How to add new support webbing to a patio chair?

We have three lightweight aluminum chairs (not the folding lawn chair variety) that are in good shape, except for the seat support webbing. The webbing is made of some sort of elastic material, and I cannot tell how it may be attached to the frame of the chair.

Sitting in the chairs becomes uncomfortable after a while, as the webbing will sag under an adult's weight. Older folks in particular find it difficult to get up out of the chairs.

I would like to either replace or supplement the existing webbing with something similar, to improve the support of the seat cushions.

1) What material might be suitable for this project?

2) What options for attaching and tightening the webbing to the chair frame are recommended?

3) Does anyone know of instructional videos (on YouTube or elsewhere) that would provide some insight into a solution?

See attached images.

Thanks...

JGB

 

Those chairs are probably intended to be used with a pad or cushion that spreads out the weight and would sag less. The webs are probably fastened with a clip that is inside the wrapped part. The webbing stretches slightly when the clip is installed and then tension keeps it in place. Unlikely to be removed without cutting the web.

Two inch wide vinyl webbing in continuous strips is available for weaving a seat, however since your chairs do not have a large bar across the back that may not work. The tension from a weave on the thin bar is likely to bend it.