Most roof stains are caused by the growth of algae, fungus, lichens or moss that feed on the organic material in the shingles. These organisms spread their root systems underneath the granules and if allowed to continue to grow will likely decrease the life span of the roof and cause the attic to super heat, raising cooling costs.
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 exposures or in heavily shaded areas. This is a issue we see a lot of in the Lakeville, Prior Lake & Apple Valley, MN areas and we are your best possible solution to eradicate this from your roof!