Central PA Roof Cleaning

 What Causes Ugly Roof Stains?

Most roof stains are caused by the growth of algae, lichen colonies or moss that feed on organic matter frequently found on roof surfaces. The portions of a roof that receive the least amount of sunlight are more likely to have roof stains. This explains why some homes may have roof stains only on one side of the roof, typically the northern and/or western exposure or in heavily shaded areas.

       

LICHEN COLONIES
 
Lichens are a fungus, usually of the class Ascomycetes, that grow symbiotically with algae, resulting in a composite organism that characteristically forms a crust like or branching growth on shingle granules.  Lichens put out root-like tentacles that penetrate deep into the shingle’s organic, oil base for nourishment, eventually ruining them by creating dark spots, or pock marks where they grow. It's extremely important to have lichen colonies removed professionally to stop the damage in its tracks and prolong the life of your shingles.

       


             

ALGAE
 
Algae is a living organism that thrives on dust, pollen, and the organic materials that make up the roof. Dampness triggers its growth. Stains are usually more prominent on northern and western exposures and in heavily shaded areas. Algae grows on, under, and behind the tiny granules that cover the shingles. This results in unsightly stains and streaks on the roof. Heavy algae on roofs can super heat the attic resulting in higher home cooling costs as well as reducing the natural life of your shingles.

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MOSS
 
Thick moss growth with its shallow root system keeps the roofing materials damp  for extended periods of time and this moisture promotes wood rot and can and does erode the asphalt shingles. Moss typically starts to grow at the top of the vertical slots between the shingles. These areas of asphalt shingles are the last place water evaporates from a roof. Moss, like lichen colonies, is quite damaging to shingles and some of the granules underneath the moss may be gone. This will be evident if once the moss is removed, the portions of the interior mat of the shingle are visible. It's important to have moss professionally removed from your roof in order to extend the life of the shingle.

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