Sloped roof incorporates insulation for energy efficiency
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| Photo: Farshid Assari, Beverly Hills, Calif. |
The 2016 Metal Architecture Design Awards judging panel selected Bellswoods, a private residence in Franklin, Tenn., to receive the metal roofing award for its strong articulation, highlevel detail and aesthetics. Steven Ginn, principal at Omaha, Neb.-based Steven Ginn Architects LLC, designed the project. Ginn says the roof is articulated to incorporate rigid foam insulation over interior spaces and omit insulation at two porches on the east and west sides and numerous overhangs. “One reason was to keep the roof edge narrow and slim,” he says. “You’ll see that [the roof] steps up, it bumps up where the heated and cooled spaces are; there’s an edge around it.” Cost was also considered. “The roof’s vented [at the porches and overhangs], but other than that you’re not going to get any benefit from [insulation],” Ginn says.
SLOPING ROOF
It is a simple, sloped, shed-style roof, Ginn says. Shed-style roofs are common on agricultural buildings in the hilly, central Tennessee woodlands. “But the one thing that happens on it that’s interesting is that if you look on the south edge, all the water drains to one point on the roof,” Ginn says. The roof’s narrow edge directs water off it. “We created the slope that you need for the gutters by extending the roof at the middle, and so the roof is shorter at the ends and longer in the middle to facilitate natural drainage,” Ginn says. “That’s what created that shape.”
Nashville, Tenn.-based Don Kennedy Roofing Co. Inc. installed 7,000 square feet of Perth Amboy, N.J.-based Englert Inc.’s Series 1500 1 1/2-inch Architectural Snap-Lock Panel System in Permacolor 3500 Slate Gray for the 5,800-squarefoot project, which was completed in 2016. Don Kennedy Roofing rollformed the Energy Star Cool Roof panels on the job site. Nashville-based Metro Roofing and Metal Supply Inc. fabricated and Don Kennedy Roofing installed metal gutters with Englert’s material. Don Kennedy Roofing also installed Batavia, Ohio-based Gutter Covers International LLC’s Leaf Terminator gutter guards. Franklin-based Welding Unlimited Inc. fabricated and installed steel components to support stainless steel chains in place of downspouts. The chains direct water into an underground cistern covered by a wood platform, where it is stored to water plants and trees on the property. The roof was specified in a light color to avoid the heat island effect, Ginn says. “Really what it’s about, it’s about making it comfortable for the inhabitants with the least amount of power possible,” he says.
FACILITATING EFFICIENCY
Passive solar building design contributes to efficient energy use. Ginn says there are numerous nuanced, bioclimatic responses in the design to promote efficient energy use. The long roof runs east-west and faces south. Long overhangs with porches tucked in underneath them prevent the hot, western sun from penetrating deep into the building, causing heat gain, Ginn says. Porches on the east and west sides provide shade during the morning and afternoon. “The way the roof is designed, it allows the winter sun to penetrate deep into the space, it blocks the summer sun and shades the glass,” he says. “And that’s why you’ll see the lower façade is set back from the upper façade to further facilitate that passive solar design.”
Wind typically flows from the south. “[The house’s orientation and design] allow wind to flow through the windows and then out the clerestory windows on the north side, so you get natural cooling,” Ginn says.
Nashville-based Xelica LLC fabricated and installed operable windows, clerestory windows and exterior doors for the project. All the windows and doors were clad with copper on the exterior.
ORGANIZING WALLS
Ginn describes the design as a box with a skewed cross through it. The house is organized into quadrants by two bisecting, 25-inch-thick, stone walls. One wall is parallel to Old Hillsboro Road, adjacent to the site. “The other wall is perpendicular to the slope of the site, to anchor it on the site and accentuate the views,” Ginn says. “As you walk in, you have a hard wall to frame the view, focus and lead your eye onto the landscape beyond the house.”
The first quadrant is a greeting element and contains the front entrance and courtyard. The second quadrant contains the living room, dining room and kitchen. The third quadrant contains the master bedroom, master closet, master bathroom and east porch. The fourth quadrant is for support functions and has the laundry, powder room, garage and storage closet.
The two stone walls were built with Tennessee Crab Orchard stone. The walls connect the design with the site by referring to fieldstone walls that line both sides of Old Hillsboro Road and other local roadways constructed more than 200 years ago. The stone walls for the house were constructed with recessed mortar to make them appear drystacked, as the fieldstone walls along the roadways were. Ginn says the walls give the roadway a strong dimension. “It really defines them,” he says. “They create a strong presence that I’ve never experienced anywhere else.”
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| Photo: David Massengill, Nashville, Tenn. |
BEFITTING NAME
David and Diane Bell own Bellswoods. David Bell, a semi-retired commodity trading advisor, performed general contracting services for the project. The Bells named their retirement and entertainment home after Bellwood, Neb., a small town founded by Jesse D. Bell, David Bell’s great grandfather, in 1880. Bell grew up in Bellwood and says he shares his grandfather’s passion for the outdoors. Jesse D. Bell planted more than 250 varieties of trees in Nebraska, before he offered the Burlington and Missouri Railroad right-of-way on his land in exchange for tracks and a depot to be built. When Jesse D. Bell submitted the proposed name for the new town to the railroad, Bell’s Woods, the railroad recommended changing it to Bellwood.
More than 17 tree species were used for the Bells Woods project, a number of which Bell accumulated from local trees planned for removal and from trees his great grandfather planted on the family’s farm in Bellwood. For 20 years, Bell collected, milled and dried more than 14,000 board feet of Douglas Fir, Oak, Cherry, Walnut and other species for the project.
Bell says his vision for the project was for it to exude simplistic elegance and remain durable for future generations of his family. “We wanted it to feel like you were outdoors even when indoors; it’s very open,” he says. “I think it draws on my love of the outdoors, love of the trees, the beauty of natural products.
Bellswoods Private Residence, Franklin, Tenn.
Owners: David and Diane Bell, Franklin
Architect: Steven Ginn Architects LLC, Omaha, Neb., stevenginn.com
General contractor: David Bell, Franklin
Installer: Don Kennedy Roofing Co. Inc., Nashville, Tenn., www.donkennedyroofing.com
Fabricator: Metro Roofing and Metal Supply Co. Inc., Nashville, metroroofingsupply.com
Fabricator/steel: Welding Unlimited Inc., Franklin, weldingunlimitedinc.com
Gutter guards: Gutter Covers International LLC, Batavia, Ohio, guttertopper.com
Metal roof panels: Englert Inc., Perth Amboy, N.J., www.englertinc.com
Paint: Tnemec Co. Inc., Kansas City, Mo., www.tnemec.com
Steel cabling/connections: Johnson Marine and Supplies Inc., Ontario, Calif., johnson-marine.com
Windows: Xelica LLC, Nashville, xelica.com