What is ETFE? The New Bubble Buildings

Ethylene Tetrafluoroethylene

ETFE Cladding on Media-TIC Building (2010), 22@Barcelona Project, Barcelona, Spain
ETFE Cladding on Media-TIC Building (2010), 22@Barcelona Project, Barcelona, Spain. Photo by José Miguel Hernández Hernández / Moment / Getty Images (cropped)

ETFE stands for Ethylene Tetrafluoroethylene, a transparent polymer sheeting that is used instead of glass and hard plastic in some modern buildings. Compared to glass, ETFE:

  • Transmits more light, which can be regulated for local climates by applying patterns (dots) during the manufacturing process
  • Insulates better
  • Costs 24% to 70% less to install
  • Is only 1/100 the weight of glass

ETFE is often called a miracle construction material for tensile architecture because of these factors:

  • ETFE is strong enough to bear 400 times its own weight
  • ETFE is thin and lightweight
  • ETFE can be stretched to three times its length without loss of elasticity
  • ETFE can be repaired by welding patches of tape over tears
  • ETFE has a nonstick surface that resists dirt and birds
  • ETFE doesn't burn, but melts and self-extinquishes
  • ETFE is expected to last as long as 50 years

Plastics, the Industrial Revolution Continues:

The famous exchange from the 1960s movie The Graduate comes to mind: "One word. Are you listening? Plastics. There's a great future in plastics."

The du Pont family emigrated to America shortly after the French Revolution, bringing with them 19th century skills in making explosives. Using chemistry to develop synthetic products never stopped within the DuPont company, creators of nylon in 1935 and Tyvek in 1966. When Roy Plunkett worked at DuPont in the 1930s, his team accidentally invented PTFE (polytetrafluoroethylene), which became Teflon.® The company, who considers themselves a "pioneer of polymer science with a legacy of innovation," is said to have created ETFE as an insulation coating for the aerospace industry.

The tensile architecture of German Frei Otto in the 1960s and 1970s was an inspiration for engineers to come up with the best material to use for what builders and architects call "cladding," or the material that we might call exterior siding for our homes. The idea for ETFE as a film cladding came in the 1980s.

  Engineer Stefan Lehnert and architect Ben Morris co-founded Vector Foiltec to create and market Texlon® ETFE, a multi-layered system of ETFE sheets. Their architectural cladding system can be seen in this YouTube video.

Disadvantages of ETFE:

  • ETFE transmits more sound than glass, and can be too noisy for some places. For a roof subject to raindrops, the workaround is to add another layer of film, thus decreasing the deafening drumbeats of rain but increasing the construction price.
  • ETFE is usually applied in several layers that must be inflated and require steady air pressure
  • Working with ETFE is too complex for small residential projects

Examples of ETFE Structures:

About the Media-TIC Building (2010):

El Poblenou is an old industrial section of Barcelona, Spain, that is undergoing a great transformation. Since 2000, the urban renewal project, called 22@Barcelona, has encouraged new technologies and innovation to bring 500 acres of prime real estate into the 21st century.

The Media-TIC building shown on this page is part of the overall vision. Spanish architect Enric Ruiz-Geli and his team at Cloud 9 designed the building to be as close as possible to net zero—to generate as much energy as it uses.

Like most all ETFE architecture, the structure is a metal frame covered with plastic and solar panels. Like its CAD design, construction was enabled with digital instructions. The steel-framed cube, 121 feet high (36.94 meters), is different from many ETFE sports arenas in that each facade of the Media-TIC building is clad differently—typical glazing (glass) on two exposures, and an arrangement of inflatable ETFE cushions or pillows on the southeast and southwest sides. Following the sun's impact on the structure, the architect designed both two- and three-layer cushions to "manipulate transparency," thus controlling the amount of sun (heat) that enters the building.

Configurations included:

  • exterior layer print of silver dots and interior layer of green tinted ETFE
  • exterior layer transparent and interior layer green tinted ETFE
  • exterior layer transparent and interior layers printed with silver dots, arranged in such a way that when inflated, the dots come together to create opaqueness

Light meter sensors in each cushion detect heat and humidity and regulate the three-layered ETFE by pumping in nitrogen "fog."  This "pneumatic sun shading" system on the 3-layer cushions is augmented by the 2-layer cushions, which regulate heat with combinations of color tint and print patterns.

There are eight floors above the ground level and mezzanine. The roof contains solar panels, greenery, and rainwater collection facilities.

EMPORIS calls the Media-TIC Building in Barcelona deconstructivism in style. With its technology fully visible, Ruiz-Geli's design looks like the high-tech style of the Centre Georges Pompidou in Paris. It's also highly dependent on computer calculations. Perhaps ETFE architecture is a new style—high-tech CAD deconstructivist.

Learn More:

Sources: Innovations Start Here and Plastics, Polymers, and Resins, dupont.com; What is ETFE film?, Birdair.com; Barcelona City Council press releast (PDF); Projects Media-ICT building, architect's website at www.ruiz-geli.com/projects/built/media-tic; MediaTIC, EMPORIS [accessed September 11, 2016]