Letters

Questioning the cool roofing movement

As roofing contractors, we can appreciate the fact that building owners and facility managers wish to lower energy costs by reflecting as much sunlight as possible from their buildings. However, "The cool roofing movement," January issue, page 16, smacks of "The Emperor's New Clothes." Should we throw logic and past experience out the window when considering roof systems?

Let's start with heat islands. It is merely logic that tells us where buildings, vehicles and people are abundant, temperatures will be greater than in rural wooded areas. Obvious, also, is the fact that concrete, asphalt pavement and building materials absorb sunlight and increase the temperature in urban settings. Other obvious factors that increase temperature in urban areas are the abundance of vehicles with engine operation temperatures of more than 200 F (93 C); hot emissions from vehicles; and heating, ventilating and air-conditioning exhaust from conditioned facilities. Because roof areas may provide about 10 percent of the surface area in an urban center, should we now target curtain walls of buildings for "cool" coatings? How about asphalt pavement?

I have found no empirical evidence that suggests changing the color of a roof system from gray to white will reduce the temperature of an urban heat island. There also is absolutely no evidence that reducing the heat island effect will increase a roof system's lifespan. In addition, the article's claim that "high reflectivity and emissivity of cool roofs can reduce the heat island phenomenon" is an unproven statement. These factors may provide benefits for a properly designed and installed roof system, but if the roof system is relatively small, on a high-rise building with dark exterior cladding/walls and surrounded by buildings with similar exteriors, the roof system will do little to reduce the heat island effect.

With more than 14 months of proven field performance of the Cool Roof Ratings Council's (CRRC's) product ratings, how can we not jump on the bandwagon? Because its "credible radiative-energy performance rating system for roof surfaces" doesn't have a damn thing to do with long-term waterproofing performance. It apparently only affects "the quality of the rating of products submitted by roofing manufacturers." And past experience shows us that many light-colored roof systems have weathered poorly over time. Remember unreinforced PVC? Severely surface-crazed CSPE? White EPDM? I don't ever remember seeing a built-up roof system with aluminum surfacing shatter though it may not have had the initial solar reflectance of PVC. Just because a product is light-colored doesn't mean it will provide long-term waterproofing capabilities.

With that said, light-colored roof systems are a good idea, but let's not knee-jerk our way onto the bandwagon yet. There is no better test for these "cool" products than time. I recommend caution because a CRRC-rated product is not a panacea. For those who jump on the bandwagon based solely on CRRC ratings, remember: We contractors will be glad to keep replacing roof systems every few years!

Scott Baxter
CRS Inc.
Monroe, N.C.

Following is CRRC's reply to the letter:

"We agree with Baxter that cool roof properties (solar reflectance and thermal emittance) should not be the sole basis for roof product selection. CRRC simply provides a rating system designed to provide accurate, credible information regarding these properties for those who wish to know.

"Regarding the matter of heat islands and cool roofing, we leave it to Professional Roofing readers to review the data and information provided on Berkeley, Calif.-based Lawrence Berkeley National Laboratory's (LBNL's) Web site, eetd.lbl.gov/heatisland, and draw their own conclusions. Regarding cool roofing and product life, we suggested 'cool' roofs last longer than 'noncool' roofs—a consensus view in the roofing industry. However, we attribute this effect to reduced thermal stress on roofing materials, not reduced heat island effects as Baxter appears to conclude.

"Cool roofing reduces air-conditioning loads in many common building types and many climates, thus producing a series of benefits; none depend on heat island arguments. A building owner wins on two counts: first, lower cooling loads reduce sizing requirements for air-conditioning systems, reducing equipment cost; second, reduced cooling loads reduce the energy bill to operate an air-conditioning system. Both effects obviously are building- and climate-related. The sizing benefits especially are important when a roof area is large compared with the occupied square footage (irrespective of climate, generally). Energy bill effects, on the other hand, especially are important in warmer climates. Although in cold climates energy bill effects may be neutralized by increasing heating load requirements, air-conditioning sizing benefits are not affected by winter weather. Overall stability on the electric power grid, which is sensitive to peak loads from air conditioning, likewise benefits from cool roofing. Because most parts of the United States are 'summer peaking' from an electric grid perspective, this benefit applies across the country.

"These benefits notwithstanding, Baxter surely is correct to note cool roofing properties are one of several important criteria for selecting a long-lasting, effective, energy-efficient roof system."

Following is Hashem Akbari's reply to the letter. Akbari is leader of LBNL's Heat Island Group.

