Extensive mold growth can also expose the interior of your attic or crawlspace to mold spores carrying the problem over to the inside.
Cleaning mold off asphalt shingles.
A pressure washer can eradicate the moss from the deep crevices and prevent it from returning next season.
If you have a consistent problem with mold growth on your roof consult a roofing professional.
Power washing your roof will reduce its lifespan.
The mild chemical reaction caused by rainwater coming in contact with the zinc inhibits the growth of mold and mildew.
Step 3 applying asphalt roofing shingles containing a copper additive in their surface granules is an option.
For large expanses of an asphalt shingled roof use a long handled scrub brush made for cleaning gutters and roofs.
Asphalt shingles are designed to withstand rain not the force of a power washer.
The concentrated jet will scrape off the small pebbles on top of the shingles and reduce their water repellency which will only make your mold situation worse.
Do shingles on your north west or other shaded roofs have streaky moldy stains.
Never use a pressure washer to clean an asphalt shingle roof as this w ill cause granule loss and very likely premature failure of the roof system.
Generally you ll need to unscrew the tops of the spraying device and the cleaning agent fill the spraying device then.
Not to worry though because you can clean the mold off with basic household bleach and save your roof long before you need an expensive replacement.
1 4 cup tsp trisodium phosphate or other heavy duty cleaner don t use a cleaner that contains ammonia or is not recommended for mixing with bleach as it can result in poisonous chlorine gas pour the ingredients into a pump type garden sprayer mix well and spray.
Installing zinc strips under a row of shingles near the ridge of the roof will prevent mildew from forming.
But that would only make sense if the shingles were worn out.
Black streaks on the north and west facing and shaded.
In severe cases it may take more than one bleach treatment to kill all of the moss.
Let the mixture sit on the roof for 20 minutes before you rinse it off.
Make your shingles last longer.
Don t use a pressure washer to apply the cleaning agent.
How to clean roof stains wash your shingles where the sun doesn t shine.
Mold stains can form on roof shingles that are in permanent shade.
Never use a pressure washer to wash or rinse shingles.
Instead gently pray the roof down with a mix of half bleach and half water.
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.
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.
Doing so can damage your asphalt shingles.