Jordi Surroca

Outside in, top to bottom, the Torre E.I.0.5 apartment tower in Hospitalet de Llobregat, Spain, looks a bit like an M.C. Escher building of visual infinity. What seems like a five-floor building that blends in with the neighboring 1960s and 1970s residential buildings is really a space-maximizing, fully recyclable 15 floors with 75 apartments.

Barcelona-based Roldán + Berengué (R+B) completed the 111,007-square-foot tower as part of the Plaça Europa, a node on the Grand Via de les Corts Catalanes, the longest road in Spain. This last node in the master plan for Barcelona, Europa, is focused on social housing.

In Spain, buildings for social housing prescribe both minimum and maximum floor dimensions—fixed in this case at 79 feet square—leaving the architects with little room to maneuver and design. R+B overcame this restriction primarily by playing with the typical façade-building relationship. In this project, “the inside is overlapping the outside,” says principal José Miguel Roldán. While the façade itself stays static, portions of the volume recess 20 inches to 7 feet back to form “megawindows.”

In this framework, the architects grouped together five sets of three floors each, and framed each set with the brise soleil. The effect is a trompe l’oiel where the building only seems to have five floors from far away. Sheets of 8-millimeter-thick, high-pressure laminate panels hang off of a hidden structure of recycled aluminum to make the megawindows, which are nearly 33 feet high with varying widths.

This exterior strategy helps the building look smaller than it is, but also gives each apartment shading, ventilation, and three solar and visual orientations, with views of Tibidabo Mountain, Montjuïc hill, or the Llobreagat River. “We called it ‘multifocality’ of the building,” Roldán says.

Once the firm designed the outside, it then went inside, distributing the program from the top. On each floor, a double-loaded corridor divides six units. The units have 9.3-foot-tall ceiling heights that offset their small size, which ranges from about 603 to 2,110 square feet. The top-down design was done so that “the compacted residential volume on the superior floor releases a space three levels tall, with a T-form in the lobby,” says Roldán, who calls the lobby an “interior street.” The mail lobby is at points 22.3 feet and 33 feet tall.

For the building’s construction, the firm evaluated material origin, fabrication energy, CO2 emissions, and capacity for end-of-life recycling. The firm estimates the life cycle to be 50 to 60 years for the façade. Each material had to be made out of recycled material and be recyclable itself. Steel bars in the concrete structure, aluminum in the brise soleil, and wood in the interiors are all 100 percent recycled and recyclable. The finished structure may be tossable, but it’s certainly not toss-worthy. Its well-executed design won’t be easily discarded.