Fill a bucket with warm water and several capfuls of mild detergent.
Soak the soft-bristle brush into the warm water with detergent.
Place the ladder below the gazebo roof and step up onto it to reach the top of the gazebo roof.
Hang the bucket of warm water and detergent from a hook on the side of the ladder.
Dip the brush into the bucket.
Scrub down the roof using the scrub brush and mild detergent solution.
Reposition yourself and the ladder around the gazebo to clean the entire roof.
Rinse down the gazebo using a water hose once you are finished scrubbing the surface.