Do polycarbonate roofs have a protective film on them to slow algae growth down...? Reason for this question is about 3 months ago one of my regulars asked me about cleaning her conny roof, now to be fair it wasn't that bad just odd patches of green here and there, anyway priced agreed and booked in for following visit. Sent text following month to say I was going her reply ok but leave conny roof hubbies power washed it....ok by me it's their roof to do what they want with. Now I take a look at it while I am doing the windows and it looked ok not done a bad job....whether he done any unseen damage I don't know? We all no that if you don't know what your doing when power washing conny roofs you can cause problems with the seals ect. Anyway I turns up yesterday and the lady asked me if I could do the conny roof....the reason been its gone green...! I take a look and sure enough green algae everywhere, I did't have time to do it there and then so told her it would have to be after Xmas. So why as it gone green so quick..? It actually looks worse now then it did before she first asked me to do it. I am a bit reluctant to do it at all now because if this as been caused by hubbies power washing and then I clean it the proper way and the samething happens, I don't want the blame turning to me.... Any thoughts on this anyone..!!