The working-class neighborhood of South Boston is undergoing rapid change. The formerly family-oriented district is transitioning into an area geared toward affluent professionals, and the 144-unit condominium Macallen Building, completed in 2007, has made South Boston a focal point for residential green building. When developer Tim Pappas started the 350,000-squarefoot, (32516-m2), $75-million Macallen Building in 2004, constructing an environmentally responsible structure in Boston presented many more challenges than it does today. The team had to conduct a great deal of research because there was no regional precedent for what they were trying to accomplish.
Manufacturers did not yet have green-product information, such as recycled content, readily available, and construction workers were unfamiliar with many of the materials and processes needed to make the building sustainable. Nonetheless, the condominium project became the first multifamily residential project in New England to receive a LEED Gold rating from the Washington, D.C.-based U.S. Green Building Council. “Things here have changed amazingly fast,” says Ed Bourget, project manager at Burt Hill, Boston. “The owner was very progressive for the time, and he really pushed the team to exceed the LEED criteria.” Burt Hill and Office dA, Boston, worked together on the Macallen Building’s architectural design.
One of the most notable aspects of the building is its unique sloping green roof. Zoning regulations required the building conform to a certain height at the entry face but allowed a greater height at the back. Rather than opt for a smaller building and tower, the designers steeply angled the roofline. The building is 6-stories high in the front and rises to 11 stories in the back to accommodate additional units while offering residents natural light and views. The architects carved 12 private terraces into the roofline.
Clerestory windows in the terraces’ sidewalls introduce additional natural light into the condominiums. The narrow building form takes advantage of sunlight; according to Bourget, the units’ layouts and window placement bring in enough daylight to make electric lights unnecessary even on overcast days. The roof plane descends almost 60 feet (18 m) over a 200-foot (61-m) run, essentially functioning as another wall. As one of two green roofs on the project (the other covers the parking structure), the plantings are visible to the surrounding area.
The 17-degree slope and terraces suspended above one another make the structure’s lateral support system discontinuous. The structural engineers at Waltham, Mass.-based Simpson Gumpertz & Heger met the challenge with a design that treated the roof as a horizontal beam to connect the staggered truss system. They also had to accommodate the additional weight of the green-roof soil and plantings, as well as prevent water from rapidly cascading off the roof in a heavy rain. “Devising solutions for drainage and the greenroof plantings was an iterative process among the entire consultant team,” explains Matt Johnson, senior project manager at Simpson Gumpertz & Heger. “We started by using reinforced concrete masonry walls to divide the roof into six equal 36-foot [11-m] horizontal modular sections.”
A series of drains along the walls directs water into an overall drainage system that leads to a cistern in the basement. The captured rainfall is used to irrigate the plants on the green-roof area above the parking structure, and overflow water slowly is discharged into the city storm-water system. Anchoring the green-roof plantings on the slope long enough for them to become established also required creative thinking. Slope-stabilization technology used on roadways provided the basis for a solution as the engineers strung polyethylene expandable soil mats with 13,000 individual cells that confined the plant starts in soil along each of the sloping sections. “We basically took existing technology from another application and adapted it for the green roof,” says Michael Louis, principal in Simpson Gumpertz & Heger’s Building Technology Division. “In projects where you’re doing something completely new, it’s a good idea to apply common sense as much as you can.”
The green roof not only slows and captures runoff, but the plantings also help building temperatures remain even. One of the drawbacks of city living is the noise, and the roof soil provides acoustic dampening. A high-performance building envelope with all-cotton insulation thermally enhances the units, increases energy efficiency and helps keep the units quiet. The building’s cooling tower and heat exchangers are located in the concrete garage to minimize noise, vibration and visual clutter. Each unit has a heat pump, and the building’s overall heating comes from Boston-based Trigen Energy Corp.’s steam lines beneath the street, a service that is available in many parts of Boston. Sharing a central plant is a more efficient practice than having many individual heating units. Residual water from the cooling tower’s chiller is directed into the cistern for irrigation use.
