Check your Specs
Next to inadequately detailed drawings, architects sign their roofs’ death warrants most frequently through a lack of attention to specifications. Architects frequently—without even realizing it—use specifications that are outdated or don’t meet code, or they reuse boilerplate specifications again and again without tailoring them to the specific needs of a given project.
“Nobody changes their specs,” Warseck says. “They’ll use the same set for 20 years. In the meantime, the whole industry has evolved.” A common jumping-off point for product information is the National Roofing Contractors Association (NRCA) Handbook of Low Slope Roofing Systems. Unfortunately, architects sometimes fail to update their copies. Of the roofing manufacturers listed in a 10-year-old copy, half have gone out of business. Only 65 percent of the products listed are still being produced under a recognizable name. Manufacturers revise their product lines every three years, and they constantly add and delete products from their catalogs and update recommended installation methods. In addition, most municipalities update their building codes every three years as well, meaning specifications have to be updated to stay legitimate. In fact, the third-most-common error made in specifying roofs is that the specifications don’t actually meet code.
Even when specifications are kept up to date, they cannot always be relied upon. “There’s a high reliance on manufacturers’ standards,” Graveline says. “However, there are only so many standards, and there are going to be conditions that aren’t going to be in the book.” As with generic details, standardized specifications are not necessarily going to meet the needs of a given roof, and too often architects reuse manufacturer or in-house specs without customizing them to a specific building. In addition to the differing physical conditions of projects, there are geographic differences in codes and insurance requirements, and different client goals as well. Boilerplate specifications may refer to elements that don’t exist on the roof in question, or, alternately, fail to account for elements that are. And manufacturers’ specifications are generalizations meant for the entire country. But what works in Nevada probably won’t work in Massachusetts.
An equally vexing problem for architects is their reliance on warranties, which are not a substitute for a properly designed, installed, and maintained roof. Warranties are typically written by the manufacturer’s attorneys for the benefit of the manufacturer, and not the architect or their clients. Furthermore, warranties are not the same as insurance. In fact, they rarely cover the items damaged by water intrusion that are the most costly to replace: incidentals such as furniture, equipment, interior finishes, and electronics. What they do instead is lull architects into a false sense of security.
Preventing roof damage may seem beyond the control of architects, and in some ways that is true. There is little a designer can do to stop blue ice, meteorites, or falling trees from wreaking havoc on their projects. However, there is a more pervasive and insidious foe to the integrity of a roof: mechanical equipment. Never mind the flashing details and penetrations that these systems require, the real threat are the men and women who service them. “We’re putting more and more stuff on our roofs,” Graveline says. “If it’s not protected with adequate walkways and cover boards beneath the membrane, a roof can get damaged because service people just treat it as a work surface. They drop tools, they drop covers, they roll carts. Those things can result in damage. On top of doing the damage, they also don’t report it, so by the time you notice the problem you have a big issue on your hands.”
Architects can do their part to prevent this kind of damage by placing walkways where they will actually be used, as opposed to either not at all or where they look pretty. That means placing walkways in a direct line, the shortest distance from roof access to mechanical units. No service person is going to follow a course of 90-degree turns to replace a filter or squeegee a solar panel.
There is also a payoff to be had in educating clients on how to properly maintain their roofs once they are installed. Since the architects are familiar with the materials specified and installed, they can pass on this information to help avoid roof failures due to improper maintenance or cleaning; if enough dirt and debris builds up on a roof surface, the owners can find themselves with an unintended rooftop garden on their hands, and the root systems can cause damage to roofing materials. Roofs do fail due to poor maintenance, and when that happens, litigators look to the architect. So a little shared knowledge can help to avoid headaches later on.
What To Do
The fact of the matter is that no roof, no matter how well designed or installed, will ever last as long as the rest of the building. It’s simple math: Most roofs have an average life span of 20 years, most building are designed to last at least 50. Sooner or later someone will have to re-roof the building, so plan for it.
There are steps that architects can take to ensure that a roof lasts as long as it is supposed to. Since most roofing problems do stem from poor installation, it behooves the designer to investigate the quality of the local labor pool and specify systems that fit their abilities. Architects should also only specify materials that are actually necessary and that include warranties favoring the owner; and they should use current products and customize boilerplate specifications to meet the project in question; they should customize manufacturers’ details and make sure to detail every termination and penetration. And perhaps most importantly, architects must remember to think in three dimensions. Even though most people won’t see the roof, its design deserves as much attention as the rest of the building.