If you have a consistent problem with mold growth on your roof consult a roofing professional.
Cleaning moss off shingle roofs.
The concentrated jet will scrape off the small pebbles on top of the shingles and reduce their water repellency which will only make your mold situation worse.
Hose off and brush all moss loose from your roof shingles.
You can try brushing off algae and moss with a brush or broom with medium stiff bristles but don t scrub too hard.
In the seams use the sharp edge of the scraper like a dental pick to force out the moss.
Apply liquid cleaners with a hand pump sprayer or with a pressure washer on the lowest setting so as not to cause any damage to the shingles.
Climb up to the roof and begin scraping off dead moss from the shingles using a putty knife or painter s 5 in 1 tool and working from the bottom up.
Never use a pressure washer to wash or rinse shingles.
Carefully place a ladder near the area of moss growth and don slip resistant shoes old clothes rubber gloves and eye.
Use the tool to gently lift away matted moss that has gathered on the flat sections of the shingles.
Before applying a moss remover cleaner use a scrub brush 3 15 the home depot or a long handled soft bristle brush to gently scrape or pluck moss from the roof shingles or tiles.
If chunks of algae or moss or heavy stains remain on the surface after rinsing let the roof dry then spray on the bleach solution again.