Polycarbonate is a tough, clear thermoplastic polymer with a higher deformation temperature than PVC.
Polycarbonate is manufactured with a co-extruded UV resistant top layer, which will resist weathering, but its durability depends on the thickness of the top layer.
Profiled polycarbonate sheeting has a limited spanning capacity and requires greater provision for expansion than GRP. It is available in thicknesses from 0.8 mm to 1.5 mm but is only available in a limited range of profiles.
Flat multi-wall extruded sheets with one or more air gaps have a thinner wall thickness but derive their rigidity from the shape of the profile. They are limited in spanning capability, but come in wide sheets, fixed into proprietary extrusions, and are suitable as continuous barrel vaults and as double skin roof lights.
Surface coatings provide different levels of durability, chemical resistance and weather resistance.
Polycarbonate sheets must not be fitted above sprinklers as they can drop out in a fire and interfere with the sprinkler's function.
Draft Clause: