Enhancing Roofing Performance
- By Thomas C. Dolan
- March 1st, 2006
School facilities, by their nature, have the tendency to present a multitude of problems that demand to be dealt with immediately. The problems assoc¬iated with roofing, however, are often thought of as long-range. They tend to be neglected until they reach a point where they must be faced.
Denver Public Schools in Colorado faced this type of situation.We’re understaffed and have only three roofers for 165 buildings, said Director of Operations and Maintenance Trena Jones.With an average two-in. snow, we might get 40 to 60 leaks.
Jones said they have managed to address the problem without adding any more roofers by getting bond issues passed to fund having roofs replaced and older ones repaired. Jones said the trick is to have the procedures in place to both get the bond issues passed and make sure the money needed to get the job done is incorporated into the bond issue.
Each time we prepare for a roofing bond referendum, we go out and assess every roof based on its age, condition and defects. Based on that information, we prioritize what goes into the bond, Jones said. This information is also put into what we call a Facility Condition Index, which is really val¬uable even if we don’t have a bond in process because it helps us to plan future needs.
When a bond referendum is upcoming, said Jones, this index goes before a citizen committee whose function it is to approve, deny or modify the bond request. The roofs are graded on a 10-to-one scale — from very good to lousy. The committee looks at the index, sees the actual data we used to back up our requests, and they know we are asking for funds actually needed, not just what we might like to have on hand.
Kenneth Montoya, supervisor/foreman for the protective coating shop, said the district is fortunate to have three very qualified roofers. But, there is much to do and mainten¬ance routines tend to bog them down, in terms of their main tasks of installing and repairing roofs. To help out in this area, just last year, we adds a preventive maintenance shop with eight employees who, working from a pre-assigned schedule, maintain not only the roofs, but the other aspects of the buildings as well, Montoya said. This takes the burden off of the roofers and the adds focus on maintenance, of course, helps preserve the roofs.
The index program was established seven years ago. Now, reports Jones, instead of getting calls for 40 to 60 leaks because of an average two-in. snowfall, they get maybe five calls. We’ve probably had 60 percent of the buildings reroofed in the past seven years, Jones said. The average roof won’t last more than 25 years. It would be nice to be on a 20-year rotation, but financially, that’s not going to happen, she adds We’re in good shape now, but if we fail to get a bond passed for another 10 years, we’ll be in terrible shape again. But, of course, we’re going to do everything we can to keep that from happening, she said.
Roofer David Hunt said that since some roofs are required to have specific slopes, they also require higher outside walls. With slopes running 70 to 80 ft., there can be the need for four-ft. outside walls, with 12 in. on the high side. This can cause a lot of difficulties, Hunt said, because these walls can be difficult to maintain. Some architects just see the aesthetics and don’t know how to deal adequately with the thickness of the taper and the slopes — others are on top of it. Hunt recommends choosing an architect who is savvy in these matters, and then, submit the drawings to a planning review. Once we started doing that, we’ve had fewer problems.
Hunt said the district has some flat tile roofs, concrete-panel-wall buildings and new brick buildings that are amenable to clear coatings. He generally prefers built-up rather than EPDM roofs because, a good built-up roof will last 40 years, and the EPDM generally lasts about 20 years. You can maintain the built-up roofs longer. But once the rubber glue goes on the EPDM roofs, there’s no way to maintain them. They go all at once. Then, you have to strip them down and start over. Hunt acknowledges that finan¬cial considerations come into play — he said EPDM roofs cost $200 per sq. ft. less than built-up roofs.
Michael DuCharme, director of Product Marketing for Carlisle SynTec, Inc., located in Carlisle, Pa., said that there can be environmental considerations relating to EPDM roofing, which has been around since the 1960s, especially with the older types. EPDM is basically rubber. It can’t be heat welded. It has to be glued down for installation. The glue is what creates environmental problems. One solution, DuCharme said, is a splice tape that is being installed on the sheet at the factory, so that you’re eliminating the use of hazardous materials and saving labor.
A more recent roofing option is TPO — a thermoplastic material — which can be heat welded. This is more of an environ¬mentally friendly, green roofing system, which is a plus in places like California, where the regulations are more strin¬gent, DuCharme said.
One other trend that seems to be helping eliminate leaks, DuCharme adds, is that many manufacturers are attempting to prefabricate details, such as corners and flashings, which are usually the main points for leakage.
Recently, there has been a big emphasis on reflec¬tive, primarily white, roofing systems, said Fred Sitter, marketing director for Duro-Last Roofing, Inc., in Saginaw, Mich. These systems have a considerable impact on the savings of cooling and energy costs. Yet, there are also other environmental costs to be considered Sitter said, from how much energy it takes to manufacture a roof, to how well it can be recycled into useful material at the end of its original use. Roofs that have to be torn off must be disposed of in landfills, Sitter said. A many-layered roof will result in a lot of material. But some lightweight materials don’t need to be torn off. They can stay in place and have a new system built over them.
In some parts of the country, Sitter continues, especially dry climates, rain water is harvested. In those areas subject to drought, or where there is difficulty in getting to under¬ground water, rainwater is collected in underground cisterns. Sometimes this water is also used as an energy source, drawing heat from the ground and pumped up through the school pipes. There are many technologies, both experimental and well developed, attempting to recycle rainwater he said. But, the basic concept is nothing new. Jones reports that the Denver system has a single catch basin on one roof that has been around since the 1920s that collects the water that backs up on the roof.
So what is the smartest way to make decision about school roofs? Sitter recommends looking at the true life-cycle costs of the roof, long-term savings and short-term costs, as well as maintenance costs. The roof’s primary function is to withstand water, he said. Determine how well it is engineered to withstand all of the climate changes in your region — rain, frost cycles, cold and hot temperatures — and remember to factor in other conditions, such as the possibility of hurricanes or tornadoes.
DuCharme suggests looking to the manufacturer’s track record — how long he’s been around, his financial viability, how well he trains local contractors in installing his system, and warranties. DuCharme said that most companies offer comprehensive warranties. It’s almost like the insurance industry, he said. “They offer variations on the same theme.
Keep in mind that some problems are not going to be covered by warranties. Sometimes, the problems in roofing don’t result from the materials, most of which are well made and are, themselves, covered by the warranties. Problems can result from there being too many materials layered on the roof, the mixing of different systems that may not be complementary or, maybe, the problems result from the installation. The main thing is to make sure that if you buy a roof promised to last 20, 30 or 40 years, you get in writing just who is responsible for keeping that promise.