Knowing your boundaries
The fabric membrane obviously needs to be attached to the supporting structure somehow. There are two principal approaches: A continuous fixed edge or a scalloped edge with attachment points just at the corners.
With the former, the fabric slides into an aluminium extrusion (just like a yacht mast), which is easily bolted to the steel frame.
The scalloped edge incorporates a fabric pocket or “cuff” through which a cable is run. The cables terminate on a membrane plate which is connected to the primary frame often with an adjustable link. An optional extra with this design is a rainwater diverter upstand that allows you to collect rainwater.
