Algae colonies can form on roof shingles that are in permanent shade. These stains will discolor your roof and damage the shingles
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Algae colonies can form on roof shingles that are in permanent shade. These stains will discolor your roof and damage the shingles
Cleaning Roof Shingles from algae
Do shingles on your north, west or other shaded roofs have streaky, moldy stains? Black streaks on the north- and west-facing and shaded areas of your asphalt-shingled roof can really wreck the appearance of your home.
The streaks look like mold, but they’re actually algae colonies that form in your shingles and feed on moisture and the limestone filler agents in the shingles.
Algae colonies can form on roof shingles that are in permanent shade. These stains will discolor your roof and damage the shingles over a period of time if left alone.
In addition, some houses might have green algae from nearby trees. There is a simple way to get rid of these algae. To clean roof algae, use Oxygen Bleach. It will not take the color out of the shingles and will not harm the vegetation.
Fill a pump sprayer with one-half water and one-half chlorine bleach solution, then secure the lid firmly. Wet down plants beneath the roof thoroughly to minimize the damage that splashing bleach solution can do to them. Alternatively, cover them with plastic tarp.
Check the weather forecast and choose a cool or overcast day with little to no wind so the spray hits your shingles, not the neighbors’. Those conditions allow the cleaning solution to soak deep into the algae colonies without evaporating too quickly.
Allow the solution to soak into the shingles for at least 15 minutes. If they are severely molded, you may want to give it a little longer. Next, rinse the shingles thoroughly with a garden hose at low pressure. Start from the top shingle and rinse downward to prevent water seepage.
If you wish to prevent reoccurrence of algae and fungus, think zinc! Zinc strips have been used for many years as an algae preventative. When it rains, a slight amount of zinc dissolves from the strips and coats the roof, inhibiting algae and fungus growth.
Remember - Zinc & copper strips prevent “most” future growth of algae, moss & lichen, but they will not kill or remove the current growth on your roof.
By regularly brushing your patio over, this will remove any debris and dirt that is sitting on the surface.
Regular roof maintenance and repair is an important part of home maintenance, but is often overlooked