Defying expectation and a long civic tradition of hiring big-name architects for signature projects, the Dallas Museum of Art has selected the Spanish firm Nieto Sobejano Arquitectos as lead designers for an expansion intended to “reimagine” the museum’s Arts District home.

Bravo.

Widely respected in European architecture circles but virtually unknown in the United States, Nieto Sobejano was chosen from a field of six finalists, among them Pritzker Prize laureate David Chipperfield and High Line architects Diller Scofidio + Renfro. The DMA expansion will be the first project in this country for the firm and among its largest to date, with a budget estimated at $150 million to $175 million.

To look at the firm’s proposal is to understand why it was chosen by the museum’s selection committee: It was the most elegant of the six choices and also the most logical, deftly answering the museum’s imperatives to become more transparent, better integrate with its surroundings, bring clarity to its internal spaces and add new gallery space for the large collections of contemporary art it will soon inherit. Above all, it was downright beautiful.

“Their concept design mixes a poetic sensibility with a dynamic and sustainable design strategy that respects Edward Larrabee Barnes’ original intentions, all the while preparing us to become a 21st-century museum,” said the DMA’s board president, Gowri Sharma, and board chair, Jeffrey Ellerman, in a joint statement.

The proposal, released to the public last month, would wrap the museum’s north and south facades in a skin of punctured white metal that would glow from within, making the museum a literal Arts District beacon. The new contemporary gallery would be perched on top of the museum, a crisp white box lit by skylights, floating above a broad new roof terrace.

At ground level, a remade plaza would open the museum to Klyde Warren Park, making what is now a glorified driveway into a welcoming space for people rather than cars. (That said, it could use more shade.) The barren Ross Avenue lawn would be transformed into a stepped amphitheater leading into the museum, finally giving it an inviting connection to downtown.

Within, the architects would create a gracious new front lobby and open up the grim and tedious ramped “street” that runs the length of the museum, flattening it and lighting it from skylights. Of some concern: the use of stairs as a central design element, which presents problems of accessibility.

For all these changes, the proposal retains much of the essential structure of Barnes’ original design, which opened in 1984 and was expanded by Barnes in the 1990s. It was, from the outset, a stolid presence in the city, and the expansion made navigation less than straightforward. “The reimagined DMA will be a reflection of the original building, transforming the relationship between art, landscape, and community into a balance of memory and innovation,” the firm wrote in a design statement. Preserving much of Barnes’ structure is a victory for history and also sustainability, reducing the carbon footprint of the project.

In Nieto Sobejano, the DMA has commissioned a firm of unusual thoughtfulness with a distinguished record of museum design and of working with legacy structures, often centuries older than the DMA. It was established in 1985 by Fuensanta Nieto and Enrique Sobejano, who are married, and has offices in Madrid and Berlin. Although this is their first work in the United States, both partners are graduates of the architecture school at Columbia University in New York.

Nieto will be the only female principal to have built in the Arts District, a positive (albeit small) step in the right direction for the city. The project design team also includes the Dallas-based landscape architects SWA Group and Houston-based PGAL, serving as “local” architect.

Nieto Sobejano’s work is characterized by volumes with clear geometries and inventively textured facade treatments. In numerous projects that entail the transformation of historic architecture, the architects tend to form sharp contrasts between old and new, recontextualizing the past without erasing it. In a 2015 lecture at the Architectural League of New York, the couple described the role of memory in their work. “At some point a forgotten memory, an image, a sound or a sentence we recorded reappears in the process of every project: an indication that guides us toward a certain path.”

The firm’s San Telmo Museum (2011), a transformation of a 16th-century Dominican convent in the Basque city of San Sebastián, exemplifies its working philosophy. Punched aluminum walls are juxtaposed with the historic structure, creating an unfolding complex of spaces. Writing in the Architectural Review, critic Catherine Slessor lauded it as “a finely tuned exercise in abstraction, of subtle layering and shifting.” She also praised the firm for its ability to “decode” historic buildings and determine “how such structures can be re-energized to address contemporary functions.”

The firm’s ability to create dynamic facades might best be demonstrated by the Montblanc Haus (2022), a showroom and museum building adjacent to the pen maker’s manufacturing facility outside of Hamburg. (The company is German, not French or Swiss, as is commonly thought.) Modeled on Montblanc’s signature black presentation case, the building is a 100-meter-long concrete box distinguished by a relief pattern (produced by altering the surface depth of the concrete) that stretches clear across the facade, mimicking both an alpine skyline and the stroke of a pen.

Other significant works include the Madinat al-Zahra Museum in Córdoba, Spain (2009), the Moritzburg Museum in Halle, Germany (2008), and the Cité du Théâtre in Paris (to be completed in 2024). In recent months, the firm has also won competitions for museums in the French city of Vannes and the Spanish city of Pontevedra.

Nieto Sobejano has presented the DMA with a convincing design, which is a good start, but only that. The museum must now determine exactly what its dream house will cost, and how it might pay for it. That budget must address not just the new building, but the long-term costs of keeping it up and keeping it staffed.

It will also have to continuously prove, and not just with words, that this expansion is truly a work for the entire city of Dallas, and not for the glorification of the philanthropists who will have their names printed on its handsome new walls.

So far, so good.