"CRRC has brought to my attention Baxter's comments regarding cool roofs and summer urban heat islands. I would like to contribute the following points that would be valuable to readers:

1. LBNL's Heat Island Group has analyzed and characterized urban surfaces in four metropolitan areas (Sacramento, Calif.; Salt Lake City; Chicago; and Houston) using high-resolution orthophotographic data. Based on these studies, the fraction of roof areas averaged over the entire metropolitan areas was more than 20 percent. This fraction may be much higher in downtown areas. The fraction of paved surfaces (streets, parking areas, driveways, etc.) over the entire metropolitan areas typically is about 35 percent to 40 percent.
   
   
2. 'Hot' roofs and pavements contribute equally to summertime urban heat islands, and they should be considered in mitigating urban summertime heat islands. Although the fraction of roof area is smaller than paved surfaces for the same solar reflectance, roofs can get much hotter than pavements because storage capacities of pavements are far higher than roofs. The higher roof surface temperature contributes more to warming of cities.
   
   
3. Excluding the crowded high-rise downtown areas, the contribution of anthropogenic heat to summer heat islands is far smaller than hot surfaces. In a typical residential area, daily average anthropogenic heat is about 1 watt per square foot; the corresponding solar intensity is about 30 watts per square foot. An increase of 20 percent in solar reflectance of roofs decreases the absorbed solar energy by 6 watts per square foot and reduces the warming rate of the city by the same amount. The complete elimination of anthropogenic heat only contributes 1 watt per square foot to the cooling of a city.
   
   
4. Thermal fatigue (expansion and contraction) is one of the major causes of material failure of roofs and pavements. This has been studied extensively, and there is an abundance of data Professional Roofing readers can read.
   
   
5. There is sufficient empirical data showing the effects of dark surfaces on heat islands. Many books and articles have documented the effects of hot surfaces on urban heat islands.
   
   

"I encourage Professional Roofing readers to visit the Heat Island Group's Web site, eetd.lbl.gov/heatisland."

Readers disagree with Dick Baxter

This letter is in response to "Observations for 2004" by Dick Baxter, president of CRS Inc., Monroe, N.C., published in the January issue, page 25. Although Baxter makes some excellent commentary about Dens Deck, reverse auctions and wider single-ply sheets, I must take exception to some of his thoughts with regard to ENERGY STAR® and cool roofing. Baxter references the inherent need for watertightness and long-term performance. However, anyone seriously involved in this industry would define these as "must haves" whether a roof system has an ENERGY STAR rating or not.

There is an overwhelming and growing mountain of factual evidence that supports cool roofs and their abilities to reduce air-conditioning costs and prolong roof system life. This is true not only in warmer climates but also in northern latitudes. One only needs to look at the studies done by the Energy Coordinating Agency of Philadelphia; Rohm and Hass, Philadelphia; Lawrence Berkeley National Laboratories (LBNL), Berkeley, Calif.; NASA Urban Climatology and Air Quality studies; and Cool Communities, Rome, Ga., to see the weakness of Baxter's argument.

As for sun load being less in northern climates, all energy calculators already factor this important parameter into the mathematical model. The programs require input for specific geographic locations with heating and cooling degree days. The fact that the sun is at a lower angle in the winter and the days are shorter already is factored into the data input.

I agree with Baxter that a white roof or any roof should be designed and built to provide drainage and eliminate ponds. This is sound roof system design and installation practices and has significantly more to do with roof service life than color.

Yes, roofs may become dirty during their service lives. This means the energy savings realized from a white membrane will be less than original if it's not cleaned during its life. However, a rule of thumb that often is used by the design community and energy professionals is to expect about 80 percent of the initial values for reflectivity as a long-term coefficient. This has been developed experimentally by LBNL. I agree with Baxter that cleaning may not become a revenue stream for the typical roofing contractor.

Thanks to Professional Roofing for continuing to offer Baxter this annual courtesy. He's absolutely correct that the roofing business is dynamic, and there always will be new and controversial topics for him to write about. I'm grateful for the opportunity to comment on them in this forum.

William A. Kirn, RRC
National Coatings Corp.
Camarillo, Calif.

Following is Baxter's reply to the letter:

"I would certainly hope anyone 'seriously involved in this industry' would define watertightness and long-term performance as 'must haves' whether a roof system has an ENERGY STAR rating or not. The energy load calculations may factor sun load into the 'energy' equation in northern climates, but energy values are not the only consideration in evaluating the effects of 'cool' roofs on overall roof system performance in areas of heavy snow loads.

"Pardon me if I appear skeptical about cool roof claims; I have yet to be convinced that the claims are not exaggerated and that most owners are willing to preserve the reflectivity of cool roof membranes with regular cleaning. I see a lot of roofs that can't possibly provide 80 percent of the initial reflectivity values because of accumulations of dirt, fungus, etc., which leads me to believe the 'rule of thumb' may be slightly on the optimistic side.

"Thanks for your comments, and I promise to try to keep abreast of realistic evaluations of roof system reflectivity."

