ spraying coatings with Conklin Roofing Systems! Patton Services | (309) 303-3128 | |

Monday, July 25, 2011

Benefits of Spray Foam Roof Systems

Spray foam roofing systems like those from Conklin provide many benefits to building owners. The two most prominent benefits are waterproofing/leak prevention and insulation value. Many additional benefits also exist such as superior compressive strength, lightweight, self-flashing, durable and long lasting.

Benefits of Spray Foam Roof Systems
  • Leak-free monolithic seal over your entire roof deck
  • Self-flashing
  • High insulation value
  • Rapid payback with energy savings
  • Strong adhesion and wind uplift resistance
  • Weather resistant
  • Lightweight and high strength
  • UL and FM approved systems

Sprayed Polyurethane Foam (SPF) is applied as a liquid using plural-component spray equipment to fill cracks and crevices. It then expands approximately 30 times its original liquid volume to form a hard, closed cell monolithic roof surface. The Polyurethane Foam dries within seconds after applied to the roof surface. Its expansion results in a weather tight roofing membrane that is fully adhered to the substrate. Because of polyurethane's lightweight it adds little additional weight to the structure and is often used in remedial applications.

Polyurethane Foam has a history of more than 35 years as a maintainable roofing medium. Polyurethane Foam adds excellent insulation value to the structure and utility bills can reflect the difference.

Once the SPF has been applied to the proper thickness and finish specifications, a protective layer of elastomeric coating or gravel is applied. This protective layer produces a durable weather resistant surface and that can be walked on for normal maintenance.

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Friday, July 22, 2011

Sustainable Roofing Options and Benefits

The impact that roofs have on energy is often overlooked, the impact of which can be significant. In winter, insufficient or damaged roof insulation allows heat to readily escape. In summer, heat gained through the roof increases not only the cooling load, but also the peak cooling load and — for buildings where the primary cooling system is electrically driven — the peak electrical demand. A flat or low-slope roof gives maximum exposure to the sun’s rays when the building’s cooling loads and costs are the highest.

Most flat and low-slope roof materials are black. These materials readily absorb solar energy, including the infrared portion of sunlight. Roof temperatures from noon to late afternoon are often 60 to 100 F higher than the ambient temperature. While some heat is radiated back to the atmosphere, much is conducted to the conditioned space below.

The impact the roof has on energy use depends on the climate, the orientation of the roof, the thickness and quality of insulation, the reflectivity of the roof’s surface, and how well the roof has been maintained.

Good roof maintenance should be a given. Leaks can allow water to penetrate the surface and saturate the insulation, destroying its thermal resistance. Wet insulation is almost the equivalent of no insulation. Wet insulation also accelerates the deterioration of other roofing components. It is essential for both energy efficiency and the integrity of the roof that roofs be properly maintained.

Sustainable Principles
Just as the growing use of life-cycle costing has changed how building system and component options are evaluated, the concept of sustainability is changing how facility executives look at roofing. Roofs designed with sustainability in mind go beyond first cost considerations and incorporate three other key factors: energy efficiency, the impact that the roof will have on the environment, and maintenance and renewal requirements over the life of the building.

One of the most attractive features of a sustainable approach is energy savings. By limiting the heat loss from the building during the heating season and by reducing the heat gain during the air-conditioning season, facility executives can reduce energy use and the environmental impact from energy use. Although a sustainable roof is more expensive than conventional roofs, energy savings recover those costs in a relatively short time, typically three to five years.

In addition to energy, the roof has another impact on the environment: waste products. All roofs have a finite service life. At the end of their service life, they have to be removed, replaced, recovered or renewed. A sustainable approach minimizes the waste produced from the roof over the life of the building by minimizing the number of times that the entire roof must be fully removed from the building. Instead of requiring removal and replacement, the roof is built from materials that can be recoated or renewed.

Reflective Surfaces
One of the most cost-effective steps to improve the energy efficiency of the roof is to apply a reflective coating like those from Conklin to the roof’s surface. An uncoated, black roof absorbs between 70 and 80 percent of the solar energy that strikes it. When a white or light-colored coating is applied, the solar absorption rate decreases to 20 to 30 percent. Surface temperatures will be only 15 to 20 F higher than the ambient temperature, far less than the 60 to 100 F temperature rise found with uncoated roofs.

