Making a House From the Big Dig’s Scraps

There is nothing particularly new or rare in making dwellings out of industrial waste. Discarded (and stolen) shipping containers section off living spaces in slums from Bombay to Cape Town. Cinder-block and corrugated-metal shanties form the bulk of the favelas perched on Rio de Janeiro’s precarious hillsides.

There is, however, something novel about constructing a house with discarded castoffs that need to be moved by crane. “It’s kind of like Junkyard Wars meets Habitat for Humanity,” says Paul Pedini, sipping a glass of Rioja at the end of another 12-hour workday. He’s sitting in the living room of his recently completed 4,300-square-foot home in Lexington, Massachusetts, which incorporates 600,000 pounds of recycled materials. High above him two concrete Inverset panels—which once formed part of a temporary ramp leading to Boston’s Tobin Bridge—sprawl like Druid hunting trophies, borne by steel beams salvaged from the same site. A 27-inch-wide painted girder that once helped support slurry walls along Storrow Drive now helps brace the home’s 69,000-pound roof. “But it’s incredibly strong,” Pedini adds. “How else could you have a house this size with interior walls on only one floor—or have an Asian garden on the rooftop, like we do?”

Pedini’s Big Dig House is built from highway panels and bridge piers salvaged from the largest public-works project in the history of the United States. First proposed in the early 1980s and breaking ground in 1991, the Big Dig is a 15-year $14.6 billion project that has changed the composition of Boston’s downtown roadways—and replaced its elevated and unsightly Central Artery with an underground roadway. An engineer by training, Pedini worked on the project for 11 years as vice president of Modern Continental Construction, one of the project’s principal contractors. “Paul always took the lead in the most technically challenging issues—ramps with tight-turning radii, superelevated bridges,” says Bill Rogers, construction manager for the Big Dig. “In meetings he’d always be drawing, working with three-dimensional solutions on paper.”

It was at one of these regular construction meetings that Pedini first proposed building a home with discards from the Big Dig. The issue at hand was a surplus of Inverset panels. The prefabricated reinforced-concrete slabs, 10 feet wide and up to 80 feet long, had been used to build temporary ramps and roadways for much of the project. Nearing completion, the project had no more use for them. Nor did project administrators want to pay to store the slabs. Landfill was an option, but burying perfectly good materials didn’t make sense—at least to Pedini. For lack of a better solution, he suggested that he use them to build a house. “At first I thought he was out of his mind,” Rogers recalls. “But the more I thought about it, the more it made sense. We build hotels out of precast elements, and these panels are better than the precast materials used in most hotels.”

It was through a combination of method and meandering that Pedini found his Big Dig House designer in 2003. The then 47-year-old engineer was out looking for a house plot during a morning run through Cambridge, dutifully traversing each of a dozen streets in the rectilinear grid of Cambridgeport. Halfway through his survey he noticed a three-unit Modernist town house, incongruous with the neighborhood’s Capes, Colonials, and Greek revival homes. By chance the designer’s logo was still on display: “Single Speed Design (SsD).” By even greater chance the four-person firm was housed next door in a single-story industrial building. Pedini sent a long e-mail to SsD’s principals, John Hong and Jinhee Park. The pair was intrigued by his proposal, in particular the idea of creating a residence out of Inverset and steel.

“People are literally afraid of using so-called industrial materials in a residence,” Park says. A basswood model of an early prototype building that used Big Dig materials stands on a rusted section of girder beside her desk. Outside, through the rear window of the firm’s main room, one can see the minimalist three-unit town house that first caught Pedini’s eye, where she and Hong reside. A native of Seoul, South Korea, Park studied industrial design there before attending Harvard’s Graduate School of Design in 1997. “In Korea they are less averse to incorporating metal and concrete. For me the difference between an industrial building and a home isn’t in the materials—it’s in the way you use space.”

Pedini invited SsD and one other firm to submit designs for a prototype Big Dig House. “The other firm used very few panels, and only as ceremony,” says Hong, who was raised in McLean, Virginia, and is also a Harvard design graduate. “We tried to incorporate as many recycled materials as possible; we used thirteen Inversets, rebar, and even wooden marine piers that had been submerged for more than a century and were still preserved.”

Selecting SsD, Pedini invited the pair to begin work on a multiuse building he hoped to develop on a plot of land owned by Modern Continental in North Cambridge. The proposed structure was to include 20 condominiums and a café, and would be built primarily from Big Dig materials. Plans included cantilevered Inverset balconies in each apartment and curved Inverset floors that would reproduce the curved road section the custom-cast panels had once formed at Boston’s Leverett Circle interchange. “At first I tried to resist re-creating the form of the freeway,” Hong recalls. “I thought it might be too labor intensive. But then I realized that highway workers are accustomed to working quickly with these materials, and that they could frame a 30,000-square-foot apartment in fourteen days. So I stopped resisting and gave the curve of the highway to the curve atop the apartment.”

