By Frank Edgerton Martin
L35 offers the following technical information on the fabrication of the ETFE bubbles and their attachment to the underlying structure, both key details for long-term durability:
“Each cushion or ‘bubble’ is made up of three layers of thermically welded ETFE membrane. The thickness of the two exterior layers is 250 μm; the third interior layer is 100 μm. This configuration allows it to support exterior forces safely on its fixed structure. The pneumatic system forms a secondary system, while the wooden load-bearing structure or frame is the primary system.
“To ensure the air-tightness and water-tightness of the seals, the edge of each roof element or ETFE membrane cushion is edged with aluminum bolted to a piece of steel. This piece forms part of the primary structure.”