On average, reflective coatings reduce heat gain through the roof by 50 percent for buildings in warm climates. Because most air conditioning systems are electrically driven, the reduction in cooling load cuts demand for electricity when the building is setting its peak use; peak reduction is typically between 10 and 15 percent.

Moreover, reflective coatings don’t boost winter heating costs significantly. One reason is that the heat loss through the roof is often small relative to the heat gain. For example, when it is 30 F outside and 70 F inside, the temperature differential is only 40 degrees — probably less because the sun will heat up even a reflective surface somewhat. During summer, the temperature differential is 70 F or more. The cost of air conditioning energy is also higher than the cost of heating energy. Finally, in winter, flat roofs in cold climates may well be covered with snow, which reflects solar energy.

Reflective roof coatings can also extend roof life. Ultraviolet light from the sun breaks down roofing materials, causing them to weaken or become brittle. Reflective roof coatings shield roofing materials from ultraviolet light.

High surface temperatures also accelerate the breakdown of roofing materials by increasing the rate at which chemical reactions take place, reactions that weaken materials or reduce their flexibility.

Uncoated roofs are also subjected to wide temperature swings during the day. Reflective coatings greatly decrease the thermal stress generated by temperature swings, which can lead to early component failures.

Reflective roofs can also help to reduce an environmental impact that all dark-surfaced roofs contribute to: urban heat islands. Urban heat islands occur when a concentration of dark surfaces, such as roofs and asphalt pavement, absorb enough solar radiation to elevate the surrounding temperature by several degrees. These higher local temperatures increase cooling loads and energy use.

Reflective coatings must be matched to the type of roof installed, as not all coatings are compatible with all roofing materials. Most coatings can be applied for less than $1 per square foot. While coatings are durable, they do wear and their reflectivity decreases with age. Most must be reapplied every 5 to 6 years to maintain reflectivity and protective properties.

When considering reflective coatings, look for one that carries the Energy Star® label. These products have been certified to reflect at least 65 percent of the solar radiation that strikes the roof, without reducing the quality or the performance of the roof. Some products that carry the certification have reflectivities as high as 85 percent.

Roof Insulation
Depending on the type of roof and the structure on which it is installed, a range of roofing insulation products can be used, including fiberboard, fiberglass, perlite, cellular glass, corkboard, polyurethane and polystyrene. Most come in flat boards ranging from 1 to 4 inches thick. Boards are available with a built-in taper of 1&Mac218;8 to 1&Mac218;4 inch per foot for roofs where the insulation is used to increase slope for roof drainage. Not all insulation types are compatible with all membranes.

The most obvious function of insulation is to limit heat transfer to or from the building interior through the roof. However, more insulation is not always better. While additional insulation may decrease the rate of heat transfer into or out of the building through the roof, it can also stress the roof membrane by increasing thermal shock. Thermal shock occurs when large and rapid swings in temperature cause the membrane to move relative to the roof’s deck. The thicker the roof insulation, the greater the potential for thermal shock. If the membrane moves relative to the roof deck, failed flashings, splits in the membrane seams and cracks around roof penetrations could occur. Therefore, it is essential that manufacturer’s guidelines be followed when determining type and thickness of roof insulation.

Green Roofs
One type of roof that, while not new, is receiving considerable attention is the so-called green roof, a system that includes vegetation as part of the roof. The vegetation is planted in a layer of dirt or an artificial growing medium as the top layer of the roofing system. The bottom layers consist of a conventional roof applied to the roof deck. Between the two layers is a drainage system to carry away excess water and a filter system to prevent the growing medium from entering and clogging the drainage system.

The green roof offers several advantages. The vegetation and growing medium shield the other roofing components from ultraviolet rays. The green roof also adds another layer of insulation between the building and the outside air. Solar heat gain is nearly eliminated. Evaporation of water from the growing medium and the loss of water from the leaves of the plants provides evaporative cooling for the building. Major temperature swings in the roofing membrane are practically eliminated. Like reflective roofs, green roofs help reduce the urban heat island effect.

The roofs can also help control storm-water runoff by temporarily storing and then slowly releasing rainwater. One concern with green roofs is the difficulty of finding leaks.

