Resting lightly on the land

August 11, 2010

In terms of sustainability, this one is out there. Engineered to protect a fragile ecosystem and to serve as a model of environmental stewardship, the gizmo-laden metal and wood box is meant to serve as built proof of its owner's mission. The shedlike form rests lightly on concrete stilts by the shore of the Chesapeake Bay, powered by the sun, rainwater and prevailing breezes. By all measures, and despite considerable odds, this experiment succeeds.

The headquarters offices for the Chesapeake Bay Foundation (CBF) not only faced normal not-for-profit hurdles; it had to contend with deeply ingrained design and construction practices. Conceived to integrate a mile-long list of green features unfamiliar to most building teams, a committed construction partner was essential. 'We used many products that are not in general use in the building business,' notes A. James Clark, a longstanding supporter of CBF and chairman and CEO of Clark Enterprises Inc., parent of The Clark Construction Group, which served as general contractor. 'However, we all benefit from additional knowledge regarding the new materials.'

With a GC on board early, a complex design-development phase began that was marked by an exacting, perhaps excruciating eye for detail and refreshingly democratic decision-making - an approach that could paralyze a typical commercial venture. 'The team at work here constituted CBF trustees and staff who worked together with determination,' says William C. Baker, president of the environmental group. 'We had all kinds of internal teams for everything from design and color to value engineering and interior programming.'

But for the single-minded focus of this nonprofit environmental group - whose mantra 'Save the Bay,' seems its sole guidepost - such a project could never take form. Support from a highly interdependent building team, however, sharpened its scope and scale to the truly cutting edge.

Enabling technologies

CBF had developed numerous small educational centers around and upon the bay, and encouraged designers from SmithGroup's Washington, D.C., office to employ their favored building concepts. A rainwater catchment system and photovoltaic panels were incorporated, as were vernacular metal panels and wood structure. Some of the largest orders to date were placed for parallel-strand lumber (PSL) and arsenic-free, 'certified wood' for the exposed timber structure. Composting toilets - waterless commodes wide-piped to an aerated decomposition tank - saw what was surely their first-ever use in an office setting. 'We've used these for 20 years and have found them to be very workable,' says Baker. 'So when we wanted to develop an office building project, we said, 'We don't want any flush toilets.''

Paradoxically, says Tom Eichbaum, who as principal at SmithGroup led the design team, 'The technology in the building is not really high-tech. Everything is relatively conventional, and some of it even takes you back, such as the operable windows and cork flooring.'

Even the image of the building, with its shed roof, is inspired by a traditional, indigenous form. 'It recalls the shed structures of the bay,' says Eichbaum. 'The watermen unload their daily catch into what look like big garages on stilts.' The single slope of the shed also meant a single gutter, easing rainwater collection to three elevated cisterns for domestic use, landscaping and fire suppression. More important, the narrow, 50-ft.-wide floor plate offered a European approach to office design, keeping all occupants close to natural light, views and fresh bay air.

'To take full advantage of daylighting and natural ventilation, it had to be open-plan offices,' something new for CBF staff, says T. James Truby, principal of Synthesis Inc., a project-management firm based in Columbia, Md., that served as CBF's representative. 'That required a fair amount of soul-searching.'

When the employees finally signed off on the design concept, the building team still faced its greatest challenge: How to make the project as 'invisible' as possible - in other words, to minimize its environmental impact.

The unbuilding

'We started with the premise that the greenest building is no building at all, and the greenest things are things that aren't there,' says Charles D. Foster, CBF's director of fleets and facilities, who also happens to be a native and a licensed bay waterman. As an example, he cites the building team's decision not to fill nailholes on interior finish wood, which also saved $30,000. 'So we said, 'Let's make sure the building's as small as possible, with nothing that doesn't have a purpose.'

After some discussion, it seems that CBF elected to include every possible green feature - and to avoid every possible intrusion on the environment. Focused solely on cradle-to-grave impact and indifferent to budget and time constraints, problems were inevitable. 'When it was finally designed and we bid the project, it came in over budget,' recalls Barbara C. Wagner, vice president with Clark Construction. 'So we spent time value-engineering, looking at areas that had no impact on sustainability.'

In spite of the cost-cutting and other issues of feasibility, the team worked with a seemingly endless list of sustainable concepts and equipment. Team interaction was critical in ensuring they would work as expected, especially novel materials such as PSL. Other examples:

  • Siting. Located on a rather remote site of a defunct inn and beach club, the plan required minimal landscaping and the felling of only one tree. Yet, 'It was not clear at all that the site would serve CBF's purposes,' says Truby of Synthesis Inc. 'While it was large at 33 acres, it had little developable land and included wetlands and unstable soils.' In addition, accessing and building on the site was a concern for contractors and for CBF, as was future employee travel to and from the offices.

