Six Prefab Concrete Cabins Pop Up in the Foothills of Portugal

SUMMARY uses its affordable Gomos System to construct a 10,743-square-foot prefab development in just eight months.

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Shortly after Portuguese architect Samuel Gonçalves unveiled the Gomos System—a framework for building modular, concrete structures—at the Venice Architecture Biennale in 2016, he was asked to put his prefab system to the test in the foothills of Portugal’s Serra da Estrela mountains.

"The requirements for this project were boldly defined from the beginning," says Gonçalves, founder of the Porto-based architecture firm SUMMARY. "The construction should be fast, cost-effective and changeable over time—which prompted the studio to use prefabricated elements, and to leave parts of the project undefined, assuming immediacy, flexibility, and resources optimization as core themes."

Dubbed VDC after its location in the Portuguese municipality of Vale de Cambra, the concrete building faces northeastern valley views.

The brief called for a mixed-use development with commercial and residential programs. Since the client was primarily focused on the project’s budget, adaptability, and a fast construction timeline, the building’s design was largely left in the hands of the architects, who were free to experiment with a sculptural form.

All components were prefabricated in a factory and quickly assembled on-site. The system "performs at once as structure, insulation, and cladding elements," says Gonçalves. The assembly process took eight months in total.

"The shed roof has a very functionalist intention. As a prefab and modular system, Gomos is supposed to be produced in a place and shipped and installed in many different locations," says Gonçalves. "So we wanted to ensure that it would work well even if it’s assembled in a place with severe rainfall or snow."

"The site is in a neighborhood composed of completely different architecture styles: a kitsch individual house, an anonymous collective housing building, some commercial and industrial facilities—you can find them all within a radius of 500 meters," says Gonçalves. "In this sense, there are no traditional architectural references to follow or respect, and we had very few limitations in terms of form, volumetry, or materiality."

The concrete modules were prefabricated off-site and fitted with insulation, electrical sockets and switches, technical rails, and all mechanical connectors before they were transported to the site for final assembly.

As a result, Gonçalves let the Gomos System define the building’s design direction. To keep costs at a minimum, the precast concrete materials were left deliberately exposed without any additional cladding. As a result, all parts of the construction system are visible.

The living spaces are set back to create space for an outdoor balcony and a roof overhang that protects the interior from unwanted solar gain.

Taking advantage of the terrain’s slope, the architects split the mixed-use program into two floors. The public-facing commercial zone is located on the ground floor, and the residential units are placed above.

With over 7,500 square feet of space, the flexible ground floor can be used as one large space or subdivided into differently sized rooms.

Half of the ground floor is currently leased by a bakery, while the other half is left open as an events space.

While the ground floor was built with simple, prefabricated slabs and structural panels, the first-floor units are all products of the Gomos System. Each individual 485-square-foot "cabin" comprises three-and-a-half modules joined together.

"Designed and licensed as a collective housing building, the project offers individual entrances and complete acoustic separation between the different units," says the firm.

In contrast to the building’s gray concrete exterior, the residence interiors feature bright pops of color from pastel blues to vibrant yellows.

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Accessed via full-height sliding doors, this bedroom is filled with light from the unit’s fully glazed wall.

The small alcove above the bathroom is Gonçalves’s favorite design feature. "It allows for overnight stays in unusual yet comfortable conditions," he says . "This ‘extra room’ has a window, visible in the upper part of the back facade—kids love it!"

A peek inside a bathroom with tile flooring.

Topped with shed roofs, the six cabins create a sculptural crown for the building. The placement of each unit follows "a certain randomness using different alignments and directions to explore the volumetric surprises that result from this process," says Gonçalves.

Each unit has a private entrance on the west side of the building. Half of the units are long-term rentals, while the other half serve the short-term tourist market.

SUMMARY’s upcoming projects include a retreat with 11 cabins in the woods, a multiresidential apartment complex, and a nursing home—all of which incorporate modular and prefab construction.