ETFE – or ethylene tetrafluoroethylene – is a creative and lightweight alternative to glass with high corrosion resistance and the ability to withstand a wide range of temperatures. According to Strukturflex.com, ETFE is ideal for outdoor and indoor spaces, which is exactly how the SoFi stadium was designed.
The roof is supported by a double cable network system, which is the largest cable network system in the world. The 1,450-ton cable network system with a length of 75,000 feet was completed in October 2019.
“The cables on which the ETFE sits come from Germany. This is also a very unique system that is not used all over the world,” said Sulaiman.
The final position of the cables creates a double convexity, which in turn creates a sloping roof.
The ETFE roof consists of 302 unique picture frames held in place by picture frame clamps. As of January 22nd, more than 120 of these frames had been installed, weighing between 30,000 and 70,000 pounds depending on the type.
According to Dan Schmitt, Senior Project Manager, Roof Construction, 65 percent of the ETFE membrane is a dotted reflective frit pattern and 35 percent is transparent.
While the frit pattern cannot be seen due to the distance between the roof and the seats, the EFTE membrane itself provides enough transparency for fans to see planes flying over the stadium.
When all 302 are in place, 46 of them can be controlled to open / close while the remaining 256 are permanently fixed.
The 46 controllable panels are designed so that half of the panel opens and slides onto the other half of the panel, creating the opening. It’s a useful feature for hot game days.
“It’s mostly about comfort,” Sulaiman said of these fan experience-related skills.
In total, the roof will be around a million square meters.
Don’t admire it for too long though, because you don’t want to miss the action on the field either.