Before a green roof can be installed, the building’s roof structure must be studied to determine that it can carry the additional weight of the growing medium and retained water. Vegetation must be carefully selected based on the local climate, including range of temperatures, rainfall, wind conditions and sun exposure. It is very important to have someone with a good deal of experience with green roofs design the roof and oversee the installation.

What is the net economic effect of a sustainable approach to roofing? Facility executives have found that their cooling loads decrease, some by as much as 40 percent, without a significant increase in winter heating loads. By lowering the temperature of the roof’s surface, roofing materials have an extended service life. Reduced thermal stresses on components cuts maintenance requirements and extends the service life of the roof. The additional first cost of a sustainably designed roof is typically recovered in three to five years.

Please also see the August 2003 article by James Piper titled "Roofing, Energy and the Environment"

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Thursday, July 21, 2011

Before You Install A Built-Up Roof...

Maintenance and engineering managers have specified built-up roofing (BUR) systems on institutional and commercial facilities for years, seeking durability and flexibility. To ensure BUR systems deliver these and other benefits to their organizations, managers must ensure front-line technicians maintain them properly. A properly managed and coordinated quality-assurance inspection program during installation can help managers and inspectors identify and address common performance problems with BUR systems.

Inspectors first must understand the roofing system's drawings and specifications before installation. A pre-construction meeting that includes the architect, consultant, inspector, roofing contractor foreman, general contractor, sheet-metal contractor, and other interested parties enables those involved to discuss the project, its details, and last-minute questions.

This discussion also might cover expectations from the inspector, such as the distribution of daily and formal inspection reports— as well as any test-sample results— and identifying to whom the reports will go.

Experienced inspectors must understand they are responsible for making sure everyone involved is fully informed and the organization receives a proper return on its investment. For example, a contractor's failure to comply with approved plans and specifications is not acceptable, and the inspector needs to make the foreman and the maintenance manager aware of the issue.

A comprehensive roof inspection must cover the primary components of the installed system.
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Wednesday, July 20, 2011

Cool Roofs In Cool Climates

Even though cool roofing remains a hot industry trend, the science behind cool roofs - things like infrared emissivity and solar reflectance, isn’t exactly top on mind for facility executives researching roofing options.

To most people, cool roofing is a cut-and-dry issue: Roofing systems like those from Conklin that reflect the sun’s rays can save energy (and thus, money) in warm climates year-round and during hot summer months in more seasonal climates. Less clear and more controversial is whether cool roofing is beneficial in climates where, over the course of a year, heating energy loads dominate cooling. In other words, can cool roofs be advantageous in cold climates?

The answer to that question begins with a more complete picture of how a cool roof functions. “A cool roof is a roof that combines reflectivity and infrared emittance to keep the roof temperature cool,” says Andre Desjarlais, program manager for the Building Envelope research program at the U.S. Department of Energy’s Oak Ridge National Laboratory.
  • Reflectivity is a measure of the percentage of solar radiation that is reflected when it strikes the roof surface.
  • Infrared emittance, or emissivity, is a measure of the amount of remaining solar radiation that is released from the roof surface to the sky.

Solar radiation is made up of three forms of energy: about 5 percent ultraviolet, 45 percent visible light, and 50 percent infrared. When that energy strikes a roof, it is dealt with in several ways. For cool roofs, the largest portion is reflected, but energy is also emitted as infrared energy to the atmosphere. The energy that is absorbed and converted to heat is transferred through convection with the air directly above the surface, and the remaining heat is conducted into the building.

Most industry experts agree that reflectivity has a greater impact than emissivity on the energy performance of the roof during hot weather. If a majority of the initial solar radiation is reflected, then a smaller portion is left for infrared emittance. Many cool roofs have reflectivities of 75 to 80 percent, or 0.75 to 0.80, which means that only 20 to 25 percent of the sun’s energy is absorbed into the roof.

According to Lawrence Berkeley National Laboratory (LBNL), at an ambient temperature of 98 degrees, raising a roof’s reflectivity from 0.25 to 0.40 while keeping emissivity constant results in a surface temperature reduction of 13 degrees. A change in a roof’s emissivity from 0.75 to 0.90 while keeping reflectivity constant results in a surface temperature reduction of only 2 degrees.

