Architects Guide to Glass
A special section of USGlass magazine

First in Fashion
New Glazing Trend Sets the Stage for Future Façade Applications
by Ellen Rogers

Sometimes it’s the simplest of ideas, designs, fashions and trends that make the biggest statements. Think Audrey Hepburn circa Breakfast at Tiffany’s. To this day few items make as much of a fashion statement as a simple black dress and a few strands of pearls. And a simple, yet memorable statement, was exactly what the Spanish architectural firm of Rafael de La-Hoz was going for when it designed the new facade for the home of Inditex, the company behind fashion brands such as Zara, Pull & Bear and Massimo Dutti, located at Castellana 79 in Madrid, Spain.

“We were looking for an abstract and plain composition for the façade that wouldn’t penalize the view from the inside because of the façade ‘character,’” says design architect Francisco Arévalo. “The client’s request was to have a singular building, but discreet at the same time, with an impeccable function as an office.”

Glass and glazing materials played a key role in bringing this architectural creation to life. Arévalo says they looked to the squares of a chessboard as the design inspiration, while also incorporating a double skin to provide natural daylight penetration.

“This resulted in a neutral, abstract and plain façade, but at the same time [one that is] alive, with volume.”

Setting the Stage
When it came to the early stages of the design process, Arévalo says the location of the building within the city posed a challenge.

“Located next to one of the best office towers in the country of one of the great masters of 20th century Spanish architecture—Francisco Saenz de Oíza—[the location] raised the idea of respecting the past, yet being able to differentiate our styles from the rest of the buildings without much architectural show-off,” says Arévalo. “We could not compete with the Banco de Bilbao Tower in height (it stands 107 meters) nor the location, but we [also did not want to] merge with it.”

He continues, “These urban premises and the client’s requests to have a singular, but at the same time discreet, building, conditioned the concept of the project from the very first moment.”

So when designing this new office building, Arévalo says a number of components came into play. These included not only the aesthetic, but also the performance features.

“From our experience, especially with office buildings in Madrid, having a double-skin façade helps the interior comfort, both acoustically and thermally, so we considered this façade solution from the very first moment,” he says. “The building location, in one of the great thoroughfares of the city and the south orientation, also advised this solution.”

But there was also the aesthetic appeal—the checkerboard appearance—and the question arose as to just how to make such a look work, while still ensuring the views of the outside from within.

“We searched all sorts of glass treatments: silkscreen with different degrees of opacity and color, [acid] treatments, sandblasting, [working] with different colored sheets of butyrals, but all of them affected the view from the inside,” says Arévalo.

From our experience, especially with office buildings in Madrid, having a double skin façade helps the interior comfort, both acoustically and thermally, so we considered this façade solution from the very first moment.
—Francisco Arévalo,
Rafael de La-Hoz

Then there was the idea of incorporating a metal. Arévalo explains that on many other projects his firm has worked with companies that specialize in laminated glass with metal meshes, but the concept never worked well. For example, a true metal mesh can come with a high price tag, for one, and also add weight to the glass, making it difficult to work with and install. Other reasons he says such previous materials were unsuccessful include the fact that they had either not passed testing requirements for use on façades or did not meet their architectural aesthetic expectations.

Already working with DuPont’s SentryGlas laminated glass products, the architectural team soon learned of a product called Sefar Vision, which is an alternative to traditional metal mesh; it’s a metal-coated fabric interlayer, typically laminated within glass or other transparent materials.

Peter Katcha, director of North American sales with Sefar, says that while double-skin facades are popular in Europe, creating one with just a laminated glass product does not provide much of an aesthetic, and the aesthetic feature was something architects were looking to capture.

“[DuPont] introduced Sefar Vision in combination with SentryGlas, which provides a nice aesthetic, an almost 3D appearance to the façade,” says Katcha.

While Arévalo says he was interested in working with the Vision product, there was a challenge: at the time it was not approved for use with glass in an exterior façade in Spain.

“We had samples of laminated glass with metallic interlayers and Sefar meshes in the office, but none of them could be used at that time outdoors,” he says. “We got in touch with official Sefar suppliers in Spain and after several negotiations we reached the [opportunity] to use it, since it was already in testing and standardization processes in our country and [and would be ready in time to meet] construction dates.”

Ellen Rogers is the editor of the Architects’ Guide to Glass & Metal magazine. She can be reached at erogers@glass.com or follow her on Twitter @AGGmagazine and like AGG magazine on Facebook to receive updates.

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