Q. May I use for Schach a reed mat that is held together with wire coated in plastic insulation?

A. Shulchan Aruch, (O.H.629, 1 and 7) rules that schach cannot consist and may not be supported by material that does not grow as a plant from the ground or is mekabel tumah (can become ritually impure). Wire coated with plastic besides not growing from the ground is mekabel tumah too, so it cannot be used as a direct supporting part of the scach.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a