I have a few conservatories in my area they have a drop of 15 degrees so nearly flat. I clean they every second month including the windows. The conservatories are 6 panel glass, 4 meter long so take a fear amount of time. I am in the south of England anyone doing these on a regular clean and how much do you charge for the roof only. They do often have a sand that is difficult to move so use 10 lit pump to get the pressure to move it.