The combination of high reflectivity, usually a result of light-colored or white surfaces, and high emissivity during hot summer months results in a surface temperature sometimes as much as 60 to 70 degrees cooler than a non-reflective roof. With less net heat energy to deal with, the air conditioning system doesn’t have to work as hard to keep the building at a comfortable temperature.

While the reflective and emissive properties of a roof are most important for its coolness, other factors such as insulation, roof orientation and roof pitch contribute to a building’s overall thermal efficiency. “Building owners should never agree to a roof based solely on the fact that it’s a white roof,” says Jared Blum, president of the Polyisocyanurate Manufacturers Association and a board member of the Solar Smart Roof Alliance.

Some of the long-term performance issues of roof selection should also be considered, including maintenance costs, such as power washing or recoating, that might be necessary to keep the roof performing as it did when it was initially installed. Another consideration is a roof’s long-term ability to match functionality with aesthetics.

But even if the roof is kept in mint condition, the question remains of whether the cool roof will be a thermal detriment in a heating-dominated climate.

“The ideal roof would be 100 percent reflective in the summer and 100 percent absorbent in the winter,” says Art Rosenfeld, California Energy Commissioner. Unfortunately, a roof can’t change its reflective and emissive properties, so the general energy efficiency of a cool roof must be assessed by comparing the energy saved during the hot summer months to the energy consumed, or the “heating penalty,” during the heating season.

Skeptics of the energy benefits of cool roofs postulate that in cold climates, such as Minneapolis or Chicago, where heating degree-days vastly outnumber cooling degree-days, the heating penalty would be severe enough to render a cool roof counterproductive.
Heating and cooling degree-days are measures of the number of degrees the average daily temperature falls below or above 65 degrees. For instance, if the average temperature for a 24-hour period is 23 degrees, that day chalks up 42 heating degree-days. The main purpose of heating and cooling degree-days is to serve as an index of heating and cooling energy loads over defined time periods. But they also help determine whether certain building strategies are appropriate for a particular geography.

This use was the impetus behind their inclusion as variables in the development of calculators that predict how much energy and, by extension, how much money per square foot would be saved with the use of cool roofs vs. non-reflective roofs in specific locations. The calculators, developed separately by the U.S. Environmental Protection Agency and the Department of Energy’s Oak Ridge National Laboratory, allow users to enter the thermal properties of the proposed roof, amount of insulation, cost of energy and efficiency of the building’s HVAC systems, among other things.

The calculators are not meant to be precise indicators of specific building performance. Rather, they help give a general indication of how certain roofing materials with specific thermal properties will perform in various parts of the country. In other words, they can help settle the argument, from strictly an energy usage and monetary perspective, whether cool roofs can be beneficial in cold climates. In many cases, even in the cold climates, the calculators still yield a yearly net savings for using cool roofs.

There are at least five reasons why the heating penalty in the winter time isn’t nearly as severe as it could be and why the summer cooling savings, to some degree, are able to counteract the winter heating penalty in cold climates:
  1. During the winter, the solar angle is lower so reflectivity and absorption aren’t as important. Reflectivity and absorption are more critical during the summer when the sun is higher in the sky and solar radiation is hitting the roof directly.
  2. The days during winter months are shorter so less total energy is hitting the roof to be absorbed or reflected over the same period of time as during the summer.
  3. The ratio of cloudy to sunny days increases during the winter, so again, not as much solar energy is striking the roof.
  4. Snow piled up on the roof during parts of the winter reflects the sun’s energy. Therefore, it doesn’t matter how reflective or absorbent the roof is.
  5. In many cases, resources cheaper than electricity, such as natural gas or oil, are used to heat buildings in the winter.

Still, in far northern climates like Chicago, the actual savings, strictly in terms of energy use, if any, might be fairly minor, says Desjarlais.

The debate doesn’t end there, though, as cool roofs in seasonal climates can be beneficial for other reasons. That’s because cool roofs can have more impact on energy costs than energy use. Cool roofs cut energy use during peak demand times during summer when rates are highest. What’s more, cool roofs can help reduce the demand charge that a facility pays all year on the basis of its greatest energy use. Additionally, some northern utility companies offer rebates and incentives for tactics like cool roofs that help facilities cut down on the peak demand load. The idea is to help ensure that there will be enough energy to go around, thus avoiding brownouts.

