How to clean Cement Tile roof?

Question:I have a cement tile roof. How do I walk on the roof properly so I don't crack tiles? Do I walk on the peaks of the barrel tiles, or in the valleys? Additionally, what is the best way to clean the tiles? Should I pressure wash them, or use a light bleach solution to do this? (Or combo of both?) It seems most of the 'crud' on the roof must be mildew/mold.

Answers:
KL, avoid walking on the roof top if possible. Bleach and water 1:5 is a good starting point. You may want to use a
general purpose type cleaner.409...etc. Use a bio-degradeable solution to avoid damaging your lawn. Presure washing is an effective process however... do be careful not to force water up under the tiles. 2500 psi should be more than enought to remove mildew. Avoid using acid cleaners the overspray can pose heatlh risk and damage lawn.