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A Study in Light and Shadow

A private residence in Memphis aims for zero energy/zero carbon

Civitas 03

The tension between architectural expression and building performance is never so great as in a structure that pushes the boundaries of sustainability. Civitas, the private residence on the Mississippi River in Memphis, Tenn., achieves the highest performance standards and does so with the fullest and most sophisticated sense of architectural expression.

“They nailed it in so many ways,” says judge Rick Harlan Schneider, AIA, APA, LEED AP, ISTUDIOArchitects, Washington, D.C. “This is a LEED Platinum home, carbon neutral and adheres to the AIA 2030 challenge. Those are just the metrics. The fact that it is artful and beautiful takes it up a notch.”

Civitas is the residence for the Memphis-based archimania principal, Barry Yoakum, FAIA, who designed and constructed the house. The firm used the design process as an opportunity for experimentation. Judge David Dowell, AIA, partner, el dorado Inc., Kansas City, Mo., says, “Single-family residences are great and important testing grounds for ideas.”

Photos: archimania

“How do you bring design from pure architecture to pure performance and not let either hurt the other, but reinforce each other?” asks Yoakum. “That was our goal from the start … We really didn’t want people to know it was sustainable. It was just a good piece of architecture. It was a good place to live.”

The 2,798-square-foot home sits on a corner lot in an established neighborhood next to the river. The upper floor has clear views of downtown Memphis. Its structure emphasizes the contrast between the public and private areas of a residence. “It’s on an elevated plinth,” says Will Randolph, AIA, archimania, “with an open pavilion downstairs for living with the community and a private box upstairs. Living, kitchen, dining, community spaces are open. Bedrooms are for privacy and retreat.”

Expression and Performance

That describes the basic form of the building, but if you stopped there, it would just be a great piece of architecture, nearly sculptural. It’s through the expression and performance of the building materials that the home becomes much greater than its parts.

“It’s about light and shadow,” says Yoakum. “It really became about how you take a material and express it, and it doesn’t matter what the color is. It’s kind of like an Ansel Adams photograph. How do you take nature and make it better by distilling it down to shade and shadow?”

In late afternoon, the upper form can disappear into the sky, but during the day, when the sun is high, the light catches the 1/8-inch folds on the vertical metal panels and casts shadows that are 4 to 5 inches long. Windows, recessed 12 inches, provide shade at the height of summer, and allow full sunlight in the winter.

That beauty, organically inspired, has a high-tech performance attribute that makes the house even more notable. Among its sustainable attributes are a solar array on the roof with a battery back-up, geothermal heat pumps with radiant floor heating, a water cistern that collects roof water and can hold 10,000 gallons. “This house could be completely off the grid,” says Yoakum.

Perhaps the most inspired performance element of the house is the dual-metal skin attached to the structural insulated panels on the upper form. The south façade features a 3-inch void between the skins, and the roof funnels water into the void, which cools the house and allows cooler air to circulate against the interior skin. “It’s basically a downspout the entire length of the southern side of the house,” says Randolph. “The roof turns down into the wall material, and there’s a second layer of metal furred off of that. Normally it creates an air cavity all day long, but when we get rain or moisture, it really starts to change the environment in that cavity.” Yoakum describes it as a big refrigerator on top of the house.

The inspiration for that design comes from an unlikely source: the Apollo space suit, which had 21 layers and was designed to protect humans from the most extreme environments even though it was incredibly thin.

In that context, recycled aluminum panels were the perfect choice. “The reason we selected aluminum,” says Yoakum, “even though it has high carbon, is that it will last forever. It will never corrode.” Petersen Aluminum Corp., Elk Grove Village, Ill., supplied the panels, and Ralph Jones Sheet Metal Inc., Arlington, Tenn., fabricated and installed them.

The result is a LEED Platinum home that is poised to be the first home in North America to be certified as zero energy/zero carbon by the International Living Future Institute. It also achieves the goals of the AIA 2030 Challenge a decade early.

Privacy and Community

The upper volume may draw the eye, but it is the open pavilion on the first floor connects the house with the community. The floor plan includes an outdoor fireplace between the two living areas. Full-height glass breaks down the barrier between the indoors and outdoors, and the openness seems to make the upper form float above it.

Surrounding the pavilion are movable, aluminum expanded-metal scrims. Depending on the need for shade or privacy, the scrims can be positioned around the outside, creating a private exterior space outside the glass and preventing prying eyes if the homeowners want it. Yoakum enjoys the opportunity to change his home, and says the scrims are simple to move. The decision to make them manually operated was purposeful to give the residents a more personal engagement with the house. “The scrim system is kind of commonsensical,” says Yoakum. “It’s tunable, and you get to modify something on your house. It's manually tunable. It’s tactile. It’s not about pushing buttons.”

The scrims also have a huge effect on the sense of light inside and surrounding the house.

“The expanded metal panels for being a relatively raw, natural material are beautiful on their own,” says Randolph. “But when they get animated by the sun and you get ripples of light falling in different ways down that expanded metal, and then they cast these really dynamic shadows on the ground, it’s just a delight to be in that in-between space around the house.”