We do do dat , don't we doh !
Pitch witches are OK for clean tiles! Not ones with a shagpile of moss. And you still have to go up there, to the top.....
We have tried them all, cos thats what we do at roof-coaters. (Can I add dot com to that without a fuss???)
Telescopic lances, cherry pickies, but we still go back to cat ladders, a harness

and a turbo nozzle on the end of a 30-40 mtr hose. You can never get a C-Picker to where you want it, and any attempt from the floor is asking for a face full of fuss and mush.
If you are willing to offer roof cleaning than you should offer tile replacement, ridge pointing and even coating as the real answer. Everyone knows that without sealing the tiles, you are just adding to the problem.
If you want to sub the work.... call. (web site should be obvious by now..... oops what a giva-way.
MP