“The peak demand benefits of cool roofing are the same no matter how far north you march,” says Desjarlais.

“Why would utility companies offer incentives in cold climates if there wasn’t a benefit?” asks Scott Kriner, technical director of the Metal Construction Association and chairman of the Cool Metal Roofing Coalition.

“The only building that won’t benefit from a cool roof energy-wise is one that’s not air-conditioned,” says Hashem Akbari, staff scientist and group leader for Lawrence Berkeley National Laboratory’s Heat Island Group.

Akbari’s group also researches measures cities can adopt to mitigate the urban heat island effect, another area in which cool roofs are invaluable, even in seasonal climates. The urban heat island effect is a phenomenon wherein dark building materials, dark pavement and lack of vegetation create a 6 to 8 degree difference between downtown areas of major metropolitan cities and outlying suburban areas. The elevated temperature means that cities as a whole and buildings specifically consume more cooling energy. Additionally, as the air temperature increases, air quality decreases, putting people at further risk for smog-related health problems.

Because of the lower roof surface temperature on roofs with a high emissivity and high reflectivity, urban heat islands can be reduced with widespread use of cool roofs. This is true even in cities with seasonal climates. A study performed by Akbari and his team in Toronto shows that if heat-island-reducing measures, including cool roofs, were adopted widely, the city could save more than $10 million a year on energy costs.

On a national level, widespread adoption of cool roofs, independent of other mitigation measures, could save close to $750 million in energy costs in major urban areas, LBNL estimates.

“It’s a collective thing for building owners,” says Greg Crawford, executive director of the Cool Metal Roofing Coalition. “If several buildings begin installing reflective roofs, it will lower the temperature of the urban area and reduce the natural load on building systems.”

Please also see the March 2004 article by Greg Zimmerman titled "Do Cool Roofs Fit In Cool Climates?"

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Tuesday, July 19, 2011

Push for Cool Roofs Runs from Rebates to Mandates

As you know, a dark roof can add significantly to a building’s cooling load. The interest in lighter, more reflective roofs has been around for more than a decade, and the products like those from Conklin are increasingly more varied and claim ever-greater levels of reflectiveness. Incentives from government agencies and local utilities have sprung up in a half-dozen Sunbelt states, and research is continuing to provide more insight.

Approximately $40 billion is spent annually in the United States for cooling commercial buildings — one-sixth of the electricity consumed nationwide! Research has verified that various roof products like those from Conklin have greatly reduced air conditioning loads in buildings, cutting energy bills up to 50 percent, and shaving air-conditioning peak usage by 10 to 15 percent.

For example, a strip mall and single-story flat-roof commercial buildings in Florida with metal roofs experienced a 25 percent cut in cooling loads; school buildings tested were in the 10 percent range, says Craig Muccio, an end-use evaluation coordinator at Florida Power and Light (FPL), which operates in the state with the largest amount of cooling degree days in the nation.

A range of variables contributes to the amount of savings, according to FPL’s research, Muccio says. Four of the key factors are the air-conditioning system’s efficiency, the age of the roof, the level of insulation, and the configuration and orientation of the buildings.

Pacific Gas and Electric Co. (PGE) has been closely monitoring ongoing research and other cool-roof programs at the California Energy Commission (CEC) and the Lawrence Berkeley National Laboratory (LBNL), Livermore, Calif., a federal research center managed by the University of California, Berkeley. “Our objective recently has been to understand how well cool roofs work and under what conditions they save energy,”says Peter Turnbull, customer service program manager for the San Francisco utility.

In California, LBNL tested three cool-roof buildings in the state’s hot Central Valley region: two medical office buildings, measuring 30,000 and 50,000 square feet, and a large chain drug store outlet. The two medical buildings cut air conditioning loads by 18 and 13 percent, respectively, while the drug store’s load dropped by about 2 percent.

As part of a cool-roof initiative among a number of utilities in Southeastern states, FPL initiated some of the most concentrated roofing efforts. “We looked to see if there were technologies and applications that would help the overall load profiles for our customers,” says Jack Rows, an FPL energy efficiency manager. “Within Florida, we have been in it longer than any of the other utilities in the Southeast, so we’re a good baseline for looking at cool roofs.”

