The Economics of High-Performance Roofing

Life-cycle costs are the third most important consideration – after installed cost and the quality of installation – according to the 2005 Roofing Industry Alliance for Progress survey of building owners. Clearly, economics is a very important criterion for building owners, and High-Performance Roofing systems must be economical if they are to become viable, real-world options.

One reason we hear more and more about the life-cycle costs of building materials and systems is the green building movement. Unlike immediate installation costs, however, life-cycle costing must estimate future considerations, such as longevity, maintenance and repair, and the long-term impact on overall facility operations. Life-cycle cost estimates are not as precise as installation cost estimates because variables can change, but life-cycle cost estimates can serve as a useful guide to the value of building system choices over time.

This is especially true with cool and solar-integrated roofing, where energy savings alone can make a big difference in the 20-year cost of a roof. In 2004 – before the most recent energy price increases – a hypothetical, 20-year LCC comparison was prepared with the help of independent Midwest roofing contractors. The contractors did all the estimating based on their years of experience installing and estimating many types of roofing systems. The objective was to compare the life-cycle costs of a High-Performance Roofing system – in this case, a white PVC single-ply – with popular black EPDM and BUR systems for a fully-warranted, 50,000 square-foot re-roof in the Midwest.

The PVC single-ply system was chosen because it is an ENERGY STAR-labeled cool roof system with the longest track record, dating back to the early 1960s. The black EPDM and BUR roofs were selected because they currently rank number one and two, respectively, in terms of market share for commercial roofing systems in the United States. Contractor estimates for the built-up asphalt roofs and EPDM single-plies were averaged. For energy savings, the EPA ENERGY STAR Roof Products Program cool roof energy savings calculator (available online at roofcalc.cadmusdev.com) was used, projected out 20 years.

This hypothetical life-cycle cost comparison clearly demonstrates the impact that an energy-efficient, High-Performance Roof can have over time. The total installed costs – the cost of the roof product, installation, tear-off and disposal – are pretty close: $142,500 for the traditional black system; $133,000 for the white PVC cool roof. The main difference here is the cost of tear-off and disposal for EPDM and BUR, which normally require a complete tear-off of the old roof before re-roofing. PVC single-ply systems are often installed directly over the existing roof, and require a tear-off only if the local code requires it, or if there is serious damage to the existing substrate.

Estimated maintenance and repair could vary considerably, but these costs are relatively low compared with other variables. Many roofing systems, including EPDM and BUR, require regular repair schedules to maintain performance. Thermoplastic single-plies are hot-air welded, so repairs are needed only when accidental damage occurs.

Energy savings are clearly the biggest difference, where the reflective PVC roofing system saves the building owner an estimated $4,200 a year. This is actually a conservative estimate considering the continuing upward spiral of energy prices. Not included in the LCC are the less tangible environmental benefits of the High-Performance PVC system – recyclability, reduced landfill waste, less air pollution and mitigation of the UHI effect.

The Custom Pre-Fabrication Advantage

Another means of achieving better economics is the use of custom pre-fabricated single-ply roofing systems. Precise measurements of each roofing job are sent to the factory in advance. The manufacturer then factory-seams large, custom-fit roof sections of up to 2,500 square feet under controlled conditions, as well as precisely cut flashings, edging and venting membrane pieces. Designed to fit every roofing job exactly, custom pre-fabricated single-ply roofing systems provide a number immediate and long-term cost and performance benefits, including:

• Less waste. Cut precisely to fit each building, the use of custom pre-fabricated roofing systems virtually eliminates installation scrap, reducing the number of landfill runs to just one.
• Less labor. Pre-fabricated into much larger sheets than typical single-ply rolls, these systems are installed with up to 50 percent smaller roofing crews.
• Less time: Even with smaller roofing crews, the custom-fit of a pre-fabricated system reduces the installation time, and building/facility disruption, by 50 percent or more.
• Less human error: Large, custom-fit single-ply rolls that are factory seamed reduce the amount of on-site seaming – one of the primary causes of roofing failures – by up to 85 percent.

For more information on High-Performance Roofing, visit www.duro-last.com