But that would only make sense if the shingles were worn out.
How to clean mildew off roof shingles.
One way to determine if it s mildew is to put a few drops of chlorine bleach on to the black mark.
Proper cleaning is an important step in roof maintenance.
If it is slimy or any sort of residue comes off on your hand repeat the above steps.
Allow the roof to dry thoroughly.
Do it yourself and save big bucks.
Cleaning due to evidence of permanent asphalt shingle damage caused by high pressure powerwashing.
If it s dirt the dark stain will remain but if it s mildew the stain will go away.
Some of this growth including the stains from algae spores.
How to clean roof shingles.
To clean mold off a roof start by putting on rubber gloves a breathing mask and goggles to protect yourself from the harsh cleaning chemicals.
Using shingles that have been treated with algicide keeps the growth at bay for about 10 years thus the 10 year algae warranty.
Extensive mold growth can also expose the interior of your attic or crawlspace to mold spores carrying the problem over to the inside not to worry though because you can clean the mold off with basic household bleach and save.
You could replace all the roofing with new shingles dark enough to disguise the staining or with shingles laced with copper granules which are lethal to algae.
Mold stains can form on roof shingles that are in permanent shade.
Oxygen bleach lightens stains as well and is less harmful to the environment but it doesn t produce as immediate or dramatic an effect as chlorine bleach.
A mixture of trisodium phosphate tsp bleach and water will also remove stains.
But once the algicide wears off your roof hosts an all you can eat buffet for the neighborhood algae spores.
Then use a long handled brush to scour the surface of the shingles and loosen stuck on mold while it s dry and brittle.
You must let the roof dry before a second application of mix.
That ll kill it off but won t inhibit regrowth so just rewet the roof with the bleach solution whenever cleaning off the rest of the place.
Now if you live where cleaning off mildew from exterior surfaces is a constant chore the just hit the moss with the same bleach solution.
One day you may notice that your roof is turning black or fungus is spreading across of it.
A few years ago commercial roof cleaning products containing hydrogen peroxide lye were commonly recommended to remove mildew.
These stains will discolor your roof and damage the shingles over a period of time if left alone.