You should not clean roof shingles if the roof has damage like missing shingles or low spots where water may accumulate. You should focus on repairing the roof before any cleaning process occurs. If you notice roof damage as you’re climbing on the roof to clean it, stop immediately. Call a roofing pro to make repairs. Cleaning a roof that has damage could lead to pooling water or water damage to the roof decking. The roof cleaning process removes mold and mildew, making the roof look better. It is not going to fix physical damage, though.

Yes, algae-resistant shingles will prevent algae and moss growth, providing double protection for your roof and roof flashing. The copper-infused granules on algae-resistant shingles release copper ions that inhibit plant growth in general, so moss will have a harder time growing on your roof, too. Keep in mind that copper ions flowing off your roof during rainfall can also inhibit plant growth below, so your gardens and grass may be affected.

You can rinse your solar panels in some cases. For example, periodically rinsing your solar panels can remove light debris if you live in an agricultural or dusty area. Light dust and dirt won’t affect efficiency much, but they can build up and mix with other debris like animal droppings, leaves, and small sticks. 

The average cost to clean a roof is around $500, but prices can fall between $150 to $1,000 or more. The size and complexity of your roof are the most significant cost factors, as larger roofs and those with various bump-outs and gables will increase your cost. Your roof material will also make a difference. An asphalt roof will require more labor, as your professional will need to be careful not to damage the shingles. A metal roof can stand up to more intense scrubbing and shouldn’t take as long to clean.