For the best chemicals to clean a metal roof, stick to gentle detergents such as dish soap, laundry detergent, or car-wash soap mixed in a diluted solution of ¼ cup of soap to 1 gallon of water. These mild cleansers are safe for most roof finishes but are still strong enough to remove remaining dirt particles. Chemicals like bleach or acids can damage your roof, poison landscaping and grass, and pose a hazard to you and your family. If your roof is very dirty or you think it requires chemical cleaning, call a roof cleaning professional.

If you wish to forego painting your shingles but still want to give them a fresh look, a deep cleaning is the first step. Clean off any debris from your roof and gutters, and then power wash your shingles to get grime and algae off. To take things one step further, you might even consider installing new gutters to give your home a bright new look.

No, you should not pressure wash or power wash roof shingles, including asphalt shingles. The high water pressure from these machines is too strong and can damage the shingles by forcing water underneath, loosening their adhesive, and causing them to fall off. A safer and better alternative is soft washing with a pump sprayer. To ensure the job is done safely without causing damage, it is best to hire a local roof cleaner.

Clean the outside of your home at least once a year. If you live in an area with salty sea air, high levels of pollen, or an abundance of leaves in the fall, it's helpful to wash it at least two times a year. Frequent cleanings will allow you to remove debris and pests before they flourish into infestations, or cause mold and mildew.