The plastic material is polycarbonate, one of the few translucent materials that is fire rated for roof coverings. Generally it comes in 6' widths and lengths can be customized. Thicknesses vary as well, with thinner sections coming in rolls. Pieces can be seamed together and attached down with grommet screws.

Thanks very much!

Would that plastic bend to fit an arched pergola?

Trex will, but I would not call it plastic ))

Sorry, but Trex is not polycarbonate

Taesco, Paula was asking about the COVER on top of the arbor, not the arbor itself!

Thank you Kikuchi & Kankel! Good to know the material is flexible and could work for our arched pergola :).

If you are looking for pergola kits and arbors, we at Best Redwood can work for you! We manufacture and ship nationwide Pergola kits that are preassembled and delivered with everything you need to re- assemble. Feel free to contact us for a quote...

The question (I started it) was about the clear cover on top of the pergola -- not the pergola. The two of us who asked questions were talking about the polycarbonate. We were not asking for a sales pitch for pergolas or Trex. I appreciate that my question was answered by the architect clearly.