Putting the Right Roof Over Your Head
- By Julie Sturgeon
- June 1st, 2004
If a regular roof costs $2 per sq. ft. and an energy-efficient one costs you $3.50, but returns a 20 percent energy savings - which one should your campus choose? When Stephen Roades, vice president of Burke Industries in San Jose, Calif., does the math, the answer is a no-brainer.
Yet he admits his high-end single-ply product remains a tough sell in this market. "Look at our state - we're broke! Upfront dollars sometimes mean a lot more than long-term dollars because putting roof itself doesn't increase the value of the building," Roades says honestly.
The same winds blow in Carlisle, Pennsylvania, where EPM marketing manager Mike DuCharme at Carlisle SynTek, also sees his fair share of price-conscious folks. "They don't look down the road at how the roof will be used and impacted over time," he points out. "You have to design for those factors. In many cases, in the effort to get the best value, we're not getting the best roof system."
Life cycle costing is a relatively new strategy in the roofing industry - meaning savvy administrators first began reaching for their calculators in the mid- to late-80s, says Roades. While that commitment has gained momentum, it's still a slow real-time process when most installed roofs last 20 years before the topic rears its head again.
Any construction expert worth his salt will analyze roof plans beyond merely material and shape. The insulation, its interaction with the membrane, the fasteners - all impact the final life cycle costs, so looking at only one component like R value or reflectivity can skew your actual results. But it is important to understand your basic choices from the start, assures James R. Kirby, AIA, senior technical director of the National Roofing Contractors Association (NCRA), headquartered in Rosemont, Ill.
Types of Low-Slope Roofing
Built-up roofs: Layers of asphalt and ply felts built up on the roof, typically with some kind of pea gravel on top for protection against ultraviolet rays, mechanical damage, and fire resistance. After 100 years in existence, they're considered the industry backbone. Contractors install it in three-ft. wide, 35-ft.-long rolls, so the final esthetics show seams.
Modified bitumen: Essentially a pre-manufactured built-up roof, also asphalt-based with chemical modifiers to make the overall product more elastic and puncture-resistant. A majority are torched in place or put down in coal adhesive. Single-ply systems: Thinner roofing materials affectionately known as EPDM, TPO and PVC.
Where a built-up roof is typically 3/16ths of an in. thick, these acronym versions are closer to 1/8th of an in. (although manufacturers now produce some sheets as thick as 45 to 90 milliliters). The more layers, the longer the service life - which only makes sense when you realize that dropping a screw and stepping on it likely punctures the thin membrane - jargon for "spring a leak" - unless you force the foreign object to penetrate several layers. On the other hand, this system offers a wider color range from white to a darker, grayish black. Those who do sprinkle rock over single-ply can choose the larger 1.5-in. rounded river rocks rather than gravel for an esthetic statement.
Spray polyurethane foam-based (SPF) systems: Basically this is a sprayed-in-place insulation. Contractors spray three to four in. thick, then install a waterproof coating on top. The esthetics are different, as this produces no seams and no mechanical fasteners.
Metal panels: These copper or zinc sheets work best on a structure with barrel-vaulted roof that needs a high-profile appearance.
The Steep-Slope Category
Roofers begin throwing out asphalt shingles, clay, concrete tiles and slate choices - more expensive options that can endure the elements anywhere from 60 to 80 years and never show their age, says Kirby.
Is It Worth It?
The bottom-line question college administrators need to answer while sifting through these product samples, says Roades, is "How can this roof pay me back?" For instance, any time you can reduce the cost of cooling a building, which is substantially more money in most cases than heating it, that roof is worth its purchase price in his experience. So it behooves leaders in Tucson, Ariz. to lean toward a white reflective roof with added insulation, which would lower the cooling costs by approximately 30 percent. It's that kind of money that enticed California to enact a law saying that all reroofing and new construction in the Golden State from 2005 forward will include an Energy Star cool roof.
But use your head rather than make a knee-jerk reaction. "If you're in Minnesota, where they air-condition three months a year and the rest of the time want to absorb some solar heat, a white roof may not be the right thing to do," comments Kirby. However, the other categories offer a more national appeal, he says. That's why college administrators are rarely required to sacrifice style for this life cycle costing approach - some materials merely require more attention and planning to squeeze the most efficiency from.
DuCharme relies on software to pinpoint operating costs and weigh energy R values for a given location. "It gets complicated because there's a payback analysis," he says. "Do you spec R 40 or R 25? Certainly more is better but there's always a point of diminishing returns. Luckily, I know of at least four calculators out there that can specifically address this."
The next concern is to seek ways to extend your roof system's lifespan. For instance, a 60-milliliter membrane uses a seam that's twice as wide as the 45-milliliter choice, giving the former a longer life expectancy "Typically, then, the manufacturer warranties it for that longer life span, so the operating costs really go onto the manufacturer," says DuCharme. Remember: Some manufacturers now dangle 30-year warrantees with their roofing systems, which could spread the larger initial cost very attractively over that period.
Just be sure to crunch the numbers building by building. The 90-milliliter thick roof with beefed up insulation and separate high-wind speed, hail and puncture warrantees maybe be the best solution for a high-rise structure or the computer lab. Low-risk areas like the maintenance and grounds building can probably get by with a less involved (and expensive) option. Wasting money is wasting money, no matter how pure your intentions.
"As more is known about lifecycle costing for roofs, it will definitely open some eyes and minds of the people holding the purse strings at colleges and universities," assures Roades. "Like all of us, they want to save money anywhere they can. If the roof is saving money - well, there you have it."