4 FM quick reads on Roofing
1. How Do Commission Your Roof?
Today's tip, from David Reid and John Wilkins of Gould Evans Architects, is about strategies you should consider when it comes to commissioning your roof.
Most facility managers understand "commissioning" as a strategy that only applies to HVAC systems. But commissioning roof installations is a critical component of a water-tight and energy efficient roof.
Reid and Wilkins suggest three areas to examine when commissioning roofing.
First, look for "weak links" in the integrity of the roofing system, as most of the failures result here. Look at roof terminations, penetrations, flashings at corners, intersections, eaves, curbs and parapets, and drainage systems.
Secondly, especially if you're installing a green roof, but really for any roof, double and triple check that the waterproofing membrane truly is water tight. Perform a leak-detection test appropriate to the type of membrane you've installed. For example, flowing tests flow water continuously over the surface of the waterproofing membrane for a minimum of 24 hours without closing the drains or erecting dams. Electric field vector mapping pinpoints breaches in the roof membrane by tracing the flow of an electric current across the membrane surface.
Thirdly, part of commissioning the roof is creating a plan to protect the membrane until construction is completed and all components - including HVAC, etc. Reid and Wilkins suggest a product called protection board to make sure the roof isn't penetrated or damaged during the rest of the installation or construction process.
2. Roof Replacement Eases Maintenance Woes
I'm Dan Hounsell, editor of Maintenance Solutions magazine. Today's topic is, successful roof replacement. The hailstorm that pummeled the University of Northern Iowa in 2009 did more than uproot hundreds of trees. It also damaged campus buildings and inflicted major damage to the roof of the university's UNI-Dome, a multi-purpose facility on the Cedar Falls, Iowa, campus. The subsequent decision to replace the roof eliminated a long-standing headache for maintenance and operations and brought in a new roofing system that has performed just as intended. The UNI-Dome opened in 1976 and had one unique feature: an inflatable roof. A 1998 storm damaged that roof, which led the installation of a more structured roofing system — a stainless steel, standing-seam system. That roof presented problems throughout its life. "Once we put the standing-seam sheet metal on, it got turned over to me to try to keep it watertight," says Mike Zwanziger, manager of maintenance and operations. "I was working with the local vendor, and every year we'd go up and inspect it. We'd get a report from the UNI-Dome staff about where the leaks were, over what seats, what areas. We were spending, on average, $25,000 a year in an attempt to keep it watertight, and then we'd chase some of these other little leaks throughout the year." But the roof was not simply creating challenges for front-line workers who had to chase the leaks. "We didn't spend a lot of trade man-hours on (roof repairs), but administratively, we spent a lot of time every year trying to trace what was done and what the problems were," Zwanziger says. "It's definitely nice not getting all those calls." The damage from the 2009 storm was a tipping point in the life of the stainless steel standing-seam roof. "Afterwards, when we went up to do an inspection, it looked like someone had taken a baseball bat to the roof, and we had a lot of open seams," Zwanziger says. "At that point, we were able to convince everybody we needed a single-ply roof on it to keep it watertight." The new system also has benefited the maintenance and operations department. "The occupants have been very happy it's not raining inside the dome," he says. "They used to be out there with mops trying to clean up the water or moving people during games so they wouldn't get dripped on. That's probably been the biggest benefit of all."
3. Roofing Technological Advances
I'm Steve Schuster, associate editor of Maintenance Solutions magazine. Today's topic is roofing technological advances.
Technological advances in roofing over the last several years have created an opportunity not only for reduction in energy costs but also for managers to make a positive environmental stewardship contribution.
The significant increases in the use of photovoltaics (PV) in the United States appears to be environmentally friendly, but maintenance and engineering managers must ensure the incorporation of the PV systems does not significantly affect the performance of the roof system.
Research programs that monitor "in place" systems long-term provide a true test to the technological advancements in the roofing industry. It's also important to be aware that not all laboratory test and warranties cover what nature has in store.
Additionally, as technology advances, so do roofing codes.
Although codes have become more stringent in the evolution of the "I" codes (increased wind speeds, etc.) the greatest improvements have been the fine tuning of the critical components, such as attachment of sheet metal components and requirements for detailing.
The actual impact will mean slightly higher costs during construction to provide better detailing and a decrease in costs in annual maintenance and damages related to weather elements. The vast majority of leaks occur at the penetrations and terminations. So the greatest efforts in design, construction, and maintenance should focus on these areas.
Sustainability also plays an integral role. Managers must use time-proven systems properly installed with a proactive maintenance program. Mangers must stay focused on the long-term service life achieved through proper design, construction, and maintenance.
Facility managers have the greatest potential to achieve a successful roof installation by hiring qualified, independent, design professionals to develop a non-proprietary bid package with complete specifications and detailed drawings. The process also requires competitively bidding to a least three pre-qualified contractors. This step should be combined with independent, objective, milestone or full-time inspection services, including final and one year inspections.
4. Three Causes of Moisture Below the Roof Membrane
Today's tip of the day is about three ways moisture can get underneath a single-ply roofing membrane. Because knowing is half the battle, understanding these three common causes can be the first step toward prevention.
First is lack of redundancy. If the seams on single-ply membranes aren't formed correctly, water has a good chance of getting underneath the membrane and leaking into the facility. Single-ply membranes - because they are really only one layer - really rely much more heavily on proper installation than do multi-ply membranes. Ensure that good specifications are written for the installation, and that the installer has plenty of experience installing your particular type of roof.
The second cause of water intrusion is failed flashing. Especially with EPDM single-ply membranes, shrinkage can cause the membrane to pull apart from the vertical flashing and the roof. This unseals the flashing and provides and easy avenue for water. With PVC and TPO membranes, it can be difficult to form flashings around unusual penetrations, like square posts or wide-flange beams. So, again, flashing installation is incredibly important. Make sure your contractor has experience and can show you exactly how he plans to build the flashing and why that construction will be successful at keeping water at bay.
And finally, the third cause of moisture getting underneath single-ply membranes is water vapor diffusion. What exactly does that mean, you may be saying? Basically, water vapor can flow through solid surfaces when the difference in moisture levels, say, in the air outside a building is much greater than inside a building. This happens mostly in temperate climates. That water vapor can then condense underneath the membrane and leak into the building. A solution for this problem is including an appropriate vapor barrier as part of the single-ply roof assembly.
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