The integrity of any roofing structure is key to protecting employee comfort and safety, equipment and inventory investments, and the continuity of operations while containing energy costs. New techniques are being developed to minimize the onus of repairs and frequency of replacement, and to convert roofing liabilities into energy-producing assets.
Aerial inspections: Regular roof inspections and maintenance can add years to the structure’s life. However, conventional rooftop inspections are a time-consuming and risky endeavor, often with less-than-precise results.
Thermographic cameras detect the energy radiating from latent moisture in the roof. Moisture is indicative of leaks that might not otherwise be visible, and highly saturated areas could pose a structural risk. The energy loss also has significant economic consequences.
Infrared images are best captured after sunset, when a temperature differential is most evident. Aside from the obvious safety issues, walking a large industrial roof at night while peering through a thermographic camera could take days to complete. Furthermore, a large, wet area at sundown can look quite small by midnight, because only the most saturated areas will still show a temperature differential. The result is a compilation of findings with inexact measurements.
In contrast, aerial service companies capture the thermographic image of an entire roof in a single survey. By day, Predictive Service flies a plane over your facility and takes a standard photograph of the rooftop. During a second flyover shortly after sunset, a very high-resolution thermographic camera generates an infrared image. The two images are digitized and overlaid into a single, graphical representation that is colorized to indicate the specific location and degree of moisture damage.
The image is made available through the company’s Web-based ViewPoint software, which provides damage calculations, criticality, repair estimates and recommended corrective actions. It also tracks data about roof repairs and additions, such as the type, date, cost, roofer, warranty information and problems solved.
The aerial inspection provides precise measurements of current problem areas and emerging issues. The greatest benefit is in finding problems while they’re still minor and relatively inexpensive to repair. Unit costs for roof reconditioning can be expected to run less than half that of a new roof, saving some companies hundreds of thousands of dollars, according to the U.S. DOE.
Solar savings: If energy costs also are a concern, consider installing a photovoltaic roofing system on your existing roof deck. Photovoltaic systems convert sunlight to energy. The clean renewable energy source decreases peak electricity expenditures.
Solar Integrated’s Building Integrated Photovoltaic (BIPV) roofing system is lighter weight and more efficient than traditional crystalline-based solar panels. The system integrates a durable, single-ply roofing membrane that is both low-maintenance and waterproof, with lightweight, thin-film amorphous-silicon photovoltaic cells.
The integrated technology yields a weather-tight blanket of flexible solar panels that can be rolled onto existing flat or low-slope surfaces. Weighing just 12 oz. per sq. ft., it allows installation on most facilities without exceeding roof loading limits. Its rigid foam insulation and gypsum board fire barrier resist punctures and provide a Class A fire rating.
The BIPV system is capable of producing roughly 450 kilowatt-hours of solar power per day for every 28,000 sq. ft. of roofing material installed, and it produces electricity even when it’s cloudy. Also, it reduces rooftop temperatures by reflecting, rather than absorbing, insolation.
Along with reducing maintenance, the technology helps to offset the cost of public utility-supplied power and to stabilize utility bills. Some jurisdictions provide credit for feeding excess solar power into the local electrical grid. LEED-certified green buildings also have opportunities for national, regional and local utility rebates, tax credits and subsidies.
Ongoing research: Most roofing systems fail from leaks, and the average roof needs to be replaced four times, according to Oak Ridge National Laboratory (ORNL). In addition to replacement cost savings and construction waste reduction, ORNL estimates that if low-slope roofing systems could be kept dry, more than three-fourths of a quadrillion BTUs of energy could be saved each year in the United States.
With this in mind, ORNL’s Building Envelopes Program is researching new techniques to enhance roof drying potential; the effectiveness of re-covering as a re-roofing strategy, and the use of photovoltaic cells, highly efficient skylights and green roofs to enhance thermal performance.
E-mail Contributing Editor Sheila Kennedy, managing director of Additive Communications, at [email protected].
Reference Web sites:
www.ornl.gov/sci/roofs+walls
www.pscorp.com
www.solarintegrated.com
www1.eere.energy.gov
www.usgbc.org
www.rci-online.org
E-mail Contributing Editor Sheila Kennedy, managing director of Additive Communications, at [email protected].