Design Between the Lines

The Walters Residence is slated for LEED Silver certification. Todd Lanning, photographer.

By Georgia Bizios, FAIA, and Katie Wakeford

Bobby and Kristi Walters hired Tonic Design and Tonic Construction, sibling businesses based in Raleigh, North Carolina to help them create what would ultimately be a 4,000 square-foot home for a growing family on a three acre site.  It’s a contemporary home that exceeds their aspirations thanks to green strategies and smart process.

 Projected to receive LEED Silver Certification from the USGBC, the Tonic team pursued energy-efficiency, water conservation, waste reduction, durability, and occupant health and comfort. Features include geothermal heating and cooling, rainwater collection in an underground cistern for irrigation, solar hot water with a tankless backup system, and low maintenance, highly durable materials such as zinc and cedar siding.

Seeking LEED excellence required an extraordinary level of cooperation between the design and construction phases of the project. Tonic is well positioned to do both and achieve the degree of integration that the LEED system advocates.

“We really don’t like the term design/build. It’s too sequential,” says Tonic Principal-in-Charge, Vincent Petrarca. “It suggests you design it, and then build it.” He prefers to call his methodology “construction-led design.”.

The systems of the house and their LEED potential. Image courtesy Tonic.

Nearly 100 participating subcontractors had a hand in the process and that collective body of knowledge and level of participation “served as a valuable editing device,” according to Petrarca. Project designer and construction manager Robby Johnston explains that the drawings for the house were “adequate but not complete,” which allowed the project to improve on the fly.

According to Marshall Dunlap, LEED advisor from the North Carolina Solar Center, the Walters Residence is the first North Carolina house to receive Indoor Air Plus certification, an addendum to the better known Energy Star program. It is a comprehensive and rigorous program addressing indoor air quality issues such as ventilation, filtration, and combustion control. Plus, achieving Indoor Air Plus automatically satisfied the LEED Indoor Air Quality requirements.

Custom shading devices, fabricated by Tonic, will eventually support photovoltaic panels on the roof. Todd Lanning, photographer.

Preliminary utility bills reflect an energy consumption rate that is consistent with a house half the size of the Walters’ house. Todd Lanning, photographer.

Johnston describes the Walters as “initially certification agnostic,” but bottom line benefits demonstrated by lifecycle costing, aided by significant tax breaks and rebates, and in partnership with the positive environmental attributes, convinced the clients of the value of striving for a high performance home.

While the geothermal system seemed expensive up front, generous rebates and long term energy savings sealed the deal.  Handsome custom shading devices, fabricated by Tonic, will eventually support roof top photovoltaic panels for collecting additional renewable energy.

The landscape design is also strongly influenced by the LEED criteria. Walters points out that instead of being a burden, the requirements helped by setting parameters. Wildflowers will skirt the edge of the surrounding woods, a modest lawn of drought tolerant turf will invite outdoor play, and flower beds are strategically located to be enjoyed from the interior. The orthogonal organization of the plan is reflected in the exterior by garden walls, which extend into the landscape and synchronize home and garden.

A composite shadow study indicated the best locations for photovoltaic (pv) panels. Image courtesy Tonic.

Petrarca is optimistic that construction-led design can benefit architectural practices and methods, even if it means accepting additional risks. “Each firm will define what reward means to them, whether that is a commitment to your ideas, keeping more dollars in one firm, or fewer clients.”

“In this strange economy we have been able to sweat in a ditch, tie rebar, and keep our firm together,” he says.

For the homeowners, Tonic’s approach was suited to their idea of a collaborative effort towards a more sustainable home.  “Why wouldn’t you do it? It just makes sense,” says Bobby Walters, who reports that preliminary utility bills reflect energy consumption rate consistent with a house half its size.

“I was in constant contact with the designers and on site every moment possible.  The house is perfectly tailored to what we wanted,” Walters says.

Georgia Bizios, FAIA, LEED AP, is Professor of Architecture, College of Design at North Carolina State University and practices residential architecture.

Katie Wakeford, LEED AP, is an intern architect with the North Carolina State Home Environments Design Initiative and co-editor of Expanding Architecture: Design as Activism (Metropolis Books, 2008).

Walters Residence, Greenville, N.C. | Completed: December, 2009

5,195 square-feet

Owners: Bobby and Kristi Walters
Architectural Firm: Tonic Design
General Contractor:  Tonic Construction
Principal in Charge: Vincent Petrarca
Project Design Manager: Robby Johnston
Construction Manager: Robby Johnston
Design Team:  David Hill, Katherine Hogan, Ted Arendes, David Hammer
Photographer:  Todd Lanning, Gravitation Studios

Selected Consultants:

Steel Stair: McConnell Studios
Engineer: Kaydos-Daniels Engineers
Zinc/Cedar Siding: Richard Thorne
Lighting Design: Living in Lighting
Custom Cabinets: Xylem Cabinets
Rainwater Cisterns: Rainwater Solutions
Landscape Design: NOVO Design
LEED Adviser: North Carolina Solar Center
Acoustical: Audio Advice
Energy Star Adviser and Indoor Air Plus Adviser: Southern Energy Management