Roof Truths - To Wash or not to Wash...

Once again we are adding information at the request of prospective clients who need to know. With
the unusually damp weather many New England residents are finding an unusually large amount of
mold growth on their roof. As a result we have been receiving many requests regarding cleaning
asphalt roofs. The general question seems to be, "Is it necessary to power wash my roof to get rid
of the mold on it?" In most cases it was indicated that the roof has a few years on it and that the
homeowner does not want to risk damaging it with a high pressure washing.

OK. Some of our competitors will not be happy with us but the truth is this. Whether the roof is
new or old asphalt shingles* in most cases you do not need to, and we would recommend against,
using a pressure washer to eliminate mold on your roof. You can accomplish all this by giving the
roof a soaking with a blend of antimicrobial chemistry and allow a few days for the growth to
die and a few more and a decent rainstorm to finish the job for you.
 
If you feel you really must do something - if it hasn't rained adequately to rinse off your roof,
after two weeks, wash the brown residue from the dead fungus off the roof with your garden hose.

The balance of a few days for the chemistry to do it's job and nature to take it's course is by
far a safer option than pressure washing. The benefit of knowing the roof will not be harmed
has an obvious inescapable value, especially when the cleaning result is the same.

The one note we would add here is this. Many asphalt shingle roofs do get coated by chimney
soot and debris from trees. In some cases mold buildup has been ignored and is sometimes as
thick as an inch or more. The only reasonable method to clean the roof in those situations is
by a low pressure 800psi or less) pressure washing. A good blend of commercial biodegradable
chemistry applied before washing, and a knowledgable operator should yield a thorough cleaning.
A light chemical treatment after washing should extend the roof's mold resistance for some time.

*There are several materials used in construction on roofs today. We have covered asphalt shingles here only, as they are the most common roofs
in our New England area. Different roofing materials will require different treatments.

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