A dumb question here perhaps, why add bleach ?
I've pressure washed wood, concrete, and very dirty things. At no point did it cross my mind to add bleach, or how I would add bleach since the pressure washer is direct connected to the hose.
If you have trees you care about below an area your spraying bleach water, just pressure wash it instead.
I'm assuming you have stucco/terra cotta roof tiles because what other roofing material would you pressure wash right.
As an aside , I've never heard of cleaning roof tiles or many of the FL HOA "rules" that people have mentioned here on the board.