One of the assessments by LBNL estimates potential annual savings from cool roofs in about a dozen major metropolitan areas, and the locations in the Sunbelt, not surprisingly, offer the most potential savings, with Phoenix and Los Angeles leading the way; Dallas, Houston and Miami are next. Buildings in Philadelphia, Washington, D.C., and Chicago will see savings, but the potential is less than for their Sunbelt counterparts.

Ideal climates for potential cool-roof buildings are ones with long cooling and short heating seasons, but cool roofs can reduce energy costs in much of the country. Roofs with high thermal emittance — high ability to radiate heat — and high solar reflectance are said to be cooler in the sun. The same is true of low-emittance roofs with very high solar reflectance.

Incentives for cool roofs have appeared in some Sunbelt states. For example, CEC is currently offering rebates on cool roofing that generally run 15 cents per square foot. The rebates have been ongoing for two years and remain at least through 2003. The state is running out of money for the program, but regulatory action is expected to resolve the situation.

In Florida, FPL offers an incentive of 15 cents per square foot to commercial and residential customers for a good reflective roof with a long life that on average costs about $1 per square foot installed, FPL’s Muccio says. “We’re promoting cool roofs for any of our customers who are replacing part if not all of an existing roof.”

With FPL, any light-colored thermoplastic roof membrane or reflective roof coating is eligible for an incentive as long as the reflective measures are installed over the conditioned building space, meet the Energy Star standards and increase solar reflectance by a minimum of 73 percent.

FPL has a network of more than 1,000 certified installers eligible to do the roofing and other energy efficiency work under its Commercial/Industrial Building Envelope (CIBE) program. Incentives for customers come as part of CIBE “certificates,” which are given by the contractors to qualifying customers that are prescreened by the utility.

California Title 24
California’s stringent building code efficiency standards, Title 24, are currently being overhauled and upgraded. Cool roofing is cited in the standard in a small way, but under the current proposal it will become a much more important part of the code in 2005. Title 24 is mainly for new construction, although a reroofing section is planned.

Two key measures — solar reflectivity and thermal emittance — are included in the proposed Title 24 standards for nonresidential buildings. Now a compliance option, the cool-roof standards will become a prescriptive requirement for low-sloped roofs with a ratio of rise-to-run not exceeding 2:12. High-sloped and residential roofs would be exempt. Buildings covered by the new requirement are offices, retail stores, health care facilities, schools, universities and high-tech manufacturing facilities.

Title 24 specifies rules for certification and labeling of solar reflectance and thermal emittance roofing products, using third-party testing of these two measurements. That differs from Energy Star numbers, which are supplied by product manufacturers exclusively.

Energy Star
The Energy Star program provides information on roofing products. To be an Energy Star qualified product, the material needs to have an initial reflectivity of .65. The highest rated products are in the .85 range. Details are on the agency’s Web site, which includes 18 pages of products, including membranes and coatings that claim reflectivity measures ranging from a low of .70 to highs of .91 on a scale of 0 to 1.0; scientists say a score of 1.0 is impossible. More than 150 manufacturers are listed on the site.

Roof products that meet or exceed the .65 solar reflectance level, without compromising product quality and performance, qualify for the Energy Star label, according to officials at EPA. Through a voluntary agreement, manufacturers put the Energy Star label on packaging for qualifying roof products and use the label in promotions and advertising of the certified products.

Professionals recommend that facility managers check local utilities or other sources for third-party verifications of reflectivity claims.

National requirements under Energy Star aren’t as stringent as what is proposed in the upgraded California Title 24 requirements. For example, a low-slope cool roof can qualify under Energy Star with a reflectivity factor of .65, compared with .70 for California’s proposed new requirement. Steep-slope roofs can be as low as .25 for reflectance under Energy Star.

LEED Rating System
One other tool available to the building community is the Leadership in Energy and Environmental Design (LEED) rating system that has been developed by the decade-old U.S. Green Building Council (USGBC) in Washington, D.C. LEED has no specific criteria for cool roofs, but the use of them in connection with various urban heat island mitigation measures can help a building meet LEED criteria.

