Polycarbonate vs PVC roof sheeting
Some have argued that it is better to use PVC (another thermoset) than polycarbonate, because it is somewhat cheaper or similarly priced to polycarbonate. PVC was used for industrial rooflight applications in the 1970s and 1980s, but has poorer impact resistance and weathering performance than other alternatives. PVC roof sheeting will not meet the non-fragility requirements without the addition of extra safety measures in the rooflight construction. It is now used very rarely in industrial or commercial applications, although it is popular DIY material in the USA. It is not expensive, has a reasonable strength-to-weight ratio and is straightforward to work with, thereby deserving its success as a DIY material for small, low-rise domestic projects.
But unlike polycarbonate roofing, PVC deforms or fades easily. Polycarbonate roofing has a much higher softening temperature and is not affected by weather impact.
There are also concerns over the environmental impact of PVC, that may in some instances release harmful toxics when it degrades. There are also concerns over the environmental impact of PVC plants. In fact, Greenpeace has labelled PVC as the “poison plastic”. In America, there is a PVC free pledge being circulated and promoted to companies to remove PVC from their supply chains and products.