Something Old, Something New

Installing solar power on existing buildings can be a daunting challenge. Experts point to several key factors to evaluate when making the decision to add photovoltaic panels to a roof system, including a structural analysis to determine if the building has the ability to withstand the added loads and a thorough review of the roof system. Key considerations include the age of the existing roof and whether it will perform for the expected life span of the solar panels.

Brian Neely, AIA, CDT, BECxP and Jeffrey Ziske, P.E., CDT, both with building enclosure consultants Gale Associates Inc., do a great job of detailing these key variables in the article in this issue titled “PVs and Their Impact on Roofing Assemblies.” They recommend doing a cost-benefit analysis to determine whether the roof should be repaired or replaced prior to installing solar, noting, “Needing roof repairs/replacement halfway through a PV system lifespan can be problematic and potentially costly in both construction costs and lost PV energy revenue.”

When you add in warranty considerations, code requirements, and ongoing maintenance, it’s enough to make your head spin. This article was top of mind for me as I interviewed contractors for this issue who put these theories into practice. The projects profiled in this issue show contractors going different routes to achieve the same goals — installing the right systems for the building in the most cost-effective method.

For the Stirling Road Branch Library in Hollywood, Florida, a new roof was the answer. When the team from Advanced Roofing Inc., was called in to evaluate the library’s aging modified bitumen roof, they realized that it was the ideal time to add solar to the building. Advanced Roofing and its sister company, solar energy contractor Advanced Green Technologies, have been collaborating with Broward County to help it meet lofty targets for implementing renewable energy. The companies installed an energy-efficient PVC roof system and photovoltaic panels, which synchronized the expected lifetimes of both the roof system and the solar array.

When New Columbia Solar was designing a solar system for the historic building that now houses the Kimpton Hotel Monaco In Washington, D.C., they partnered with Fortis to evaluate the roof system. The team from Fortis determined that with some reconditioning and preventative maintenance, the existing metal and modified roof systems were excellent candidates to perform for the life of the solar array. Avoiding a reroof saved the hotel both time and money, and Fortis is providing a roof performance program and a robust warranty.

Doing the right thing for the building, the client and environment — one building at a time.

— Chris King