The long-term performance of a roofing system can, in many cases, be predicted by the decisions made during the design phase of a school project. All too often, compromises or oversights at this juncture can lead to long-term headaches. More than ever, the specifier must be attuned to the finer points of roofing systems to ensure that the highest performance system is selected while still meeting the budget expectations.
Currently, a higher degree of focus is being placed on a roof's effects on the energy consumption within an educational facility. A number of manufacturers have introduced products to meet the demand for lighter-colored roofing membranes.
A study by Ducker Research Company examined perceptions of roofing materials, as well as what affected their selection. The respondents were involved in the selection of roofing materials for educational buildings, had completed an educational roofing project in the past 12 months and derived 25 percent of billings from educational (K-12) projects. The participants were: 71 percent specifiers, 17 percent school officials/facilities managers and 12 percent roofing consultants.
Respondents were asked to identify which roofing materials are best suited for education applications.
EPDM products were mentioned most often as the best fit for roofs on education facilities. The EPDM roofing products cited are single-ply synthetic rubber membranes. EPDM was preferred as a cost-effective means to obtain a roof with the necessary longevity to perform in a school environment.
The survey also sought to identify those areas that are most critical to evaluate when selecting roofing materials for education facilities. Open-ended responses were solicited to identify factors that most often are considered during the evaluation process.
The results (by percentage of respondents):
Product performs to specifications, and durability and quality: 65 percent.
Strong warranty: 46 percent.
Initial and total costs for materials/system: 37 percent.
Track record of company and products: 32 percent.
Service and support: 25 percent.
Availability of experienced contractors: 24 percent.
Clearly, decisionmakers responsible for selecting roofing systems are influenced more by a product's ability to perform in the long term. School decisionmakers preferred roofs that provided the required performance at an installed cost that remained competitive on bid day.
After a roof is installed, facility managers prefer roofs that will perform without problems for the period of the warranty. Across the board, longer-term warranties of 15 to 20 years are preferred. Funding requirements for public sector construction work may be a deciding factor in this area because premium systems are preferred in lieu of future maintenance spending, which comes out of operating budgets.
Recently, there has been a proliferation of enhanced EPDM products designed to perform in more rigorous environments. New variants of EPDM with improved puncture- and tear-resistance have been added. The new membranes incorporate enhanced reinforcement or fleece backings designed to resist damage to the roof system.
Money invested in a thicker or reinforced membrane is money well-spent because the additional amount spent stays on the roof and installation costs are virtually unaffected. Reinforced membranes as thick as 75-mils are providing the levels of puncture-resistance previously seen only with the multilayer asphaltic systems.
Within the Ducker survey, energy conservation was not identified as a primary factor in roof selection. Still, specifiers increasingly are trying to minimize energy consumption. The low usage of lighter-colored roofing systems indicates a preference for dark-colored roofs. There may be a lack of awareness of these newer systems. Alternatively, the lack of emphasis on this issue may indicate that other solutions may provide equivalent benefits.
Insulation levels used on school projects frequently negate the benefits provided by lighter-colored membranes. A study titled “The Impact of Reflectivity and Emissivity of Roofs on Building Cooling and Energy” by Lawrence Berkeley National Laboratory analyzed the impact of roof color on energy usage. The results indicated that at a minimum insulating value of R-11, the combined heating and cooling energy cost for the Chicago market was reduced by 23 cents per square meter by going from a black to a white roof. For Washington, DC. the savings projected was similar at 31 cents for the same minimal R-value.
Increasing the R-value from R-11 to a more typical R-19 provided a more substantial savings in the Chicago market. The energy consumed on a per-square-meter basis drops from $4.62 to $3.38 for a black roof. For the Washington D.C. market, savings followed the same pattern. Energy costs dropped from $4.12 to $2.90.
The conclusion is that improving insulation R-value can have a more significant impact than changing the color of the roofing system. This is especially true in northern climates where cooling days are fewer than heating days. Schools also merit unique consideration because of the low usage rate in the summer months. In such instances, the emphasis should be on achieving a cost-effective means to save energy in winter months. Given the school segment's primary concern of product performance, this means the use of increased levels of insulation.
In southern climates, where cooling days outnumber the heating days, a lighter-colored membrane may be the more energy-efficient. EPDM manufacturers have developed white versions of their product for such applications. Additionally, the new TPO thermoplastic systems provide highly reflective options that may in time prove to be equivalent to EPDM systems.
Top factors most considered during the roofing evaluation process (by percentage of respondents):
Product performs to specifications, durability and quality.
Initial and total costs for materials/system.
Track record of company and products.
Service and support.
Source: Survey by Ducker Research Company.
DuCharme is a marketing manager for Carlisle SynTec Incorporated, Carlisle, Pa.