Based on advice from the GC, engineers and environmental experts, CBF found the location suitable. 'It was better than cutting down upland trees, and we knew we could control the impact of the building by controlling rainwater ... and through created wetlands,' Baker explains.

  • Mechanical and electrical systems. What Foster terms 'bleeding-edge technologies' were considered for mechanical, electrical and plumbing systems, including automatic dimming controls for lighting, a total energy-management system and a desiccant dehumidification and cooling system.

'What's really impressive is how they're integrated and tied together design-wise. Everyone from the contractor to the engineer to the landscaper was involved,' says Foster, citing coordination of envelope design and mechanical system sizing as an example. 'So we made more informed design decisions.'

SmithGroup's Mella recalls a similar example. 'To figure out what thickness of structural insulated panels [SIPs] to use, we worked with the mechanical engineer to get the desired R-values for the roof and with the structural engineer to determine the span of the SIP,' he says. In the end, a 12-in.-thick panel with an astronomical R-45 gave way to an 8-in. panel with a still respectable R-34. The thinner SIP was less expensive, but necessitated the addition of timber purlins for support.

  • Waste and toxin management. Follow-through on material selection and job-site practices was critical to the construction phase, says Eichbaum. 'It's one thing to write a specification that all waste materials be recycled, or that all materials be free of VOCs, but the notion can be totally foreign to contractors, and they have to pass that onto all their suppliers,' he notes.

Fortunately, Clark had experience in those areas. 'We're seeing a lot of recycling programs for construction waste. You have to make sure you're not comingling debris and that you use demolished materials where you can,' says Wagner, noting that concrete from the demolished inn was used as roadbed.

  • Structure. Concrete was also a favored material for the foundation, a conventional slab-and-beam deck with spread footings, adds Steven E. Colby, project manager for structural consultant Shemro Engineering, Bethesda, Md.

Offering an effective fire separation between the timber structure and parking areas below, concrete also helped support heavy offset loads. 'Exposure to salt water and air did not favor a steel structure,' adds Colby. 'And some environmental aspects are better with concrete.

'The project required more coordination than a typical job, because the structure is the architecture and the architecture is the structure, and everything is coated naturally,' adds Colby, noting that hot-dipped galvanized steel was specified for most connections on timber joists and beams to help prevent rust.

  • Interior finishes. Inside the structure, the lack of commercial finishes and fixtures is striking, but the austere approach is considered an environmental plus. Offices can be reconfigured without sending materials back to the landfill, says Baker, and there are fewer barriers to staff interaction. 'We also learned that by not having walls and doors, the energy efficiency of the building really improves,' he adds.

Interior trim is mostly SIPs and pressed wood fiberboard, materials that are new to most carpenters and building inspectors. The solid expanded polystyrene insulation in the exterior walls meant that electric chases were not possible, making coordination with the electrical trades all the more important. For flooring, the team settled on a mix of materials: old-fashioned cork and trendy imported bamboo, which is rapidly renewable.

What's not there

Like the rest of the project, the interiors are most remarkable for what's not there. In seeking to make their office shed 'invisible' to the habitat of the bay, this project team earned high honors: The world's first 'platinum rating' from the U.S. Green Building Council's environmental rating system, called LEED.

Why is it the first top-rated green project? 'Because the team understood the mission,' says Donna McIntire, a program manager for the council and formerly a project manager for the CBF headquarters. 'The owner had a huge role in that. It does take a strong client, and we're finding that long-term owners of buildings are leading the way.'

Baker and the CBF seem to attribute their success to the project itself, as if it were another building team member. 'We got led along by the mission of the project, and that's what happens when you're a goal-driven organization,' Baker explains. 'We weren't looking to do something that ambitious, but it grew from being a way to have everybody under one roof to a teaching tool for everything from energy efficiency to environmental sensitivity.'

The project does instruct, mainly by raising questions. For example, will the products and techniques employed become more cost-effective, workable and readily available? Or, like solar power, will it be decades before they can be applied across the commercial construction market? Where, for example, can composting toilets be used, and how do existing codes prevent their use? How much energy is required to make PSL or SIPs, and how clean are the manufacturing processes?

By provoking such thought, the CBF headquarters proves that it is more than mere design and construction: it is study of what is possible and what is true.

 

Construction Costs

M/E/P systems $1,650,000
Timber 1,000,000
Foundation/concrete 500,000
Roofing 150,000
Above-ground tanks 75,000
General conditions/other const. 3,825,000
TOTAL $7,200,000

 

 

         
 

Comments on: "Resting lightly on the land "