How should the schach be supported?

One should not rest schach directly on metal or plastic, but rather on wooden beams placed on top of the metal poles10. If one’s mats are woven with plastic wire, they must make sure that the schach is placed perpendicular to the wooden beams; otherwise the stalks are being supported exclusively by the plastic wire.
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10. Shulchan Aruch (O.C. 629:7)