“We have one credit in particular within our sustainable sites category that specifically addresses landscaping and exterior design to reduce heat island and gives credit to projects that use light-colored, high-albedo materials,” says Emily Turk, USGBC’s chief architect. “It also gives credit to projects that use Energy Star high reflectance roofing or green-vegetation roofs.”

“The difference between a highly reflective roof and a more conventional, or ‘dark’ roof, can be something like a surface temperature difference of 50 or 60 degrees,” says PGE’s Turnbull. “Ambient temperature might be 110 degrees in the summer in the Central Valley of California. The temperature of a conventional roof might be 180 degrees, and a surface temperature of a cool roof with high reflectivity might be 120 degrees. When you think of the Delta-T, if you want to keep the inside space at 75 degrees, there is a tremendous difference between a surface that is 180 degrees and one that is 120 degrees.

“A cool roof is going to be a little bit warmer than the ambient temperature, but not much,” he says. “There is no doubt it saves energy, and we think there is some pretty good evidence that you get better life of the roof when you’re not dealing with the real extreme temperatures. All things being equal, cool roofs can extend the roof’s life.”

Please also see the March 2003 article by Richard Nemec titled "Push for Cool Roofs Runs from Rebates to Mandates"

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Monday, July 18, 2011

Your Estimate Can Cost You Credibility

Today's tip from the Work Smarter Not Harder team is about roofing estimates. When your estimate is presented as a perfectly round number (e.g., $58,000), it might look cleaner on a proposal and make things easier for the client, but most people will think it is highly unlikely that the estimate is that exact figure, and will assume you have rounded upwards and wonder by how much ($500, $1000, $5000?) as round numbers are always fake.

This may seem like a minor detail to you, and maybe it is, but it isn't to clients. And as you know, people will come up with hundreds of different reasons not to do business with you. It may even seem silly, but some roofing contractors will issue their very first invoice with invoice #436 (or something similar) to give the impression that they didn’t just start their businesses.

This likely won't change your success rate by an enormous amount, but if you are the only roofing contractor bidding a more precise figure on a job that could be a major factor in your winning it (you appear more honest and straight-forward with the client than your competitors). It's a little thing that can make a huge difference.

Please also see the post titled "Can Your Estimate Cost You Credibility?"
Tired of labor problems and low profit margins? Make more $$ spraying coatings with Conklin Roofing Systems!
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Friday, July 15, 2011

Metal Cool Roofing with Infrared-Reflective Paint Pigments

New infrared-reflective pigments are being incorporated into paints used on architectural metal roofing products to allow them to achieve higher reflectivity values, even in darker colors such as black and brown. This improved reflectivity (e.g., black changes from 0.07 with normal pigments to 0.32 with infrared-reflective pigments) can mean a much cooler surface temperature and thus greater energy savings for the building below, and allows facility executives to select a sustainable roof without having to sacrifice color choices and aesthetics.

To get the one point for Sustainable Sites Credit 7.2: Heat Island Effect, the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) green building rating system specifies Energy Star requirements, adding a 0.9 emissivity standard. For steep-sloped roofs, those with a rise-to-run ratio of 3:12 or greater, a 0.25 initial solar reflectance is required. In most cases, coated metal roofs can easily surpass the reflectivity requirement, and in some cases, they can achieve the 0.9 emissivity. But more often, they can only achieve an emissivity of 0.85, thereby eliminating them from achieving the LEED point.

For low-sloped roofs, those below 3:12, and flat roofs, the LEED reflectivity requirement is raised to 0.65, and the 0.9 emissivity standard is the same.

The Cool Metal Roofing Coalition, an organization comprised of metal industry trade associations, is providing written commentary and data to USGBC requesting consideration for a reduction of the emissivity standard to around 0.7. The Coalition contends that in addition to metal roofing’s energy efficiency when the reflective pigments are incorporated into a system’s design, metal’s long term ability to retain its reflective properties and a low life-cycle cost justify reducing the standard. The 0.9 standard “restricts a building owner’s ability to apply a suitable, long-term roof,” says Greg Crawford, executive director of the Coalition. The emissivity standard of 0.9 “is somewhat arbitrary,” says Andre Desjarlais, program manager for the Building Envelope research program at Oak Ridge National Laboratory, a supporting member of the Coalition. The 0.9 standard “is not defensible, but neither is eliminating emissivity altogether. We’re searching for middle ground.”

