Black streaks on your roof shingles or black streaked shingle are caused by what is commonly known as Gloeocapsa Magma, or roof algae, or sometimes it is simply referred to as moss.
When this roof algae or moss gets attached to your roof, it starts feeding on the dead organic filler that is used to manufacture your shingles.
Once this algae or moss gets on your shingle roofing you will soon find that your shingles will begin to deteriorate and crack if they are not immediately taken care of.
These black streaked shingle are more common on standard tar shingles that are usually made of fiberglass. To clean this type of roof you should use oxygen bleach or sodium percarbonate, and always spray the seo consultant london water down the roof and not up the roof, as this can cause water to get under the shingles and cause it to leak into your house.
Never use chlorine bleach for cleaning your black streaked shingle roof because it can be very harmful to your roof and guttering and although it will clean the surface of the roof, it will not however kill the growth of the algae.
You should also avoid using a commercial pressure washer to clean your black streaked shingle roof because although it will remove the stains, it will also be removing the surface of your shingles and can do severe damage to the roof.
After you have removed the stains from your roof you will have to check to see whether any of your shingles were damaged in the process and replace any that appear to have cracks or curls.
It is highly recommended that after you clean your black streaked shingle roof and repaired any cracked or curled shingles that you use an large, moss preventative product, (commonly known as a single guard) to keep the stains from returning.
Spray & Forget TM is a highly recommended product for this purpose as the name implies you just spray it on and there is no need for you to rinse it off, which makes your task so much easier.