What has caused holes?
QWhy do I have holes in my polycarbonate greenhouse? Clive Spate, by email
APolycarbonate sheeting is a twin-walled plastic glazing that’s resistant to breakage, lightweight, durable in adverse weather, and good at retaining heat. Quality polycarbonate sheet may have a useful life of many years. The holes in your roof panels may be due to the sun. UV stabilisers are added to polycarbonate to help protect the material from the effects of the sun but eventually exposure will lead to degradation of the material.
This usually affects just the roof panels, which can be replaced as necessary.