The Cambridge project, and SsD’s subsequent Big Dig House design, won the firm Metropolis’s first Next Generation Design Prize in 2004. Unfortunately their work was far less appreciated by Cambridge civic and municipal groups, who were particularly wary of using exposed highway beams and concrete slabs in a building along Massachusetts Avenue, Cambridge’s main thoroughfare. Within weeks Pedini understood that his proposal and SsD’s design would never be approved, so he shifted his focus to finding a site for his Big Dig House. But Park finished the apartment-building drawings anyway, spending the better part of six months and nearly $50,000 on the project. “The research alone was worth it,” she says. “It was like learning to play with a new type of module. Besides, it was a great idea, and I was ashamed to quit.”

Pedini’s Big Dig House sits atop a slight rise in a secluded subdivision known as Six Moon Hill. Founded in Lexington in 1948 by the Architects Collaborative, it features 29 Modernist homes strewn sparsely across its 20 undulating wooded acres. The houses are rectilinear, rationally spaced, and very private; in summer, with the birch and chestnuts in full leaf, residents cannot even see their neighbors’ homes from their own. While the Big Dig House may conform with the subdivision’s spartan Bauhaus spirit—and perhaps even with its stark geometries—its exposed steel beams, broad surfaces of concrete, and sheer mass make Pedini’s home a neighborhood anomaly.

“We had to make several changes in the original design to gain the association’s consent,” Pedini remarks, seated next to his Barcelona-born wife, Cristina Perez-Pedini, in the broad living room. While decidedly monumental, the interior space is surprisingly intimate and warm—achieved through generous overhead lighting and radiant heating dispersed by coils in the concrete-panel floors. The oversize interior—a vast rectangular space parceled by broad floors and exposed stairwells—is redolent less of Bauhaus than of Park’s native Korea, where space is often transitional and single rooms have multiple uses: sleeping, entertaining, and eating. “The first plans were way more Gehry than Gropius,” Pedini says. “But I was told there was no way the neighbors were going to let that first design be realized.”

In early 2004 the four-person Six Moon Hill board approved the modified project with a single dissenting vote. A few weeks later work began, with the specialized labor and equipment necessary to transport, hoist, and position the unusually heavy materials. “You need a minimum 168-ton crane to move a single slab of Inverset,” says Pedini, whose expertise with these modular components was invaluable during all phases of construction. (At one point Hong asked whether a panel could be cantilevered 17 feet. Pedini replied, reciting from rote, that the maximum was 14.5 feet.) “And it cost us $10,000 just to move the panels from the storage site to Lexington. In the end, even for its size, this was not an inexpensive house.”

For SsD, which received an AIA Young Architects Award in January, the design of the house was less interesting than the opportunity to participate in its creation. “The house was born compromised,” Hong concedes. “What we were left with was essentially a single bay from the apartment building we had designed for Cambridge. And we went through the same process. We tried to avoid building a monument, tried to minimize the mass and texture of the materials. But soon after we realized that these were the aesthetics of the materials—and that instead of muting them, our design should try to celebrate them. We’re thrilled to have been involved in this. But if we’re hired to do the next Big Dig House, we’d like to do something a bit more radical.”

Apart from the intimacy created between kitchen and living room, Hong and Park’s design is austere, and almost intimidating. The towerlike interior has exposed stairways and stainless-steel cable railings that look like temporary appendages clinging to the vertical walls. The master bedroom, heated in part by tubing next to a steel ceiling beam, seems almost a solution of convenience, a small cave wrested—and with some effort—from the imposing mass of cement and steel. The lines and volumes are clean, but there is little of the surprising warmth the architects effected on the lower floors. Several exterior views also appear rigid, although these will be softened by a pergola over the front entrance and roof gardens over the garage and roof.

While there is still work to be completed on the Big Dig House, Pedini’s bold idea hardly ends with his massive home. “I’d like to develop the concept of second use on large construction projects,” he says, ever the forward-thinking engineer and contractor. He believes there is a business in building with construction waste—and a balance. “Have it built into the work from the start; make it mandatory when there is federal funding,” he proposes. “If we are going to be building temporary ramps and bridges, we need to look around to see what else might be built in the near future. Does the city need a parking garage, a municipal building? We can then shape the materials used in the temporary bridge for their second use, bolt them together so they can be easily dismantled and reassembled. I love this house and am very proud of it. But I also hope that it will make people take a good long look at the things they are throwing away.”

In 2004, Single Speed Design were the winners of Metropolis’s first Next Generation Design Competition. A description of the early stages of this ambitious residential project, can be found here.