But it is half a days work Tony.
If you are on the glass 2 hours you then have to drive there, set up and pack away and take at least some thing extra such as detergent or stiffer brush. You always have to do the sides as well.
Add to that it's always harder work than w/c and so it feels like more!
In my book that 2 hours becomes three in total and I only work 6 hours a day generally!
I have just made a decision to charge properly for conny roofs.
Except for the smallest of lean-to's I reckon £50 is a starting point for an existing customer and £75 for a non-existing.
Any sign of "green algae" and it's more.