I've been asked to pressure wash the bottom three courses of bricks around a local block of flats as in places there is a lot of algae and moss accumulating due to it not getting much direct sunlight. Questions: I have a Nilfist 1.2 pressure washer and lance so I think this would be ok as I don't want to rent/buy any equipment. Opinions? Should I pretreat the walls to loosen/kill the algae before pressure washing? If so what with? Can I damage anything do you think. The pointing looks ok to me and he bricks solid? How much should I charge? By the metre? All advice welcome as I am meeting the building manager Friday so would like I be a bit more clued up. Thanks in advance, Adrian.