I am writing to express my concern about "Observations for 2004" by Dick Baxter and the obvious lack of peer review by Professional Roofing magazine. Usually, I consider Professional Roofing to be, well ... "professional." In this case, the magazine failed to meet that level of care.

The article contains a number of blatantly obvious errors and presents information that is so lacking in complete coverage to be considered suspect. For example:

• Under the subhead "ENERGY STAR," Baxter's statement that the "Oak Ridge National Laboratory (ORNL), after spending a few million tax dollars on an 'Energy Chamber' that rarely has been used ... " is not correct for two reasons. First, there is no such thing as an energy chamber. Second, if Baxter had done his homework, he would have found that ORNL's activities are reviewed by the U.S. Department of Energy (DOE) and the information is available.
  
  
• With respect to the discussion concerning Chicago, Baxter fails to mention the other aspects the city council considered as part of adopting the Chicago Energy Conservation Code-Urban Heat Islands/Roof Reflectance provisions, such as reducing the amount of peak energy demand during summer months and increasing air quality.
  
  
• The article also suggests DOE has control over the U.S. Environmental Protection Agency (EPA). Baxter writes, "From the desperation of [ORNL] to survive, the ENERGY STAR concept of reflective roof system came to be ... ." In my discussions with DOE and EPA staff, no such hierarchical relationship exists.
  
  
• The article indicates an increase in cost because of " ... the inevitable costs of maintaining reflectivity of the roof surface. That will mean regular cleaning ... Can the costs of maintaining reflectivity be offset by energy savings?" Let's not forget the obvious drawbacks about not regularly maintaining any roof—something about which even NRCA has been proactive.

In conclusion, the article is less than the quality of work I usually expect Professional Roofing magazine to produce.

Jonathan Humble, AIA
West Hartford, Conn.

Following is Baxter's reply to the letter:

"As is clearly stated in Professional Roofing, the views expressed are mine alone, and I should be personally chastised—not NRCA or Professional Roofing.

"I appreciate your comments, but until someone is willing to expound on the 'costs' of promoting this concept and what kind of 'payback' an owner can expect in various geographic areas, the hype is incomplete. Cleaning roof surfaces is not viewed as typical maintenance by the average consumer and most likely will occur only on high-profile facilities."

This letter is written in rebuttal to "Observations for 2004." Specifically, I would like to discuss the article's claims about ENERGY STAR® and references to Oak Ridge National Laboratory (ORNL), Oak Ridge, Tenn.

Describing the origin of ENERGY STAR, Dick Baxter states, "Oak Ridge National Laboratory ... finally sold a concept to justify its existence to the U.S. Department of Energy (DOE) ... ." This assertion not only is offensive, it is wrong. The issue of cool roofs started with the U.S. Environmental Protection Agency's (EPA's) Urban Heat Island Initiative with Lawrence Berkeley National Laboratory (LBNL), Berkeley, Calif., and not the "desperate" DOE or ORNL. These factual deficiencies are all the more glaring in light of the article "The cool roofing movement" that appears a few pages before Baxter's article.

Furthermore, his assertion that ORNL has spent "a few million tax dollars on an 'Energy Chamber' that rarely has been used and [has failed] to convince the world that saturated insulation in existing roof systems could be dried using unorthodox roofing methods" implies a familiarity with our program that doesn't exist. Baxter has not been in contact with us nor has he visited our facilities in at least 15 years, yet he portrays himself as knowledgeable about our activities. Before expounding on his perception of deficiencies in the building envelope research program at ORNL, Baxter could have taken the time to visit our Web site and learn more about our work.

For example, one element of research under way at ORNL is the development of an experimental procedure that accelerates the change in solar reflectance as a function of time. Baxter should welcome this work, which actually may produce data to support his personal biases.

Baxter refers to "imaginary calculations and general hype" and states, "White/reflective roof systems make much less sense in northern climatic areas, but that fact doesn't fit with the DOE existence justification program." One of the research projects supported by DOE at ORNL and described on our Web site is the development of reasonable estimates of the energy benefits of cool roofing. In fact, this research was described in "Cool low-slope research," July 2001 issue, page 24. The article describes in some detail the DOE Cool Roof Calculator, which ORNL validated against field studies performed with the Roof Coatings Manufacturers Association and SPRI.

Baxter also could have reviewed Proceedings of the 12th International Roofing and Waterproofing Conference where he would have found that this tool actually yields results that agree with some of his ramblings. Yes, the energy savings benefits decrease as the cooling load is reduced. Yes, roofs "age" and lose some of their solar reflectance. I would suggest it is not DOE that ignores facts that disagree with their preconceptions but Baxter.