The Macallen Building units contain low-VOC products; Reston, Va.-based Forest Stewardship Council-certified wood; and wheatboard core cabinets. Heat recovery helps reduce energy costs, and dual-flush toilets save 600,000 gallons (2.3 million L) of water annually. Residents are encouraged to use alternative transportation; the units are located near public transit, do not exceed the zone-required parking, and offer spaces for shared vehicles and a large bicycle-storage room. The green roof over the parking garage provides a miniature oasis where Macallen residents can gather at the outdoor plaza and swim in a lap pool.
The Macallen Building also contains a fitness facility and gives residents easy access to local amenities. “The condominiums appeal to a wide range of personalities with 30 individual layouts, but residents get to collectively share the environmental benefits and a modern urban living experience,” Bourget says. KJ FIELDS writes about architecture and sustainability from Portland, Ore.
Although the primarily Irish-Catholic population of South Boston has changed throughout the years, many district inhabitants still retain conservative attitudes. A documentary titled “The Greening of Southie” chronicles the development of the innovative Macallen Building in this traditional neighborhood through the eyes of its construction workers. The filmmakers at Wicked Delicate, Milton, Mass., took this unusual track to offer a more personal viewpoint of green building. At the outset, the workers are skeptical and resist the project’s environmentally responsible measures, which deviate from business-as-usual procedures. But as the building takes shape, so does their understanding of sustainability. By the end of the project, many have become environmental advocates, and one even reclaims recycled building tiles to use in his own kitchen. The film tallies up the building’s LEED points along the way. When something goes wrong with relatively untested materials, the documentary offers a critique about the impact of what it takes to meet LEED points. “The film shows a gritty, real-people perspective,” says Producer Curt Ellis. “It’s really an appealing process to watch and a wonderful window onto the world.” The film can be obtained through www.greeningof southie.com and iTunes.
Architects / Burt Hill, Boston, www.burthill.com, and Office dA, Boston, www.officeda.com
Mechanical, electrical and plumbing engineers / Burt Hill and C3, Boston, www.c3boston.com
Structural engineer / Simpson Gumpertz & Heger, Waltham, Mass., www.sgh.com
Landscape / Landworks Studio, Boston, www.landworks-studio.com
Lighting Designer / Ripman Lighting Consultants, Belmont, Mass., www.ripmanlighting.com
Commissioning agent / Demand Management Institute, Wellesley, Mass., www.dmiinc.com
Contractor / Bovis Lend Lease, New York, www.bovislendlease.com
Materials and Sources
CURTAINWALL / Vistawall Group, Terrell, Texas, www.vistawall.com
GLAZING / Viracon, Owatonna, Minn., www.viracon.com
GREEN ROOF / American Hydrotech Inc., Chicago, www.hydrotechusa.com
AIR HANDLER AND ENERGY-RECOVERY UNIT / Trane, La Crosse, Wis., www.trane.com
COOLING TOWER / Evapco, Taneytown, Md., www.evapco.com
GEARLESS ELEVATORS / Otis Elevator Co., Farmington, Conn., www.otisworldwide.com
CORK WALL COVERINGS / Innovations, New York, www.innovationsusa.com
GRASS-CLOTH WALL COVERINGS / Donghia, Mount Vernon, N.Y., www.donghia.com
PAINT / PPG Industries, Pittsburgh, www.ppg.com
CABINETS / Microstrand from Environ Biocomposites, Mankato, Minn., www.environbiocomposites.com
VENEER / Brookside Veneers, Cranbury, N.J., www.veneers.com
LINOLEUM FLOORING / Tarkett Expressions, Houston, www.tarkett-commercial.com/us
CARPET / Shaw Contract Group, Dalton, Ga., www.shawcontractgroup.com
DUAL-FLUSH TOILETS / Caroma USA, Hillsboro, Ore., www.caromausa.com