When that happens it is generally caused by mildew algae mold or dirt stains.
Cleaning stains off roof shingles.
There are several products on the market specifically designed to remove algae stains from roofs such as wet forget outdoor.
Use a garden hose to rinse the stains and cleaning solution from the roof.
Using shingles that have been treated with algicide keeps the growth at bay for about 10 years thus the 10 year algae warranty.
Set the garden hose on the spray setting with the highest pressure water and hold the nozzle close to the shingles when rinsing.
It is not uncommon for roof shingles to turn black over time.
The amount of cleaning agent you ll need to use depends on the number and size of the asphalt shingles you wish to clean.
Algae stains can be removed by cleaning though they usually return.
You can identify asphalt shingles that need to be cleaned by looking for black green or blue stains.
So it pays to clean your shingles as soon as you spot algae growth.
The worst part is old or already loosen up shingles can blow off from the roof with too much pressure.
While an occasional cleaning might not harm your roof repeated use of harsh chemicals or the erosive effects of pressure washing can damage or shorten the life of asphalt shingles.
Tim asks how can i clean the black stains off my roof and keep them from coming back your stains are probably caused by the airborne spores of a blue green algae.
Read on to find out how to remove them.
To learn how to prevent moss and algae from getting on your shingles keep reading.
This will remove any stains that were loosed up by the oxygen bleach.
For deep stains let the roof dry then reapply the cleaning solution and rinse it off again after no more than 30 minutes.
Allow the oxy bleach mixture to sit on the shingles for about 15 minutes.
But once the algicide wears off your roof hosts an all you can eat buffet for the neighborhood algae spores.
Generally the more shingles you want to clean the more cleaning agent you ll need.
After 15 to 20 minutes rinse the solution off with a sprayer that has enough force to dislodge algae and moss without damaging the shingles.
While doing little harm to your shingles the black streaks caused by the algae are unsightly.
Chances are the granules will get loosened up making those thin and brittle.
Roof shingles are exposed to a lot of wear and tear as extreme heat sun wind and precipitation come into contact with them.