San Antonio Roofing: Article About Identifying Those Unattractive Roof Stains
For a homeowner, there is probably no roofing problem more vexing than a large stain. San Antonio roofing contractors commonly see problems with algae and mold growth and can advise homeowners on the steps to take to remove these unsightly stains.
Shingles may stain for several reasons. A process called extractive bleeding can occur on asphalt shingles. This process causes black streaks to run downward from the roof line or from some particular point on the roof. This black streaking is usually a sign of a defective asphalt shingle product.
The chemistry of the shingle can allow the black pigment from the asphalt to leech to the surface. Extractive bleeding can also occur with paints and finishes used on wood shingles. Manufacturers consider this a mere cosmetic defect that typically cannot be cleaned away.
Black or green algae growth most commonly occurs on asphalt, clay and concrete roofing tiles. Even slate is sometimes affected. Algae will affect the roofing tiles in a more uniform fashion that the streaking common to asphalt bleeding. Areas with more shade will be more affected. Although the discoloration may appear black, the stain may be a type of green algae.
Have a question regarding commercial roofing or insulation? Please ask any of the expert roofers from Tony's Roofing of San Antonio.
It is often mistakenly identified as a fungus or mildew, and a microscopic analysis of the material will determine the particular cause.
It is generally not true that algae causes a significantly reduced shingle life, nor will it cause health hazards by releasing harmful spores to persons living in the home. If leaves, pine needles or other organic debris are allowed to collect and remain on the roof, there is commonly a uniform brown or black staining called "debris stains." This decaying material may encourage the growth of algae, fungi, lichens or moss. These will, in turn, hold water on the roof's surface, which prevents proper drying and can lead to moisture damage.
Sometimes, an upper gutter that spills onto the lower roof will produce white, tan or other stains, depending on the specific metal. This configuration may result in early wear.
When installing roof for a new home or replacing an existing roof, it is important for homeowners to consider that these defects might affect the roof at some time in the future. Selecting the right roof materials and keeping up with proper maintenance can save years of aggravation.
It is essential that the particular cause of the roof staining be correctly identified to safely and effectively address the problem, if possible. With the exception of debris removal, algae and moss removal is a job for an experienced roofing professional.