metalmag Architectural Awards Winner: Roofs

Working as a team throughout the design and construction process is a common strategy on green-building projects. When the owner, architect, mechanical engineer, general contractor, landscape architect and others are involved from the beginning of a project, synergies between systems often are recognized that otherwise would not have been contemplated. For example, a landscape water feature can be created with graywater from a building’s sinks or laundry facilities. The water also can be circulated through the building’s radiant-floor heating-and-cooling system. These techniques can save thousands of gallons of potable water, hundreds of kilowatts of energy and the energy production’s corresponding carbon-dioxide emissions, and a great deal of money.

Credit: THE KUBALA WASHATKO ARCHITECTS INC./MARK F. HEFFRON

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As would be expected from a building commissioned by the foundation of a famous conservationist, the Aldo Leopold Legacy Center, Baraboo, Wis., took advantage of integrated-design synergies and today is the world’s highest-scoring LEED Platinum building, having earned 61 points out of a possible 69 under the LEED for New Construction green-building rating system. (LEED is a program of the U.S. Green Building Council, Washington, D.C.)

The project employs several innovative green-building strategies. For example, the three buildings that make up the center are constructed of wood made available by thinning the Leopold Memorial Reserve’s 1,500 acres (607 hectares). Extensive studies showed the reserve’s trees, which were planted by the Leopold family in the 1930s and 1940s, were starving for space and light and therefore at risk for disease, insect infestation and fire. Although Joel Krueger, architect with The Kubala Washatko Architects Inc., Cedarburg, Wis., and project manager for the center, says this strategy was like “putting the cart before the horse,” the design team developed a spreadsheet of what types and amounts of wood were available from thinning the forest and was able to apply the wood to the buildings.

The recognition from USGBC’s program is not the only praise the project has garnered. Among several awards, the Aldo Leopold Legacy Center recently won first place in the Roofs category of metalmag’s 2007 Architectural Awards program. The Galvalume Plus metal roof caught the attention of the judges for contributing to the structure in multiple ways, including hosting a photovoltaic system and solar hot-water system, as well as guiding rainwater to an on-site rain garden.

“The Aldo Leopold Legacy Center’s

roof blends the beauty and longevity of a standing-seam metal roof with the functionality of renewable energy from a photovoltaic system. The roof has clean and crisp lines that integrate nicely with the PV modules mounted to the standing seams of the roof. The other feature that impressed me was the spectacular way in which the rainwater-harvesting benefit of the metal roof was combined into an architecturally designed cascading array,” says Scott Kriner, LEED AP, president of Green Metal Consulting, Macungie, Pa., and one of the jury members for the 2007 metalmag Architectural Awards program.

Must Be Metal

From the time The Kubala Washatko Architects was hired for the project’s design, there was no doubt in Krueger’s mind that he would specify metal for the roof system. In the last 10 years, he has chosen standing-seam Galvalume metal roofs for three other nature centers and believes in the product. “One of our sustainable goals is to design buildings that will last 100 years or more,” he says. “That starts with the structure and how you cover the structure and what you choose for materials. We’re just huge fans of the Galvalume metal roof. The standing-seam-type roof is a longlasting system. We also design roof slopes that will help lengthen the life of the roof.”

The roof’s slope also helps bring natural daylight into the Aldo Leopold Legacy Center’s buildings. This reduces the need for electric lights, lowering energy consumption and costs associated with operations. “We’re always taking advantage of natural daylight, so we do pitched roofs that allow clerestories to bring in light and ventilation,” Krueger notes. The three buildings required 16,200 square feet (1505 m2) of prefinished Galvalume Plus, 24-gauge panels that are 16-inches (406-mm) wide with a 2-inch- (51-mm-) high mechanically seamed rib. The prefabricated panels were shipped to the site in lengths up to 40 feet (12 m) and installed by four crew members from Nations Roof North LLC, Waukesha, Wis., over a structural-insulated-panel deck. (A SIP typically consists of a rigid-foamplastic- insulation core sandwiched between two structural skins of oriented strand board.) The core of the SIP deck provides insulation with an R-48 value for the roof. An ice and water barrier was placed over the deck. Clips were attached 24 inches (610 mm) on center; fasteners go through the insulation into the SIP, providing wind-uplift resistance.

