Until recently, the world of builders and architects looked with some reluctance at polymer materials. Considered inferior building materials, they seemed useful only for various finishes of modern kitchens but not so practical that they could be used in large-scale building applications.
However, with new technological innovations that have constantly pushed the capabilities of materials to new limits, polymers are now taken seriously as a legitimate part of the building materials palette preferred by architects.
Considered the better-looking brother of Teflon (PTFE), this relatively new material known as ETFE (ethylene tetrafluoroethylene) is a fluorine-based resin. It seems to have lately become the favorite of architects around the world.
ETFE was brought to the forefront of the public in 2008, on the occasion of the Beijing Olympics, thanks to its use at the façade of the complex dedicated to swimming in the Chinese metropolis, PTW Architects' Water Cube.
Since then, architects have realized the many possibilities of ETFE foil, its ability to express a new aesthetic and replace much more expensive transparent and translucent materials.
The newest and most spectacular public appearance of this material was displayed at the construction of the telescopic facade over 36 meters of the Cultural Center The Shed, recently inaugurated in New York City, The architectural studio Diller Scofidio + Renfro in collaboration with Rockwell Group, designed building.
Brief History of ETFE material
Not long after the many benefits of Teflon were recognized, scientists began looking for similar chemicals that could offer even more appealing features.
The ETFE material was initially developed in the 70s by DuPont as a lightweight, heat-resistant film that served as a coating for the aerospace industry. Since then, the film has been used sporadically in various agricultural and technical projects, such as covering greenhouses and other sunscreens.
Since the ETFE material is quite powerful, it can be extruded into thin sheets, suitable for architectural applications. This not only simplifies the construction process but, most notably for architects, allows ETFE to retain the visual characteristics of its transparency, just like similar materials.
The arrival of this material in architecture happened in the early xxi century, with the appearance of the first complex project of computer-aided design, in architecture. Sophisticated computer programs could finally make forms that were never plausible due to geometry previously considered impossible.
Durable, light, elegant
However, architects have a solid, durable, and flexible material that can be a barrier against extreme weather phenomena, successfully playing the role of windows or roofs. And all of this has only 1% of the weight of ordinary glass. With ETFE, architects can now seamlessly develop projects with vast areas of transparent panels.
In 2001, this material saw its first widespread application as an encapsulation membrane of Eden project spaces in Cornwall, UK, a natural evolution of Buckminster Fuller's Biosphere concept. The consulting firm that worked on this project, Arup, selected ETFE because of its ability to regulate the environmental conditions in the building reliably.
Through its UV transparency – the film from ETFE can be printed with specific patterns and layered to control the solar conditions – an essential element for a structure whose function is to host the distinctive flora of a particular climate. In addition, the architects noticed the low coefficient of friction of the ETFE material. This characteristic prevents dust or dirt from attaching to its surface, maximizing the maintenance requirements of the characters made of this material.
Non-Toxic & Easy to Recycle
Unlike other potentially hazardous plastics for health, such as PVC, ETFE is non-toxic, easy to recycle, and highly stable, enduring extreme climatic conditions. It is cost-effective in production and has a manufacturing process that requires low energy consumption and easy transport, thanks to its low weight. In addition, due to its elasticity, ETFE behaves very well during natural disasters such as earthquakes and extinguishes itself in case of fire.
Perfect for the roof of stadiums
Noticing the success of the material as a membrane of large areas, Arup proposed ETFE in its subsequent projects, such as the Allianz Stadium made in collaboration with the architectural firm Herzog & de Meuron (2005) or the National Water Cube Swimming Center in Beijing, mentioned above. In this second great project, ETFE selection was made for its aesthetics and functionality as a coating, especially for its acoustic qualities.
In the projects mentioned above, ETFE layers are permanently filled with air from a pneumatic system to create air cushion spaces, which ensures excellent thermal insulation and structural stability against strong winds and large loads of snow.
The individual air cushions can be lit with variously colored LEDs that can change the appearance of the roofs to create captivating designs, allowing the building to reflect the pleasant atmosphere of the event inside.
Also suitable for the buildings of the future.
At the same time, ETFE is also experiencing an increase in its use in non-sport architecture, for example, in the design of architects Jose Selgas and Lucia Cano (SelgasCano) for the Serpentine Gallery Pavilion in London.
In addition to using ETFE material to make the pillows above, the architects wrapped 19 different film colors around a steel structure to evoke a kaleidoscopic visual effect.
The emphasis is not only the structure itself, it also focuses on the interaction with people as they pass through, and the reflected/transmitted light ‘playing’ with the interior canvas (the white resin floor is highly reflective to create just that – a canvas).
Architen Landrell completed the design, manufacture and installation in an incredibly tight timeframe, 3 months from concept development to completion.The extremely complicated form required precise patterning and connection detailing before it could be manufactured on site at Architen Landrell (Chepstow) and then installed over a period of 3 weeks on site in Hyde Park.
In another example, Kieran Timberlake Architects' design for the U.S. Embassy in London includes ETFE awnings that would help shade the exterior of the building on the east, west, and south sides while allowing natural light to enter the building.
Undoubtedly Polymers seem to have finally become accepted as valuable building materials, and ETFE has already been used with great success in several large-scale architectural projects. Next, the architects will continue discovering new ways to use this excellent material.