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.
How to clean algae off roof shingles.
To learn how to prevent moss and algae from getting on your shingles keep reading.
Heavy moss growth can actually form dams that can cause water to back up under the shingles and damage the roof deck.
The most effective method of cleaning algae and moss from a roof is w ith a 50 50 mix of laundry strength liquid chlorine bleach and w ater.
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.
Simple cover your plants just as painters do.
For deep stains let the roof dry then reapply the cleaning solution and rinse it off again after no more than 30 minutes.
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.
There are several products on the market specifically designed to remove algae stains from roofs such as wet forget outdoor.
But that would only make sense if the shingles were worn out.
Using bleach is recommended by most shingle roof manufactures and the arma asphalt roofing manufactures association.
The less expensive solution is to spray wash the roof with a 50 percent mix of water and bleach to get rid of the algae.
So it pays to clean your shingles as soon as you spot algae growth.
Do it yourself and save big bucks.
It s best to clean moss off a roof as soon as you notice it s growing there.