Please also see the March 2004 article by Greg Zimmerman titled "Do Cool Roofs Fit In Cool Climates?"

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Thursday, July 14, 2011

Reflective Coatings for Asphalt Roofs

If you spend more money and energy on cooling than on heating, you can cut this summer's air conditioning bills by investing in a reflective roof coating.

The main options for coating an asphalt roof are white polymers (like those from Conklin) and asphalt-like resins with reflective aluminum flakes. Both are reasonably priced, and offer short payback periods.

Why use a reflective roof coating?
Flat asphalt roofs reach up to 200 degrees Fahrenheit and absorb up to 70% of the solar heat blasting onto the building. By contrast, the best reflective roof coatings reflect up to 80% of solar heat, and can reduce surface temperatures on a roof by 80 degrees.

This can cut internal building temperatures by up to 10 degrees, increase the effectiveness of the insulation, and cut cooling energy costs by 25-70%. It also makes the building more comfortable in hallways or other areas that may not be air conditioned, and the roof will last longer without as much heat-related cracking and deterioration, saving money and materials in the long run.

White Reflective Roof Coatings
High-quality white polymeric coatings like those from Conklin are made with acrylics or similar materials mixed with an opaque, white and reflective pigment. They are probably the most effective reflective coating for the majority of asphalt roofs. There are also polymeric coatings that are tinted for aesthetic reasons, but they are less reflective and therefore won't save as much energy.

Tests at Oak Ridge National Laboratory and Lawrence Berkeley National Laboratory showed white elastomeric coatings offer about 60% solar reflectance, leaving the roof temperature 36 degrees higher than the ambient air temperature - a much smaller difference than that generated by a black asphalt roof. All polymeric coatings must be chosen and applied carefully, particularly on rough asphalt roofs.

Aluminum Reflective Roof Coatings
Metallic reflective coatings may be better for some rough asphalt roofs. They use asphalt-like resins and other materials mixed with aluminum flakes. The aluminum rises to the surface of the coating as it sets, creating a solid, reflective surface. Metallic coatings are rated at 55% reflectance, which is similar to the elastomeric coatings. But aluminum typically has higher average temperatures than elastomeric-coated roofs. The aluminum retains heat more than elastomeric coatings.

Calculate Your Savings
The federal government does not offer energy savings rebates for reflective roof coatings, but you can look for Energy Star-rated roof coatings, which guarantee a minimum level of reflectance.

Oak Ridge National Laboratory and Lawrence Berkeley National Laboratory also have a roof savings calculator. It uses weather data and your building information to estimate the cost of a new roofing system or coating, and the potential energy savings. The calculation tool is in the beta phase and is not fully automated. After you plug in data, the lab will email you results.

Again, buildings in hot climates and heavily use air conditioning will benefit in comfort and energy savings from a reflective roof coating like those from Conklin.

Please also see the May 2010 article by Steve Graham titled "Reflective Coatings for Asphalt Roofs"

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Wednesday, July 13, 2011

Different Substrates Require Different Roof Coatings

Once you determine a roof coating’s function, you must also consider the type of roof system being coated. Coatings suppliers and manufacturers like Conklin generally offer two types of coatings: all-purpose (suitable for a range of substrates) and application-specific (tailored to one type or a limited range of substrates).

It is important to know that different substrates require different roof coatings. For example, it is more difficult for coatings to adhere to hard, smooth, chemically-inert surfaces and easier on rough, irregular, chemically-active surfaces.

Coating adhesion to a substrate improves when the installer applies a primer or base coat. Manufacturers like Conklin recommend certain primers or base coats to match a specific top coat with a specific substrate. You should use only the base coat or primer specified by the coating manufacturer.

Primers and base coats for built-up roofs offer good examples. Manufacturers have designed products specifically to work on these surfaces - they work well on these often-hot surfaces by bonding to the asphalt and preventing it from bleeding into the white topcoat.

Enhancing a coated roof’s sustainability requires re-coating to extend service life. Most coatings are field-applied, and success depends on real-world conditions and the skill of the installer. To ensure proper curing, an experienced roofing contractor should pay careful attention to consistent application and changing weather conditions.

Please also see the March 2009 article by Reed Hitchcock titled "Different Substrates Require Different Roof Coatings"

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