ISSUE 1/2009 V O L U M E 2 6 N U M B E R 1 Journal of architectural technology published by Hoffmann Architects, Inc., specialists in the rehabilitation of building exteriors. The Greenest Building Is the One that Doesn’t Need Rebuilding John J. Hoffmann, FAIA With the news media and the properly, that lasts its full twenty-year- profession in a frenzy over “green plus lifespan. building” and “sustainable design,” public perception plays a greater role Embodied Energy in defining environmentally conscious Each time a building is constructed, architecture than does responsible energy is consumed. In addition to building practice. New certification the usage of raw materials, energy is programs, such as the US Green Build- expended at each step in the process: ing Council’s Leadership in Energy • Manufacture/extraction of materials and Environmental Design (LEED) • Transportation to site (both of Green Building Rating System, attempt materials and of labor) to quantify building performance in • Construction terms of environmental impact, yet the • Demolition criteria used for awarding accredita- • Reconstruction tion tend to be skewed in favor of popularly identifiable “green” strate- The energy required to construct a gies, such as verdant roofs or light-re- building can be considered “embodied sponsive louvers. energy,” stored within the structure. When a building or a portion of a While it is important to place value building is demolished, this energy is on recycling waste water or incor- lost. porating natural lighting and ventila- In a recent project, Hoffmann Embodied energy encompasses all of the tion into building spaces, neglecting Architects was asked to evaluate and materials, transportation, and labor required less sound bite-savvy basics, such as rehabilitate the concrete block walls to construct a building. Attention to detail proper waterproofing and appropri- of a prison facility. The structure had conserves this energy by promoting longevity. ate installation, can have catastrophic environmental consequences. No been built a scant five years earlier, matter how energy efficient a green and would have scored a number of roof might seem to be, tearing the points on the LEED rating system: the entire assembly off and dumping it walls contained an energy-efficient in the landfill in a few short years six inches of insulation, well above because the underlying waterproofing the standard. Because a prison’s membrane fails has a more detrimen- requirements differ from those of tal impact on the planet than would a other structures, the design needed traditional roof, designed and installed to be especially sturdy and resistant John J. Hoffmann, FAIA, is president of Hoffmann Architects. A nationally recognized authority on remedial archi- tecture, he has developed award-winning building enclosure solutions that emphasize comprehensive detailing, exacting construction, and long-term sustainability. Hoffmann Architects is a member of the US Green Building Council. JOURNAL to damage, as well as long-lasting with tion. While decidedly unglamorous minimal maintenance requirements, concrete block detailing might not fall since, with prison overcrowding, cell under the common parlance of “green blocks cannot go unused for long building,” the environmental impact of periods while upkeep repairs are neglecting such details can be signifi- performed. cant. What the design overlooked were the The Integrated Envelope details. Poor design and construction methods permitted extensive water Building exterior systems are inter- entry into the wall cavity. Due to the dependent, and cannot be treated constant presence of moisture, mold as isolated entities. In an effort to spores developed and proliferated, implement energy improvements in Inappropriate “band-aid” repairs are creating a health hazard for staff and an existing structure, building owners not only unsightly, they create additional inmates. Ultimately, the decision was sometimes fall into the trap of taking impact on the environment when they fail quick-fix measures to tighten their or, worse, damage surrounding building made to completely rebuild all of the elements, which in turn require repair. exterior walls; the mold, an environ- energy belts. At best, such solutions mental toxin, would then require will probably not lead to significant inside a façade, then the potential expert remediation. Meanwhile, energy savings; at worst, failure to con- environmental benefit of improved additional energy (and taxpayer dol- sider the interrelatedness of building airtightness is negated by the energy lars) would need to be expended on components can actually cause new and material expenditure of reha- specialized construction methods and problems, or exacerbate existing ones. bilitating—or even replacing—the added security for the duration of the Single actions, such as adding insula- moisture-damaged wall. project. tion, replacing windows, or sealing The best bet, then, is an integrated Losing the embodied energy of such cracks, can potentially lead to other approach, beginning with assessments a substantial structure after only a problems if not considered in terms of the building’s condition, design, and few years of service could have been of the building enclosure as a whole. construction. Improvements tailored avoided quite simply with proper Should indiscriminate use of sealant, to the specific needs of the structure attention to details and construc- for instance, lead to trapped water can then be implemented holistically, with expert recommendations and construction oversight to see that the program of upgrades is well suited and carried out correctly. Thoughtful plan- ning helps to insure that the financial and environmental benefit of such measures isn’t lost to remediation of ill-conceived actions in the near future. The Greenest Building Is…the One that Gets the Most Attention? While it is true that incorporating green technologies into a structure can be an opportunity to call atten- tion to a company’s commitment to the environment, press coverage could turn negative should those modifica- tions prove ineffective or, worse, det- rimental. Ultimately, the real environ- Failure to properly detail and build this concrete block wall left it open to water entry, mental value of building improvements which led to toxic mold growth. Exterior wythes must be demolished and rebuilt, wasting materials and energy. can be assessed only by enhanced 2 V O L U M E 2 6 N U M B E R 1 It’s in the Details Three-dimensional cut-away views illustrate proper place- ment of each component, while assuring that the detailer has considered each intersection and termination. Below: Pilaster cap detail. Correct detailing of roof penetrations and building intersections can make the difference between a roof that must be thrown out and replaced in a few years, and one that’s still going strong at twenty. building performance, not by the pub- lic response to the upgrades. Design details don’t draw the kind of attention afforded the grander ges- tures of a living building face or system for reclaiming rainwater. But they are just as critical to minimizing ecological impact. As an example, for a build- ing addition, it is not enough to draw Exploded views, as supplements to numerous sections and de- a wall section only through the most tails of components, help workers understand assembly sequences common part of the structure. How and procedures. Below: Limestone panel and coping resecurement that wall will meet existing construc- to three-wythe brick back-up. tion, turn a corner, or open to pen- etrations are details that tend to be brushed aside, but these overlooked design elements are essential to build- ing a watertight, long-lasting structure. By trusting the most complicated and difficult intersections to a contractor’s imagination, designers shirk responsi- bility. Unfortunately, precise architectural detailing rarely captures the attention of the news media. Motivation to articulate and oversee design details is therefore lower than is the drive to make bold and elegant environmental statements. Still, the embodied energy lost by demolishing and replacing poorly detailed portions of such a “green” structure would take decades Note: Waterproofing under coping stone and between limestone panels is shown on other details. to recover, even for the best-perform- ing building. (continued on page 4) 3 JOURNAL Historic Applications Preservationists have been touting the environmental benefits of rehabilitating and reusing older buildings for decades. The National Trust for Historic Preservation reminds building industry professionals that regardless of how sus- tainably designed and constructed a structure may be, any new building creates a new impact on the environment. They note that rating systems like LEED were developed originally for new construction, and that the words “reha- bilitation” or even “reuse” don’t seem to factor much in sustainable building discussions. Historic structures, remarks the National Trust, were often built to be more energy efficient than are today’s Refurbishing, rather than replacing, older buildings saves energy and structures, in that their thick walls, high ceilings, natural materials. Here, restoring steel windows preserved historic character lighting and ventilation, long-lasting roofs, and siting for while minimizing costs and ecological impact. optimal weather exposure were designed to maximize energy must be consumed in melting, re-forming, and