By Drew Ballensky
According to a 2005 Roofing Industry Alliance for Progress survey of building owners, the three most important considerations for selecting a new roof are, in order of priority: 1) installed cost, 2) the quality of installation, and 3) life-cycle costs (LCCs). Of those three, the only surprise is the high ranking of LCCs, which is a relatively new concept. One reason for the emergence of LCC roofing analysis is the growing sustainable building movement, which endorses energy-efficient and long-lasting roofs. Both of these characteristics can contribute to lower roofing life-cycle costs.
Unlike installation costs, which have the precision and immediacy of a payable invoice, LCC estimates include future considerations like longevity, maintenance and repair, and potential savings from energy efficiency. LCC estimates are inherently less precise, but they are a useful guide to value over time.
This is especially true with cool roofing, where energy savings can make a big difference in the 20-year cost of a roof. In 2004, a hypothetical, 20-year LCC comparison was prepared with the help of independent Midwest roofing contractors. The objective was to compare the LCC of an established cool-roofing system (a white PVC single-ply system) with traditional black EPDM and asphalt built-up (BUR) systems for a fully warranted, 50,000-square-foot re-roof in the Midwest. To determine energy savings, the EPA Energy Star® cool roof comparison calculator was used (http://roofcalc.cadmusdev.com).
Although far from perfect, this hypothetical life-cycle cost comparison clearly demonstrates the impact that energy efficiency can have over time. The total installed costs - the cost of the roof product, installation, tear-off, and disposal - are similar: $142,500 for the traditional black systems and $133,000 for the white PVC cool roof.
Estimated maintenance and repair could vary considerably depending on the type of roof, but these costs are relatively low compared with other variables. Both BUR and EPDM roofs typically have regular repair schedules to maintain watertight integrity; PVC systems are hot-air welded, so repairs are needed only for accidental damage.
The biggest difference is clearly in energy savings, where the cool-roofing system saves the building owner an estimated $4,200 a year. This may be a conservative estimate considering the continuing upward spiral of energy prices.
Dramatic differences between installed costs and estimated life-cycle costs are the main reason building owners are increasingly asking for a good LCC analysis before making a final decision.
Drew Ballensky is general manager at Saginaw, MI-based Duro-Last Roofing Inc.’s Sigourney, IA, plant (www.duro-last.com) and spokesman for the Duro-Last Cool Zone® roofing system.