According to John Anzivino, principal of Saturn Wisconsin, a manufacturer’s representative for the metal roofing product based in Saturn, Wis., the Galvalume Plus roof, which is warranted for 20 years non-rustthrough, is a medium gray that only can be duplicated by zinc at a higher cost. Typically a Galvalume finish serves as a base, or primer, on a Kynar-coated metal roof. “In a case where a customer, like Joel, decides to use a Galvalume Plus, the Plus means there’s a clear acrylic coating put on the material as a final stage to keep everything uniform,” Anzivino points out. “Galvalume and galvanized products in the past didn’t have a lot of consistency from the steel mills because they were designed to be a substrate, not a finish. With the advent of Galvalume Plus, the acrylic coating makes it easier to work with and consistent when the product is built. The acrylic coatings do not have any pigments in them, so they slowly weather off and you end up with an architectural mottled gray panel that the industry likes.”

In addition to providing the roof, Galvalume Plus flat sheet was custom bent for half-round gutters, downspouts and other trim by Nations Roof North’s sophisticated metal shop. Nations Roof North also custom fabricated a chimney cap from the material.

There’s More to Metal // The standing- seam roof provided an ideal platform for non-penetrating attachment of 2,800 square feet (260 m2) of photovoltaic panels, which are south facing at a 4:12 (18-degree) pitch. The angle of the PV panels allows air to circulate behind and cool the PV, which helps the cells run more efficiently. As much as 0.5 percent of output can be lost for every degree Celsius the PV are above 77 F (25 C).

The 39-kilowatt PV system is one of the great success stories of the project, Krueger notes. Although heavy snowfalls in Wisconsin last winter slowed energy production, the panels produced more electricity than the building consumed from the time the center opened in May 2007 until December 2007. The building’s performance, including that of the PV, is being monitored, and Krueger and his team expect the panels to produce comparable amounts of energy—if not more—this year.

Green-building technologies, such as PV, are becoming more mainstream because they make economic sense to building owners, according to Gregg Tucek, project manager for The Boldt Co., Appleton, Wis. “When we were in design, this was going to be the largest array in the state. By the time we got done building, it was the second largest. These technologies are gaining momentum.”

Another technology gaining momentum that was included in the Aldo Leopold Legacy Center is solar hot-water heating. A collector system made of evacuated glass tubes is mounted to the roof and transfers heat through the collectors into a manifold that heats a recycled-water system. The energy then is transferred into a hot-water tank. Like the PV system, the collectors must face the sun without shadow or shade for the solar-hot-water system to work efficiently.

Tucek never had budgeted for a greenbuilding project before but was assisted by others on the project who had experience. “As the construction manager, we have to be knowledgeable about everything but can’t be experts on it all,” he says. “We relied on subcontractors, especially about something as custom as the PV or domestic- hot-water system.”

The roof also acts as a rainwater-capture system. The custom half-round gutters are sloped to a downspout and funneled to a Galvalume metal trough inside a long, stepped, field-stone wall that hides one cistern. A small solar pump recirculates 50 gallons (189 L) of water through the trough. The trickling sound of the water masks noise from cars on a highway more than 4 miles (6 km) away.

“Any time the sun is out, the water feature is running,” Krueger says. “In a big rain event, all the roof water runs through the trough and to a depression we’ve created on the site, which is essentially a rain garden on an existing low spot.”

Although the trough and field-stone wall, which consists of recycled stones pulled from an old building, are appealing features of the building, they created a challenge for Nations Roof North’s sheet-metal workers. “We field measured and made the trough in the shop,” explains Dave Weiss, Nations Roof North’s president. “It had a lot of irregular areas, and we had to taper a lot of pieces.”

Fitting Remembrance

The Aldo Leopold Legacy Center is standing on the site where Leopold died fighting a brush fire in 1948. Its beautiful roof slowly is developing a dusty-gray patina that will make it look even more appropriate against the natural wood finish of the buildings.

Leopold likely would approve of the center bearing his name, not only because of its sustainable features, but also because it brought together a team of people and exposed them to ways in which they can perform their jobs in a more environmentally friendly manner.

Krueger explains: “This team worked so hard together to solve so many problems. Imagine bringing in a carpenter and telling him we’re going to build a building from trees we’re cutting down on the site. It just isn’t done anymore. We ended up with a team that didn’t want to leave when the project was done because they had so much fun building this building. So the same things that were challenging for us turned out to be the most meaningful and fun.”