Where can I buy waterproof stretch material? and what is a Stretch Tent?

https://www.stretchstructures.com/ “Stretch Marquees and Fabric Structures is a multinational company specialising in inflatable structures, stretch tents and stretch fabric creations, with an international reputation for “creative fabric engineering” solutions At the forefront of the market and an industry leader, we are continually developing new fabric membrane products and applying new technologies in a rapidly evolving market. If you would like details on how to purchase our products or information on purchasing our stretch fabrics then please contact us at info@stretchstructures.com or on the numbers below
Stretch Marquees & Fabric Structures
(AUS) Tel: +61 2 8916 6231 (UK) Tel: +44 20 3769 5402 (US) Tel: +1 213 401 2531 (NZ) Tel: +64 9 951 9917