The main reason to clean a roof with black algae stains is for appearance. While it can be argued that a heavily algae infested roof will or won’t experience a shortened life span simply because of the algae, few can argue that it’s ugly and this alone is reason enough to have it cleaned. However, algae is not the only thing to be concerned with as moss and especially lichen, will certainly cause shingle damage. When allowed to grow unchecked, both will root into the shingles and lichen will literally eat into the shingles, leaving spots that look very similar to hail damage. Generally, moss and lichen take longer to establish on a roof than algae, but when algae is visibly present they are not far behind and many times, even when lichen and moss are well established they can be hard to spot from the ground. Considering that Shingle Brite’s process for eliminating these infestations costs around 5% of replacement cost, it is a very cost effective way to maintain a beautiful roof and can extend the life for many years, even decades versus one that is neglected.