Gerding Collaborative Pushes Virtual Modeling to LEED Platinum Success

By Steve Hodgdon
Special to AECnews

When Dan Gerding started the Gerding Collaborative architectural firm in his spare room in 1993, his interest was in incorporating natural systems and resource conservation into his building designs. His most recent project so successfully marries virtual modeling with green design that it has become one of about two dozen projects worldwide to earn LEED Platinum certification.

The Sweetwater Creek State Park Visitor Center near Atlanta, Georgia is also the first building project in the southeast US to earn LEED Platinum certification, the highest level of eco-friendly building achievement from the U.S. Green Building Council. The Center requires 77% less water and consumes 51% less energy than comparable buildings, to name just a couple of its virtues.

It’s also a prime example of how building performance can be optimized through the use of an integrated design team of architects, engineers, environmentalists, interior designers, contractors, building staff and other stakeholders to blend the building naturally into its surroundings and capture maximum benefits from the environment. Virtual building technology enabled the collaboration, allowing the team to interact with 3D design models as well as the Building Information Modeling (BIM) data used for predicting building systems’ performance.

Gerding Collaborative currently has nine full-time employees, which are a mixture of technical staff, architects and interior designers. The firm has a diverse portfolio of public and private projects, but primarily focusing on institutional work like Sweetwater Creek. “I got on board with the concept of virtual modeling early on,” said Gerding. “It just seemed like the right direction—the way we used to do things, using two-dimensional drawings, was sort of archaic. We like to be at the forefront of technology, which is why we employed virtual building software.”

Getting Everyone on Board
Once Gerding and the Georgia Department of Natural Resources (DNR) agreed on a vision of a sustainable design, Gerding realized many other decision makers would need to be persuaded.

“We were working with a large design team that consisted of mechanical engineers, electrical engineers, plumbing engineers, the landscape architect, structural engineers, and the civil engineer,” he said. But in addition to the design team, Gerding needed a way to showcase the ideas and gain consensus not only from the DNR staff, but from a group of project fundraisers who held a significant portion of the purse strings. “This was a rather unusual building, both in concept and appearance. We needed to make sure that everyone had the same idea about the final structure,” he said.

Gerding’s architects and engineers were already skilled in ArchiCAD virtual building software, which gave them the 3D visual aids to display, communicate and enhance the project to the others. Gerding presented the group with a building design fully integrated into the landscape, blending in with the surrounding hillside and leaving a very minimal footprint on the environment.

While the initial design had more modest green building aspirations, the design team realized that this project had the potential to garner a higher level of LEED certification than any other project they had worked on. “The project kick-off meeting was really a LEED kick-off meeting. We had all of the stakeholders and design team members in one room, and we identified the credits we thought we could achieve with this project,” said Gerding. “Given the budget and other parameters, we initially came up with a project at the Silver level.”

As the design ideas started flowing, Gerding’s team captured them fluidly in the virtual building environment. To approve the final design concept, the team was able to show 3D views of the building from all angles, displaying how the roof was going to be a natural extension of the hillside. According to Gerding, “Being able to model the building in that way, with that level of detail, got the stakeholders and our client really excited about the project. That excitement kept the design team’s momentum moving forward because we were all able to agree that this was a special opportunity.”

The technology not only provided a visual model of structure, but also demonstrated the sustainable design features to minimize the building’s effect on its surroundings and maximize the on-site environmental benefits, like tree shading and solar radiation. “We were able to conduct sun studies of the south face of the building to fine tune the size and location of the shade devices and light shelves,” said Gerding.

This ability to experimentally optimize the building position allows the sun to provide heat to the building’s interior in the winter while almost completely eliminating the sun’s direct rays in the summer. The high performance building also features composting toilets, vegetated roof, rainwater capture, bio-retention ponds and photovoltaic solar panels. The composting toilets and rainwater capture system eliminated the need for leach field, saving both trees and money. The graywater system provides water for the low maintenance gardens, eliminating the need for an irrigation system. The vegetated roof helps insulate the building while serving as an outdoor gathering plaza, further reducing the building’s environmental footprint. Taken together, these eco-friendly features helped reduce water waste by more than three-quarters, and energy consumption by more than half of comparable buildings, avoiding 27 tons of carbon emissions annually.

The technology allowed the architect to share 3D views of the interior with the design team and the client, giving them the ability to explain the concepts clearly. Decision making was easier, better informed, and consensus-driven. The design team was able to continuously collaborate during the conceptual phase using a succession of 3D virtual models to create “what-if” scenarios. For example, mechanical engineers could easily understand how the building’s orientation minimized the amount of sunshine coming in and heating up the interior, downsizing the mechanical systems as a result. This downsizing provided big savings in electricity and equipment costs, resulting in cascading benefits that they might otherwise have missed.

Going for Platinum
As the design progressed, the team realized that they were within reach of being able to exceed their own goal of LEED Silver certification and decided to push for more credits. “Being in a conservation park made the project a perfect opportunity to make a strong statement about resource conservation and respecting the natural environment,” Gerding said. “The mission of the park is to be a cultural and a natural resource. We feel we created a building that is really second in line to the environment—it sets a conservation example for the state of Georgia.”

The U.S. Green Building Council awarded the Visitor Center Platinum level LEED certification. In the LEED-NC (new construction) category, Sweetwater Creek is only the 20th building in the world to be awarded the Council’s highest distinction.

“Our firm has keen interest in sustainable design, and achieving LEED Platinum certification helped make us leaders in this movement,” said Gerding. “Virtual building technology gave us the platform to visualize the projects better and be more confident that when we put the designs in front of our clients. At each step of the process, we were generating various views of the model to discuss ways to better integrate with the surroundings.”

Steve Hodgdon is a freelance writer based in New Hampshire.