by Russell Boniface
Associate Editor

How do you . . . take advantage of site topography to create a sustainable park destination center?

Summary: The Blue Ridge Parkway, arguably one of the nation’s most beautiful roads, winds for 469 miles through the Appalachian ranges of Virginia, North Carolina, and Tennessee. Lord, Aeck & Sargent worked with the National Park Service on the sustainable design for the two-story, 12,000-square-foot Blue Ridge Parkway Destination Center, located along the parkway and adjacent to its headquarters at Hemphill Knob near Asheville, N.C. The $9.8 million building, cut into a hillside, uses site topography to integrate passive solar strategies, capture views of the mountains, and create a “tree house” effect for the structure. The project is seeking LEED® Gold certification for sustainable elements that include vented trombe walls and a green roof of native plants. A ribbon-cutting ceremony will be held on April 14, and the Center will open officially April 15.

Lord, Aeck & Sargent ‘s John Starr, AIA, project principal, and Joshua Gassman, associate and project manager and project architect, worked on the Blue Ridge Parkway Destination Center. ”The building and site become as much a part of the exhibit and teaching mission as the exhibit,” Starr says.

The National Park Service helped identify the site and refine its standard visitor center design. “The site was chosen because it was adjacent to the headquarters, close to the parkway, and offered views of the parkway,” Starr explains. Throughout the center project, the firm carried the idea of integrating site topography with trombe walls, a green sloping roof, sustainable features, and exhibits.

Trombe walls
“The best example of integration was the use of the trombe walls,” Gassman explains. “The climate was suited for passive solar, but, for a trombe wall to work ideally, you want it facing due south. Because of the steep site and an existing entrance road, we wanted to shift the building 30 degrees from due south for it to lay into the land. To maximize the southern exposure, then, we broke the southern façade into short pieces to form a series of trombe walls and rotated them to face south to capture the sun and heat the building. The trombe walls, back to the theme of integration, also function on the inside as exhibit points. They are also the primary lateral forces for resistance and integrate with mechanical systems to distribute air and heat the exhibit floor.”

“As we rotated the trombe walls, we created window views out to the parkway itself,” Starr adds. ”One aspect of the building is that it captures these views of the parkway, and the nature and culture around the parkway, just like the parkway itself was designed to do.”

Treehouse experience
The idea that the site drops down—and that the Blue Ridge Parkway is predominately explored by car—gave birth to treehouse idea, says Gassman. “To the west there is a vista view of mountain peaks. We wanted to offer a contrasting, intimate experience with the woods. The five-foot, floor-to-ceiling trombe wall windows give visitors views with the parkway beyond. We call it the treehouse experience. Visitors enter at grade at the west end of the building, but the site drops away, so the view from the interior ends up 15 feet off the natural grade, and you’re really on the second story. It’s like being in a treehouse in the middle of the woods.”

Sustainable strategies, sloping roof tie into the Blue Ridge character
“We were originally targeting LEED Silver, but our office doesn’t get caught up in going after specific credits,” says Gassman. “We were trying to create a sustainable building by making the right decisions. By the time we were through, we were on target for LEED Gold.” In addition to the trombe wall and the radiant heated flooring, the Blue Ridge Parkway Destination Center has a 10,000-square-foot sloping roof with native, drought tolerant plants. Says Starr, “It provides a thermal buffer within the building.” A cistern captures rainwater as it comes off the roof to irrigate the site and roof.

Both Gassman and Starr note that the sloping, green roof and use of cedar siding on the arrival side of the building tie into the familiar National Park Service look and surroundings. And, it catches visitors’ eyes as they drive in. Explains Gassman: “They approach the building from the back, and from that perspective the roof is split into the raised gable end, which is on the south side of the building, and a lower flat piece on the north. The lower flat piece is actually eight feet off the road and at eye level, so they drive in and see the sloping planted roof. It relates nicely to the mountains beyond.”

Adds Starr: “The parkway has a strong vernacular, and the Park Service is keen to keep their buildings in line with that vernacular. But in looking at this project, they were interested in letting the building show off its sustainable elements. The roof is an example of where we integrated the two ideas. They liked the idea of the sloping green roof because it has a form consistent with other Parkway buildings.”

Sustainable elements also include fly-ash recycled concrete and a curtain wall of recycled aluminum. Inside, the curtain wall maximizes light, while light shelves bounce light deeper into the exhibit hall. Photo sensors dim lights when there is adequate natural light. A glu-lam beam structure completes the traditional heavy timber look. The building also employs a dual-wheel energy recovery unit. “Exhaust and intake run through the unit, and two wheels spin in opposite directions,” says Gassman. “The net effect of that is air from the outside in winter is captured and pre-heated by the energy in the exhaust stream, reducing the amount of energy required to heat the building. The process in the summer works in reverse, cooling the intake air.” Rounding out the building’s green design elements are a cistern to direct water from the parking lots into a bioswale that filters it into the groundwater and, on the interior, low-VOC paint and sealants.