Baxter asserts that ORNL must sell "a concept to justify its existence to DOE." In fact, DOE requires us to hold program planning sessions with industries to determine the greatest needs in building sectors. DOE also has ORNL undergo regular peer reviews for the technical content of its work with the objective of determining whether work should continue or be redirected elsewhere.

At ORNL, we still are required to have our documents reviewed by knowledgeable technical experts before we publish our articles. Baxter should have made a reasonable effort to find out the whole story before making his broad derogatory statements. I invite Baxter to visit ORNL and see the breadth of research conducted by the Building Envelope Group. The list is much longer than he suggests.

André O. Desjarlais
ORNL
Oak Ridge, Tenn.

Following is Baxter's response to the letter:

"Although I always appreciate being factually corrected, I remain unconvinced about the benefits being touted. Some more objectivity is in order.

"My last visit to ORNL left so many questions unanswered that I've never attempted to return. The major information missing from all the 'calculations' is economic 'payback' to owners who buy into this concept. Good roof system performance depends on many more factors than reflectivity. In the past, I've publicly chastised the U.S. government's position on energy conservation, personally believing that much more could be done to encourage energy-efficient roof systems. The present track doesn't seem to provide any more direction than past efforts."

In support of Bush's plan

Thanks for the informative article about Bush's proposed alien work program plan ("A subject for debate," February issue, page 5). The quote from Dean Murphy of The New York Times just shows the ignorance of most Americans, especially East Coast residents, concerning what "illegal immigrants" do for our economy and country.

In the Southwest, they fill critical high-skill trade jobs, not just menial jobs referred to by Murphy. They are paid the same wage as any other similarly qualified worker and pay billions of dollars into the income, Social Security and Medicare tax systems for which they get nothing in return.

I believe Bush's ideas are great and certainly no different than "outsourcing" that is praised in most industrial situations. The only difference is these illegal immigrants are helping solve the underfunded Social Security and Medicare systems for Americans who have not paid in enough to offset their legal benefits. What a great deal for America!

Registering illegal aliens will help eliminate the situations where employers pay cash and don't pay the required taxes. The only difference I would favor from Bush's plan is to only give them their portion (not employers' portions) of Social Security benefits unless they become citizens, in which case they would get their full benefits.

David May
D.R. Kidd Co. Inc.
Round Rock, Texas

A request for quality roof systems

Thank you for a good article addressing design mistakes often made in the roofing profession ("Top 10 design mistakes," March issue, page 46). I understand most NRCA members probably are larger contractors interested in the issues that affect them relating to larger projects. It appears roofing has become a numbers game in which the "cheapest" roof system installed by the "lowest" bidder seems to prevail. Coming from a midsized company that has been in my family for three generations, I find this numbers game and resulting bid market have cheapened roofing and encouraged lower standards in our industry. This probably also is true in many other trades serving the construction industry, but I take offense when my roofing company is forced to defend itself and justify the higher cost of performing quality work.

In our company, we have learned during the course of many years that "negotiated" work is the only way we still can install quality roof systems and stay profitable. This works fine with our long-time repeat customers. It's the "new" roofing consumers who do not understand that a cheap price along with a 20-year warranty often results in a severe reality check when the roof system and contractor do not live up to expectations. Often, I am called in by a building owner who is having problems and doesn't want to ever see the original contractor again. I have to tell him it's more cost-effective to replace his roof now than to attempt repairs on a roof that is not that old.

Why do so many roofing consumers have to learn a hard, expensive lesson when it comes to such an important part of their buildings? What can our industry do to raise the standards of contractors along with the quality of the systems we sell? How can we educate designers so they know what systems work best, are the most durable and last the longest?

No roof system is any better than the contractor who installs it, but there are many roof systems—steep- and low-slope—that are time-proven. There has to be a better compromise. Consumers are not getting all the facts and options. Many designers can draw nice pictures, but few know good roof system design and fewer know good flashing details. Manufacturers often sell a high-end system and lesser cost system but offer the same number of years of warranty coverage for both and sell them as "equals."

With the ever-rising cost of materials and labor, why doesn't our industry heed the call and produce and install a better product? As an NRCA member, I would like to see my association make a better effort at defining quality as it relates to contractors, roof systems and roof system design. It's a waste of time, money, materials and the reputation of our industry to fail to improve our product.

James Pickard
Pickard Roofing Co. Inc.
Durham, N.C.

Following is Professional Roofing's response to the letter:

"Thank you for your comments. NRCA has recognized the need for quality roof system installation and materials. In fact, NRCA announced in 2003 its Performance Criteria for Constructed Roof Systems (PCCRS). Preliminary information about PCCRS can be found in 'New council, new standards,' July issue, page 15; however, much work has been accomplished since then.

"For more information about PCCRS, contact Mark Graham, NRCA's associate executive director of technical services, at (800) 323-9545, Ext. 7555, or e-mail mgraham@nrca.net."