The most common type is known as gloeocapsa magma also known as blue green algae.
Black mold on slate roof.
Slate is a sedimentary rock with miniscule layers that easily cleave.
At best slimy black mold deposits are an eyesore.
Those that tend to be the most humid furthermore they will only appear on the north side of the roof.
That s why if.
The black streaks are also known as black algae or roof mold.
Once turned into roofing material slate absorbs water and can naturally de laminate during the freeze and thaw cycles of winter.
Although these dark spots and ugly black streaks on your roof may look like dirt mildew soot or mold what they really are is algae.
Slate is one of the most durable and popular materials used in construction.
What are those ugly black streaks on my roof.
This quality is what distinguishes slate as a suitable roofing material.
Commonly found in climates with warm humid summers it does no damage to the roofing but it certainly does looks bad.
Just because you can t see it however doesn t make it any less dangerous.
For this reason it works as well on a tiled roof as it does on a bathroom floor.
Like all tile however slate can be prone to mildew and mold particularly if it is installed in a high moisture area like a bathroom a basement or a kitchen.
Technically the black streaks on roofs are a form of algae known as gloeocapsa magma.
The black mold like stains and streaks that appear on roofs particularly light colored asphalt shingles is actually a blue green algae gloeocapsa magma.