If they are severely molded you may want to give it a little longer.
Remove green mold from roof shingles.
Hose off and brush all moss loose from your roof shingles.
Start from the top shingle and rinse downward to prevent water seepage.
Though often attributed to an accumulation of dirt defective shingles mold or mildew.
The mild chemical reaction caused by rainwater coming in contact with the zinc inhibits the growth of mold and mildew.
This will prevent the solution from draining in your direction.
Removal can take several months before the moss can be blown away revealing clean shingles underneath.
Next rinse the shingles thoroughly with a garden hose at low pressure.
If you live in a humid area of the country you ve probably seen unsightly dark streaks on asphalt shingle roofs.
Step 3 applying asphalt roofing shingles containing a copper additive in their surface granules is an option.
Run your gloved hand over the shingles to check for any slimy mold remaining after you re finished rinsing.
Always keep your roof clear of overhanging branches and clean your gutters regularly.
Start from the top shingle and rinse downward to prevent water seepage.
Carefully place a ladder near the area of moss growth and don slip resistant shoes old clothes rubber gloves and eye.
The most common culprit is actually a blue green algae known as gloeocapsa magma that is spread by airborne spores.
A homemade cleaner of one part liquid chlorine bleach to one part of water can also be effective in removing and killing moss that clings to the roof tiles.
Continue spraying until you see runoff then let the chemicals sit for 15 20 minutes to soak in and begin attacking the mold.
Apply liquid cleaners with a hand pump sprayer or with a pressure washer on the lowest setting so as not to cause any damage to the shingles.
Removing moss and algae from asphalt shingles.
They will let the mixture stay on the roof for a bit to ensure it penetrates the stain.
If some remains apply the cleanser again wait 10 more minutes and repeat the rinse process.
Allow the solution to soak into the shingles for at least 15 minutes.
The bottom line preventing algae and moss from growing on your roof is easier than trying to remove it.
But outdoor heavy duty cleaning usually calls for more heavy duty mixtures such as tsp and chlorine bleach see the tsp.
The roofing contractors mix this bleaching agent with water and spray the roof down paying close attention to areas that are stained.
Start on lowest row of shingles and work your way backwards to the upper part of the roof.
Installing zinc strips under a row of shingles near the ridge of the roof will prevent mildew from forming.