ETFE (ethylene tetrafluoroethylene) has emerged over the past two decades as one of the most transformative materials in stadium architecture. It was originally developed by Depont for aerospace applications. Its inherent properties—light transmission, structural efficiency, durability, and minimal weight—have made it particularly suited for long-span architectural applications.
ETFE was first introduced in architectural applications in the mid-1980’s but gained more traction in the late 1990’s and early 2000’s as designers sought alternatives to glass and fabric for large scale structures.
The Eden Project (2001) by Nicholas Grimshaw in the U.K. was an early proof of concept. It used ETFE cushions to create a series of transparent domes that emerge like bubbles amid a verdant landscape. While in 2005, the Allianz Arena in Germany by Herzog and de Meuron established ETFE as a defining material in stadium design. Its inflated ETFE facade panels, capable of changing color, showed how the material could function not only as a building envelope but as a dynamic architectural statement.
Over the next 10 years across Europe and Asia, ETFE became increasingly common for diverse building typologies requiring lightweight structures, natural daylight, visual transparency, thermal performance and visual expression. It began to establish itself as a viable alternative to glass and fabric in most building typologies and a preferred material for stadiums. The Beijing National Aquatic Center (“Water Cube”) used ETFE to create an expressive facade and roof at the 2008 Summer Olympics. In 2011, the Forsyth Barr Stadium in New Zealand ETFE delivered the first fully enclosed stadium with a natural turf pitch.
In contrast, North America was slower to adopt ETFE, partly due to the need for new testing protocols to meet U.S. building codes and the industry’s risk-averse culture, which reinforced a long-standing reliance on conventional materials. With relation to stadium applications, during this period North American stadiums either emphasized open-air venues or integrated retractable roofs where traditional opaque materials were suitable. From 2008 to 2016, I was vice president of facade engineering at Thornton Tomasetti, leading ETFE design efforts on major stadiums including U.S. Bank Stadium, Hard Rock Stadium, and the BMO Stadium.
The U.S. Bank Stadium in Minneapolis became the first NFL stadium to use the material at scale. Completed in 2016, the project features 240,000 square feet of ETFE. Initial concepts called for the integration of an operable roof, the popular approach of the day. However, with the desire to pivot toward a more innovative solution, we pushed the concept of integrating ETFE by selling the concept as the “new retractable.” Here, ETFE provided the best of both worlds: the visual connection to the environment, comparable to the open ode of a retractable system, while providing spectator and player comfort more associated with the closed mode all within a more cost-effective fixed roof structure. This project demonstrated ETFE’s advantages and effectively validated the material for large-scale NFL applications.
During that same period, I worked on the renovation of Hard Rock Stadium in Miami. Here we integrated ETFE at the inner edge of a new lightweight canopy and developed complex “oculus” skylights around massive masks that supported the entire canopy. This was a new approach in the U.S., an open-air stadium that integrated localized protection for spectator comfort, a shift toward passive environmental strategies rather than fully conditioned domes. In addition, the project quietly positioned itself as the most sustainable stadium in the NFL by reusing a significant part of the old stadium, reducing new materials and cutting total embodied energy by nearly 70 percent.
BMO Stadium represents an important step in the evolution of contemporary stadium design in the US, translating lessons from Hard Rock Stadium into a more refined, climate-responsive canopy. The progression continued with SoFi Stadium in Los Angeles, completed in 2020. The stadium took the partial open-air typology to a new scale, by creating a canopy that spans over the entire stadium and the adjacent plaza and entertain district. The canopy, a cable-net with a single layer ETFE application became the stadium’s defining feature. SoFi’s application leveraged ETFE’s lightweight properties and structural capacities making the ambitious scale viable.
Sustainability is a critical consideration. An ETFE roof system delivers a lower life-cycle carbon footprint than traditional enclosures. While carbon-intensive per pound, its ultra-lightweight properties drastically reduce total material use, lowering embodied carbon while also minimizing structural steel demand. When evaluated holistically, ETFE provides a significantly more sustainable solution for large-span stadium enclosures.
Together these projects mark a shift in stadium design in North America and ETFE is poised to play a critical role in the next generation of NFL stadiums.
Today, I lead my own practice focused on the integration of architecture and engineering to deliver innovative, high-performance design solutions. This approach is reflected in our proposal to reimagine Soldier Field for the Chicago Bears, where we applied lessons from several decades of stadium design, urban planning, and development to address both technical and civic challenges.
Rather than replacing the stadium, the project demonstrates how an existing venue can be upgraded into a sustainable and resilient modern venue. ETFE’s ultra-lightweight panels make it uniquely suited for retrofitting existing stadiums where structural capacity is limited. It enables a new enclosure to be constructed above and outside the existing footprint without overloading the structure, avoiding costly demolition and the financial burden of a full rebuild. The design leverages ETFE’s high-performance properties creating a climate-controlled environment. The design utilizes a multi-layer ETFE system with an integrated frit pattern for variable solar control for enhanced thermal performance maximizing spectator comfort for events throughout the year. The central portion of the roof over the field remains transparent without a frit pattern allowing the transmittance of UV light for the health and use of natural turf.
Structurally the new enclosure integrates an efficient long-span structure that extends over the existing stadium minimizing the impact of the new foundations on the existing structure. The roof’s geometry and panelization leverage ETFE’s inherent properties to form an efficient skin that responds to Chicago’s unique and harsh lakefront microclimate. The impact of snow, ice, and wind are controlled without impacting the historic structure of Soldier Field. Beyond the roof canopy, the design engages two distinct contexts, the lakefront park system and the South Loop neighborhood to the west, both interfacing and connected by the newly formed concourse-level plaza, which establishes a new connective tissue and experiential urban space. The result is a year-round world-class venue that is more than a stadium, it’s a new destination in an already dynamic city, capable of hosting a multitude of sporting events, concerts, and expositions.
Edward Peck is an architect and recognized pioneer of ETFE and lightweight structures. For nearly 30 years, he has been involved in the design and engineering of some of the most iconic stadiums and sport venues around the world. He is the design director for Edward PECK DESIGN, an international and multidisciplinary design consultancy operating at the intersection of art and science synchronizing architecture, engineering, and landscape in the development of innovative and contextual solutions for the built environment.