What Causes Stains On Roof Shingles

Black stains on an asphalt roof caused by algae.

What causes stains on roof shingles.

If you live in a humid area of the country you ve probably seen unsightly dark streaks on asphalt shingle roofs. It causes the black stains you may see on your roof. Here is a diagnostic guide to types of stains and staining materials found on roof surfaces black red green brown or other coloured stains on asphalt roof shingles or on other roofing materials need first an accurate diagnosis of the stain cause and then proper steps to remove the stain or to prevent future staining on roof shingles surfaces. Roofing manufacturers have tackled the problem of roof algae by creating shingles containing copper which is deadly to algae.

Over time this algae accumulates developing a black outer coating which causes stains on roof shingles. Light spots on roof shingles dark colored asphalt shingles may appear lighter and patchy as they age. The streaks are caused by a type of algae known as gloeocapsa magma. This article series tells readers how to identify explain the most common causes of black brown red gray green or white stains appearing on roof shingles and on other building surfaces.

It is not uncommon for roof shingles to turn black over time. And depending on the age and condition of your roof cleaning may be the most cost effective solution since it s about 5 to 10 percent of the price of a roof. Water stains if the discoloration seems to be damp check the attic or ceiling below the roof stain and investigate for a leak. Look in the gutters for signs of asphalt granules that have washed off and expect to need a replacement.

While the streaks do not cause a great deal of damage they can cause the shingle to age prematurely. Replacing the shingles on your roof just because you have black stains is not necessary however and you should be suspicious of any roofer that suggests roof shingle replacement as the only solution to your algae problem. Though often attributed to an accumulation of dirt defective shingles mold or mildew. Roof shingle stains are often caused by black algae bleed through or extractive bleeding of asphalt dirt soot or organic debris.

When that happens it is generally caused by mildew algae mold or dirt stains. Roof shingles are exposed to a lot of wear and tear as extreme heat sun wind and precipitation come into contact with them. The algae feed off of the limestone within the roof shingles. What causes those dark marks and what can be done to eradicate them.

The most common class of roof algae is gloeocapsa magma a bacterium that eats water and expels oxygen. Surface residues or discoloring stains can affect almost any type of roof. Roof experts who are highly rated by members of angie s list say the source is an algae called gloeocapsa magma. The black stains are buildups of algae that can prevent the sun from burning off the bacteria.