Dirty-roof.com cleaned this slate roof and front and rear patios last week. The 80 year old slate roof was in very good condition but was infested with moss, algae and lichen. 

The algae on the stone patios was unsafe and the customer wanted it fixed. When algae gets wet it becomes very slippery to walk on. We were able to remedy this potential hazard and restore some curb appeal at the same time!