Prevention is always the best option for dealing with roof algae.
Roof algae control.
Increase the amount of sun on your roof by trimming back overhanging branches.
It works with any wood or composition roof.
4 7 out of 5 stars 142.
Clean the roof off periodically using a stiff bristled broom or spray of water from a garden hose or high pressure sprayer removing the debris that traps moisture against the roof and encourage moss.
Common algae that form on roof surfaces including asphalt shingles and roll roofing include the algae shown above and gleocapsa magma a species that generally appears black on the roof surface but under some lighting conditions even on the roof gleocapsa magma can appear as a blue green color as might other algae genera species.
You cannot control whether the wind deposits spores onto your roof but you can prevent the spores from developing into algae.
Zincshield pure zinc strip to avoid ugly roof stains from moss algae fungus and mildew 50 foot roll 2 5 includes bag of zincshield nails made in the usa.
To keep the algae from coming back insert 6 inch wide strips of zinc or copper under the row of shingling closest to the roof peak leaving an inch or two of the lower edge exposed to the weather.
The natural action of rain water time releases zinc carbonate a proven fungistat which then washes down the roof preventing destructive roof moss algae and fungus growth.
That way whenever it rains some of the metal molecules will wash down the roof and kill any algae trying to regain a foothold on your shingles.