Facilities (Campus Spaces)
Out of Sight...
Your roofs are one of your biggest assets. Proper selection and maintenance could stretch the life of these often overlooked building components to 20 years or beyond.
- By Amy Milshtein
- March 1st, 2014
PHOTO COURTESY OF PETERSEN ALUMINUM
John F. Kennedy famously said, “The time to repair the roof is when the sun is shining.” While he was speaking metaphorically, when it comes to actual roofs the statesman got it wrong. The time to repair a roof is before you even install it. Facility managers, builders and architects must consider many variables of these complicated systems before deciding on an appropriate cover to their building. After it’s installed, the real job begins as diligent maintenance means getting the most out of your roofs.
The One to Roof Them All?
“If there was one best roof, everyone would have it,” says Joan Crow, director of technical services, National Roofing Contractors Association, when asked about the different kinds of coverings available. What’s “best” depends on the style and use of the building, local climate, budget and desired life expectancy. The building’s design should direct your first choice, sloped or flat.
Sloped roofs work best for buildings that need to fit into the campus’s architectural vocabulary. “Student housing often features sloped roofs,” says Rory Green, quality director, McCarthy Building Companies, Inc.’s Northern Pacific Division. They can be made of different materials like wood composition, asphalt composition, standing seam metal or clay, cement or metal tile manufactured to look like wood. “Some Ivy League schools use slate on their roofs, but you have to insist on good workmanship,” continues Green. “Slate lasts a long time, but if it breaks free and falls it could cause injury.”
Most commercial buildings are topped with a flat roof… hopefully, one that is not too flat.
“It’s important that even a flat roof has some slope to drain standing water,” says Brian Lambert, director of products and systems, The Garland Roofing Company, Inc. “Too often we see shallowsloped roofs that are basically dead flat. That encourages standing water, which causes problems down the road.”
Flat roofs have many advantages. They are less expensive than sloped options, and their flat surface allows space for air-handling equipment. Keep in mind, however, that the dead weight of an HVAC system needs to be managed or your roof will develop leaks well before its time. “People often don’t take that into consideration,” says Lynn Valentz, vice president, PHP Systems/Design. “Managing dead weight takes engineering and thought.”
Valentz also cautions owners about piping. “Weather causes expansion and contraction of pipes, and if the system isn’t supported correctly the movement will start to tear your roof.”
Additionally, weather plays a huge role in the kind of roof you should consider.
“Start with general conditions in your geographic location and keep in mind that UV exposure eventually destroys everything except silicone caulk,” says Green. “A roof that works in Seattle might not perform as well in Phoenix.”
Green goes on to list the many kinds of flat roofs available today, from asphalt to different single-ply membrane systems to spray foam and liquid applied. Each has their advantages, disadvantages and appropriate uses. “I’m a fan of asphalt,” he says. “It’s durable, handles foot traffic well, and if it’s punctured it can self-heal in hot weather.”
“TPO, or Thermoplastic Polyolefin, is the fastest growing segment of single-ply roofs,” continues Green. “It’s less expensive and considered green-friendly because of the way it’s manufactured.” There is a downside, however. “The TPO they have now is a third-generation product and fairly new. It’s only been around for about five to eight years,” he says. “And heat remains an issue. I would be comfortable with a TPO roof in Spokane, but not in a hot, sunny climate.”
Green speaks to other single-ply options, including a PVC or Polyvinyl Chloride roof (“I’ve seen one with a 30-year warranty.”); EPDM or Ethylene Propylene Diene Terpolymer, which is a synthetic rubber (“EPDM holds up to UV exposure well.”); spray foam and a liquid applied system (“This last one is very high quality but expensive. It’s out of reach for most institutions.”).
Let Your Garden Grow
Vegetated or living (“green”) roofs have become more and more commonplace. “We don’t get as many questions about them as we used to,” reports Crow. Still, many facets need to be examined before deciding on a vegetated roof. “They call them ‘maintenance free,’ but they’re not. If and when they leak there’s a lot of digging up required before you find the problem.”
“I’ve seen vegetated roofs with 15-year warranties,” adds Green. “But they haven’t been around that long. It will be interesting to see how it plays out. I expect there will be expenditures.”
Green does have some helpful hints when considering a vegetated roof. A heavier structure is required to handle the plants, planting material and accumulated water, which adds to initial building costs. He suggests flood-testing the membrane for 24 to 48 hours before planting. Because the inevitable leaks are difficult to find, Green highly recommends installing a vector mapping system on this kind of roof. A low-voltage electrical grid, it measures inconsistencies and pinpoints leaks. “I was suspicious of this technology, so I poked a couple of small holes in the system. The grid found them instantly and I was sold.”
Keep Warm, Not Moldy
While vegetated roofs continue to be popular, the truth is there’s not a lot of LEED points to be found up on the roof. “It’s mostly more paperwork for the roofing contractor, but it won’t give you a big bump like an HVAC system or lighting,” says Crow. She does point out two interesting green roof trends. The first is local ordinances that call for reflective or white roofs, like those found in Chicago. The second is insulation. “Fifteen to 20 years ago, insulation was a hard sell,” she remembers. “Not anymore.”
With insulation comes the opportunity for mold. “Mold needs three things to grow,” says Green. “Food, water and the right temperature. A paper-faced Polyisocianrate insulation material provides the food. Fiberglass-faced Polyisocianrate is more expensive, but won’t allow mold to grow. Even better is Polystyrene. That has no facer and does not take on any water, but it costs even more.”
No matter the insulation choice, Green suggests a hydrothermal analysis with WUFI software. “A building enclosure consultant looks at the whole structure and tells you if you are going to have condensation issues in your roofing,” he says. “It’s a great way to verify a design.”
Routine Roof Care
Less hassle than your routine colonoscopy and just as important, regular roof maintenance will extend the life of your investment. “You wouldn’t expect your fleet of vehicles to go 5,000 miles without changing the oil,” says Michael Rangos, market development manager for education, Tremco Roofing and Building Maintenance. “Owners should be thinking about regular maintenance from day one.”
Regular maintenance is not, “seeing a leak and heading up a ladder with a bucket of sealant,” says Lambert. Instead, he suggests a proactive approach of a twice-yearly visual inspection. “Check the penetrations, edges, curbing, flashing and drains, anyplace where the roof ends or is interrupted. Proper maintenance will extend the life of your roof well beyond the warranty period.”
Oh, and about that warranty — they can be tricky. “A warranty length is no indication of service life,” admits Crow. “Shingles, for instance, often have a lifetime warranty, but no shingle lasts that long. The manufacturer’s warranty is just for the product, not the installation.” So what’s a building owner to do?
“Roofing warranties can be deceiving,” says Green. “You should have an attorney look at them. And consider including a maintenance program.”
This article originally appeared in the March 2014 issue of College Planning & Management.