Conservatory rooves is a matter of how soiled and access you have. I had two this week the one was bad with leeches on the plastic sheets but goo access took me 1.5 hours The second but did not seem bad. just a bit of moss with access from one side which took me 4 hours. So I lost on this one time wise. One needs to be careful. I will be using a pressure on this infuture. And don`t tell me you will blow the seals. If you work down with the flow it won't. I would say 90 for a quick clean thats 1.5hours work to 120 for a longer clean is about right. Unless they are large connies.