Why Settle for a 17-Year Roof System?
Posted: April 16, 2021 | Project Management
It has been 18 years since Ducker Worldwide released its findings from a well-known study that stated the average life expectancy of a low-slope commercial roof is only 17 years. It should have been a wake-up call to building owners and design professionals to demand more from their roofing systems. But that still holds true today, despite all the construction and design community’s chatter about sustainability.
Durability is one of the hallmarks of sustainability. Yet, given today’s demands for short-term profitability, it is understandable that building owners feel more pressure to achieve lower initial costs than to reduce life-cycle costs. With 75% of the commercial building market demanding improved energy efficiency and more sustainable buildings, it is time the correlation between durability and sustainability be acknowledged. No one should settle for a 17-year commercial roof — especially not schools, hospitals, government facilities, and many industrial operations where the typical service life of their buildings is more than 50 years.
Roofing is a demanding profession requiring skilled labor, and even highly trained and experienced roofers cannot be expected to perform each job 100% perfectly every time. Is a 95% success rate good enough? On a typical 50,000-square-foot roof, there could be over one mile of single-ply seams that must be expertly welded to achieve watertightprotection. At a 95% success rate, this would result in nearly 400 linear feet of potential seam problems. Alternatively, a multi-ply roof system provides inherent redundancy which is less dependent on the installer, and will increase system resilience while reducing the potential for leaks. So why not design and construct a system that is engineered with redundancy and multi-ply protection?
It’s been said that roof slope is the wisest investment a commercial building owner can make when seeking a longterm watertight solution. But “meeting code” is not always enough to ensure sufficient drainage. Experienced roofing professionals have learned that the “ideal” slope is whatever it takes to get the water off a particular roof.
Rooftop equipment, undersized drain sumps, incorrect or poorly installed crickets between drains, clamping rings, and countless other factors can impede the flow of water. Often drains are installed at column lines and, with a little bit of deck deflection, water gets near the drain. For optimal roof performance, close to the drain does not count — water must be funneled down the drain and not allowed to pond on the roof.
Mind the Details
Roof design details must be project-specific, not generically pulled from a “standard” list off the internet. As stated in The Manual of Low-Slope Roof Systems, “Generally recognized as the major source of roof leaks, flashing demands as much of the designer’s attention as the basic roof components.” It is the responsibility of the roof designer and roofing material manufacturer to create the proper flashing design that will be covered by the manufacturer’s long-term warranty. Leaving it up to the contractor to figure out the tough details on the job often leads to leaks and premature roof failure.
Roof Edge Design and Construction
Strong perimeter edge details will increase the integrity of the roof system, extending the service life of your roof. A study of 145 Factory Mutual Global insurance losses involving commercial roof systems showed 85 losses (59%) occurred because the roof perimeter failed. Therefore, premium metal edge systems meeting ANSI/SPRI ES-1 requirements should be specified. Pre-manufactured edge metal systems — combined with proper engineering, design, and installation — will ensure the building owner of long-term performance at the perimeter.
Periodic Inspections During Roof Construction
If your roof is inspected only after the installation has been completed, how can you be certain the many details of construction have been properly installed? Periodic inspections during installation of the new roof system is the best protection against installer error or simple carelessness. The National Roofing Contractor Association (NRCA) states the most effective means to evaluate the quality of the roof installation is by thorough visual examination at the time of application by a trained professional who understands the roof system and good workmanship practices. Owners who desire long-term solutions should insist on periodic inspections during roof construction.
Neglected Maintenance Shortens Roof Life
The topic of roof system longevity would not be complete without a strong acknowledgment that no roof, no matter how durable the material or expert the installation, will realize its potential life span without regular preventive maintenance. Just as with your car, HVAC, and every other complex system you own, the modest dollars spent on routine maintenance are essential to long-term performance. If your roofing “expert” tells you differently, you may want to find another roofing professional to trust.
A 50-year roof is not a pipe dream. As stated in The Manual of Low-Slope Roof Systems, there are roofing materials and systems “with long records of proven performance and thousands of roofs still performing satisfactorily, some after service lives of 30 to 50 years.” This is achievable today, with the materials presently on hand, for building owners and architects partnering with manufacturers, design professionals, and contractors committed to the craft and art of proper roof design, construction, and installation. Industry veterans remember when this was common in our industry. Building owners that focus on longevity should insist on superior, durable roofing solutions.
Brian Lambert is a 28-year veteran of the commercial roofing industry. He has extensive experience in all types of low-slope commercial roofing systems, and has personally inspected thousands of buildings across North America. He led the product and technical teams at The Garland Company, Inc., www.garlandco.com, in Cleveland, Ohio, for many years, and currently is the General Manager of Design-Build Solutions, Inc., a Garland Industries subsidiary that manages hundreds of commercial roofing projects across the United States each year.