When the social-services department of a central Brussels municipality bought the contaminated 70,000-square-foot site of a former soap factory in 2005, it established a competition for the design of subsidized apartments. The winning plan by a local firm, MDW Architecture, retains the industrial flavor of the property, which dates back to the 18th century, but transforms it into a sustainable oasis of 42 middle-income rentals grouped around three private courtyards. Named for its precursor, the Savonnerie Heymans is now a model public-housing complex that provides shared green spaces and amenities in a dense but underserved neighborhood on the rebound that is populated by a mix of young people and immigrants, mainly from North and Sub-Saharan Africa and Eastern Europe.

Project architect Gilles Debrun calls the Savonnerie Heymans “a village” that offers protected space for interaction in an otherwise cramped urban setting. Once hidden behind four derelict houses (now demolished), the complex still presents a discreet face to the street—but a welcoming one. All you see from outside is its recessed entrance gate and new community day-care center with tall, playful windows, some in bright colors. An inviting glazed back wall here allows views through to a small garden behind it called the “mini-forest,” which sits on top of the residents' underground parking garage.

Saving what they could, the architects renovated two existing structures that house 10 dwellings. They supplemented these with four new buildings, adding 32 living spaces of various housing types: studios, lofts, duplexes, and maisonettes. The number of bedrooms varies from one to six—a rarity in the old city, especially in subsidized housing. The architects were also intent on providing the inhabitants with collective amenities, such as day care, communal meeting and laundry rooms, and outdoor areas. In addition to the narrow “mini-forest,” there is a playground and the Grande Cour, a large central plaza. The project even has its own concierge.

Reminiscent of Le Corbusier's much larger post'World War II Unité d'Habitation in Marseilles, France, almost all the units open to integrated porches or loggias, protected by operable window walls that fold out and double as acoustic and thermal barriers when closed. These also supply ventilation and some privacy in the close quarters of this “village.”

The architects paid special attention to efficient, low-maintenance measures in order to reduce energy costs during and after construction. For example, they wrapped the new buildings with industrial-style metal panels—a reference to the location's history—backing them with 5'-inch-thick hemp insulation. Then they restored an existing 19th-century steel-frame industrial building, sandwiching a lighter cellulose insulation between a new brick facade and the inner walls, isolating the concrete slabs from the exterior to create a thermal break. This building, which now houses the Savonnerie's lofts, meets the passive very-low-energy building-performance requirements of the Brussels Institute for Management of the Environment (IBGE) and uses less than 7,300 BTUs per square foot a year to heat. Additional sustainable elements include 646 square feet of solar panels for hot-water heating, and rainwater harvesting for toilets and gardens.

To preserve the Savonnerie's sense of place, MDW incorporated various remnants of the factory's industrial heritage. The most prominent, a 131-foot-high brick chimney, rises amid the metal stairways and bridges linking the apartment buildings around it. More than a relic, it is now used to ventilate the underground garage. Similarly, a warehouse from the 1950s was largely demolished to create a playground with a viewing platform. Its surrounding walls were lowered from 33 to 10 feet high, and sections of the old steel beams were preserved as visual artifacts.

Tucked within the heart of Brussels, a city where only 10 to 15 percent of the housing is for low- and middle-income families, the Savonnerie Heymans represents a promising future for a diverse population.

Amsterdam-based Tracy Metz is an international correspondent for RECORD and author of Sweet & Salt (NAi Publishers, 2012).