Dirty Roofs caused by black streaks, moss and lichen

Black streaks making the roof dirty

I have noticed this past summer that more and more roofs are becoming covered in what is commonly called black streaks. Dirty roofs, is what many home owners tell us when they call. Sometimes they describe it as being dirt, smoke from jet fuel and staining from leaves. Not knowing the answer to what is causing the black streaks on the roof can lead to all kinds of guesses. Those ugly black streaks are caused by a bacteria, Gloeocaspa magma, which if left untreated can cause damage to the shingles.

Moss growing on the roof

roofs that have moss on them should be taken care of as soon as it is noticed. The one thing that moss does is grow at the edges and under the shingles. Then when it rains the moss absorbs the moisture and can lead to leaks in the roof. If the moss can also lead to damage of the shingle by displacing granules from the surface of the shingle.

Lichen on the roof.

This is the real threat to asphalt shingles. These little pests are often hard to see, until they colonize and then show up as big globs of green or orange on the roof, making it look like you have a dirty roof. In almost all case I have seen, if you have black streaks, and they have been there for a couple of years, you will have lichen. Lichen have root systems that go down into the shingle, and dislodge the granules under it. they will leave a roof pock marked, and open to water infiltration if not taken care of.

Roof Cleaning

There is a way to remove, and prevent these damaging, invasive species from ruining your roof. That is by having your roof cleaned with a softwash method, using the proper detergents to clean the dirty roof. A pressure washer should never be used to clean asphalt shingles, as the pressure, even if set low can damage the soft shingles. Our softwash method not only cleans, but it retards the growth of bacteria, moss and lichen for at least 3 years.