Madrid’s Ombú, a historic office building used by the Spanish infrastructure and energy company ACCIONA, has just reopened with a sustainable new design. This retrofit project makes a beautiful brick and glass building into a space aiming to revive the local area around it. Ombú has over 100,000 square feet of new office space and combines private and public land with sustainable green space that extends to the adjoining Méndez Álvaro station.

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Front of the Ombú office building

Ombú achieves a 1.0 Ecological Footprint as its carbon emissions will be absorbed by the current capacity of Earth. As required by the Paris Agreement, the design balances carbon sources and sinks while matching its environmental impact with the agreement’s original +2 degrees Celsius warming cap target.

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Front of the office building at night

Foster + Partners, who designed the building, say that the redesign of Ombú helps to transform an industrial wasteland into a new garden in the city. They also explain how Madrid’s mild climate allows workspaces to be partly outside, which then creates an enjoyable lifestyle for workers in the Ombú building. Further, they brought natural materials into the existing brick building, creating biophilic spaces that aim to be good for employee wellbeing as well as productivity.

A small canal near the building

Meanwhile, the new courtyard connects to an about 133,000 square foot park with 350 trees that include outdoor workspaces. To reduce water consumption, local species of trees were planted. The water also comes from local sources in the Arganzuela district.

Inside wood structures and high ceiling

A double tier of open wood decks within the open shell of the Ombú building creates floor space for workers while softening the industrial look of the space. The original building was built by architect Luis de Landecho in 1905. But after its first run as an energy plant, it hadn’t been used in a while until ACCIONA acquired it in 2017 to save it from demolition. Steel trusses now hold up the load-bearing outer structure, creating a reinforced and modern shell to house open workspaces. Using the original building shell also conserves over 11,000 tons of original brick.

A wooden balcony near large windows and a photo showing the wooden ceiling

The inner decking is a lightweight sustainably sourced timber from local forests and allows for flexible use of the space while integrating lighting and ventilation. The timber decking is demountable to further allow for flex use of the space in the future, which will also save about another 1,700 tons of CO2.

Wooden pillars support the office

Additionally, central skylights bring natural light inside, which reduces the need for artificial lighting. Glazed windows include photovoltaic solar tech to generate electricity for the building.

The Ombú building project was presented as one of the most sustainable buildings yet by Foster + Partners and as a case study for the World Green Building Council. The concept of Ecological Footprint also helps quantify and improve the impact of a project across all aspects of development. Carbon footprints are measured and controlled, and this design reduces embodied carbon by 25% over the life of the project. Overall, operational energy is 35% below normal expectations for a similar building using conventional construction methods as well as materials.

+ Foster and Partners

Photography by Nigel Young