Can those ugly black streaks on my roof be causing
health problems for my family?
According to Dr.
Victor H Morgenroth, who is a semi-retired adjunct
professor of neurology at University of Michigan, it
very well could be.
Here is an excerpt
of an article that he wrote on roof stains.
Having your roof
cleaned actually makes sense. It
isn’t just aesthetics. While people like to say that
dirty roofs lower a property’s value and may make it
hard to sell, the “dirt” on a roof actually shortens its
life span and can even present a health hazard.
Furthermore, the “dark stains” on a roof act as a sponge
to absorb the sun's heat, which causes a rise in the
temperature inside a home or building, creating higher
air conditioning bills.
dirt isn’t just dust – It’s alive. Some of the black or
very dark roof stains are caused by a resilient type of
magma(a type of blue-green algae commonly
found in climates with warm, humid summers). The algae
grow in standing water, as well as in our lakes and
ponds. The algal spores are carried to our roofs from
the water sources by the wind and birds, and then from
roof to roof where it grows and feeds on the limestone
filler in asphalt shingles and the real dirt on tile
roofs maybe in some cases the tiles themselves. Worse
still, as the algae grow, they retain water and foster
the growth of other roof inhabitants.
black stains are also very likely to harbor a number of
molds or fungi. Unlike algae the fungi on our roofs
lacks chlorophyll. They are unable to manufacture food
from raw materials. So, it must get nutrition from some
form of organic matter. To thrive, these heterotrophs,
who used to be called saprophytes, also require a warm,
normally begin their life cycle as an airborne spore
that settles on roofs, especially the asphalt-shingle
ones. The spores on the northern exposure of the roof
stand a better chance of survival because that portion
of the roof is the last part to dry after a rain or
morning dew. This raises the humidity on the surface of
the shingle, thus creating a perfect feeding and
used in roofing is fossilized, dead organic matter --
and an important food source for fungi. Asphalt, at the
granule base, is normally consumed first. Once these
granules dislodge, accelerated deterioration will occur.
Ceramic granules represent the outer hard shell that
protects against hail and other falling debris. Ceramic
granules protect against damaging UV radiation and
insulate the roof against extreme heat. So you can
understand that their dislodgement by the growing fungal
colonies can be detrimental to our roofs’ longevity.
Surprisingly, the blue-green algae are also food for the
not all mold (fungi) and algae pose a health danger,
some are harmful, especially for us older folks, younger
children and people who suffer from asthma and
respiratory problems. Their spores, which are on your
roof, can get inside your home because they end up on
the driveway and walkways from rain, and are easily
tracked inside. They can even be drawn into our air
conditioning systems and eventually populate our ducts.
Different mold species can have varying health effects,
but it is important to remember that any excessive mold
growth needs to be taken care of, regardless of the
species. Any excessive mold growth can lead to increased
allergies, toxicity, and house/building structural
If your roof is
experiencing the above referenced problems,
Please call Qwik Roof
Cleaners, Louisville Kentucky for a free no obligation
roof cleaning estimate.
well-being and health may depend on you calling today!