When deciding to design and build new office space, BuildSense, a full-service architectural and contracting firm in Durham, N.C., knew that the building needed to represent its business and the work it does. “We wanted the building to represent us,” says Erik Van Mehlman, AIA, CGP, partner of BuildSense. “It had to be well designed and well built. We were going to walk the walk because we always talk the talk.”
Around since 1999, the 10-person company simply believes in building smarter and building better, and has always believed in building buildings the right way. Mehlman says that they’ve always been environmentally responsible and conscientious builders, well before becoming known as the green guys.
Mehlman, along with partner Randall Lanou, LEED AP, MCGP, teamed up with the owners of Clear-Vue Glass to purchase an existing building downtown. A former farm equipment and auto repair building, the original 6,000-square-foot, one-story 1940s masonry warehouse was renovated and converted into a 12,000-square-foot, two-story, energy-efficient office and retail facility in the last stages of LEED Platinum certification. The first floor houses Clear-Vue’s showroom and workshop, in addition to a tenant storefront, while the second floor addition is home to BuildSense and additional office tenant space.
“We wanted something which respected the area but was also new and different,” Mehlman notes. “We wanted it to maintain a warehouse aesthetic, but also to say, ‘I’m different. I’m a new era of building.'”
Smart Design
Before beginning work on the new building, Mehlman and Lanou met with the entire staff to develop priority lists. As the staff went through the lists, it became evident that the building needed to be representative of the company and its work of designing and building sustainable and energy-efficient homes.
The firm preserved the original masonry shell and steel structure of the warehouse, while creating a super-efficient thermal envelope. The new roof utilizes CF42R insulated standing seam metal roof panels with a 6-inch urethane core from Metl-Span, Lewisville, Texas. The 24-gauge outer panel in Polar White reflects sunlight, greatly reducing cooling loads over the summer, while the 26-gauge inside panel in Snow White provides a reflective ceiling above the open web steel joists, making the electrical lighting more efficient. Usually used in refrigerated buildings, the R-42 panel has a finished surface on both sides, allowing for easy installation.
The second-story addition features a non-structural exterior wall system wrapped around a structural steel frame, Mehlman explains. The walls have 1-inch continuous exterior insulation along with 5 1/2 inches of open-cell spray foam to provide a thermal barrier. Additionally, the exterior is clad with narrow corrugated metal panels from Union Corrugating Co., Fayetteville, N.C.
On the first floor, stud walls were built out 1-inch from the face of the existing 12-inch masonry walls, and closed-cell foam was sprayed in between. “By building the stud walls 1-inch off of the exterior face of the masonry, we have a continuous 1-inch area of closed-cell foam, plus the extra 3 1/2 inches that’s in the stud wall,” Mehlman explains. “We have essentially 4 1/2 inches total, but there’s 1-inch that’s a complete vapor barrier, keeping any moisture from moving into our building.”
With great views of downtown Durham, the building gets a lot of natural light. In certain areas, such as a rear hallway without any windows, Solatubes from Solatube International Inc., Vista, Calif., bring in natural light. “We have a thing about comfort and natural light,” Mehlman says. “I think everybody is really happy and comfortable in the spaces.”
The building also has very efficient residential air handling HVAC systems for each tenant space along with fresh-air heat recovery ventilators that are occupancy sensitive, providing a filtered circulation of fresh air coming in and out of the building. Additionally, the building has a 3,200-gallon cistern that uses reclaimed roof water for landscaping and toilet flushing, as well as a compressed natural gas (CNG) fuel station for BuildSense’s CNG vehicles.
Clean Energy Generation
A grant from the North Carolina Green Business Fund helped in executing the energy-efficient LEED project. “We practice conservation before technology,” Mehlman says. “We designed the building to use about 50 percent of the energy needs of a typical building of this size and use. And then we applied clean energy generation systems.”
The solar orientation of the site suited the building’s 136 Sharp 240-watt PV Mono-crystalline Modules from Sharp Electronics Corp., Mahwah, N.J., attached to the CF42R standing seam panels
Also sitting atop the roof are two 1.5-kW/h wind turbines that unfortunately have failed, and the manufacturer has gone out of business. Even without them, Mehlman notes that the building clean energy generation is running far better than they had anticipated.
The average energy bills for the entire building are approximately $300 to $340 a month, Melman adds. “Our goal was to generate about 40 percent of the remaining energy needs, and we have an eGauge System [from eGauge Systems LLC, Boulder, Colo.], which monitors the energy use of everything in the building. With a year’s worth of data, we are generating 61 percent of the energy needs of the building,” he explains.
“The LEED certification is definitely important to us,” Mehlman says. “We have a corporate commitment to green certification of all of our work. Additionally, as we consistently talk the talk, we needed to walk the walk on our own project. I think we have. Our building is actually outperforming our design expectations.”