What’s That Ugly Dark Stain on your Cleveland Area Roof?


That unsightly dark stain on your Cleveland area roof that is slowly creeping up and covering the entire surface can really mar the appearance of your home.
Your neighbors might consider it an eyesore. And if you have just put your house up in the market, it could really decrease your property’s value.

Yeah, but WHAT is that ugly stain on your roof?

The dark stain is usually mistaken as mold but that is actually a type of blue-green algae common in places with humid summers.
Algae poses no risk to human health but it could be contagious, which means that roofs on other nearby houses roofs may ‘catch’ it. In no time, roofs throughout your entire neighborhood can be covered in the unsightly dark stains. The algae, being tiny plants, have spores that are airborne and that is why they spread easily.
Aesthetically, it can affect your house. But more importantly, the stains could also decrease the value of your home.

What causes the growth?

It can be caused by improper attic ventilation or a bathroom fan that is vented into the attic space. However, the most common reason algae grows on roofs is because it finds moisture and food (paint, lime, etc.) there. You will notice that the stains are more concentrated in areas of the roof that are not reached by sunlight. The heat from the sun can usually stop algae growth from spreading further.

What are other ways to get rid of the algae growth?

If heat from the sun is not sufficient to retard algae growth and keep it from staining your Cleveland area roof, here are tips to remove those stains:

  • Spray the roof with a solution composed of 50% water and 50% bleach. Don’t use a pressure washer, it can damage the shingles.
  • Have zinc strips installed to prevent further algae growth. Place the zinc strips at the peak of the roof so that when it rains, some of the zinc molecules will wash down the roof, killing the tiny plants.
  • If your roof is due for a replacement, you can use new shingles laced with copper granules. Copper is lethal to algae so you can prevent growth stains from ever marring your home’s exterior.

If you are looking for a roofing, siding, storm damage, or insurance repair specialist in the greater Cleveland area then please call 440-731-8282 or complete our online request form.