Will Pressure Washing Damage My
The straight answer
If you asked if water will damage a composition roof the answer is
also yes. If you asked if direct sunlight will damage a composition
roof the answer would also be yes. All three of the above are going to
create wear and tear on your roof but not to the extent that a person
should feel concerned each time their roof is exposed to one of them. Having worked several years in the
roofing trade I often heard you should never pressure wash a composition
roof, now that I am in the pressure washing business I hear that
sentiment expressed with increased frequency. The fact of the matter is
that in most cases that is very true. I have been on many roofs where
someone preceded me with a pressure washer and destroyed every section
of the roof they had set out to clean via pressure washing. If a person
is not familiar with roofing systems and experienced with the
accessories and functions of a pressure washing machine KEEP THEM OFF OF
Now on the other hand I have yet
to hear someone who is experienced and well practiced in the pressure
washing trade express that a composition roof should never be cleaned
with a pressure washer (they all do express a need for caution). Someone who knows how to regulate the output
pressure (psi*) of their
machine can easily drop it down to a much safer working level. Knowing the
different accessories available for pressure washing is another must.
Some nozzles have an output spray which is many times more abrasive than
others. Being familiar with using a pressure washer also allows a
professional pressure cleaner to account for the angle at which the
spray is directed at the roof as well as the resulting deflection spray.
Instead of being a danger to your roof, when the above credentials are
met, having your roof pressure cleaned becomes a valuable tool in
ensuring the longevity of your investment.
The opening comment of this
article affirmed that pressure washing does damage a composition roof.
However when done correctly the advantages outweigh the risks of failing
to take action against invasive moss growth on your roof. By all means Practical Pressure strongly
suggests that you take every effort necessary to keep moss from ever
growing on your roof so that pressure washing is never needed. However at times it is necessary given the circumstances. To Illustrate:
Chemotherapy is not "good" for the human body but when cancer strikes it may
be absolutely necessary for a person to be treated with it, and many people
have enjoyed a satisfying and prolonged life as a result of accepting the
treatment. Pressure washing a composition roof covered in moss is very much
the same, though pressure washing is obviously going to produce a limited
amount of wear and tear, in
the long run it can, in large measure, actually increase the life of the roof. The effects of
moss growth on your roof can be devastating even after a relatively short
period of time. Moss often strips the protective granulated surface off of
the shingles it grows on and can even go so far as to eat holes clear through the roofing. The sooner you have it removed the longer your roof
will last. Even roofs which have been pressure washed multiple times by a
professional pressure cleaner have proved to be in much much better
condition than a roof that was left uncared for when moss began to
It is true that there are other
ways to remove moss from your roof but usually the alternative is not an
improvement over pressure washing. Some common instruments I have
observed or heard reported to have been used to remove moss are: screw
drivers, flat bars, pry bars, putty knives and wire brushes. Certainly
it could not be said that these instruments provide a less abrasive or
less damaging method of removing moss from a composition roof. It is
possible to kill the moss with out pressure washing by using things such
as granulated and powdered moss killers but even then the moss will most
often stubbornly cling to the roof and continue to hold moisture. Live or dead moss will retain water
on your roof subjecting it to decay and it will also assist in
collecting other debris to pile up on your roof.
consideration of the above factors Practical Pressure can, in good
faith, state that your roof is being well served when it is properly pressure washed by an
Looking for a New Comp Roof? May We
Please Recommend - Pritchett's Roofing
In view of the potential dangers in
damaging your roof via pressure washing and the possible fall hazards we recommend that you do hire a
professional to care for this maintenance should the need arise. Practical
Pressure has experience not only in pressure washing but has also spent
years in the professional roofing trade. We can assure you that with our
experience in pressure washing as well as with roofs that your composition roof is in
good hands with Practical Pressure.
About Algae on my Roof?
How can I Prevent Moss and
Algae from Growing on my Roof?
What About Lichen?
* PSI - pounds
per square inch
See Picture of Shingles Damaged By
See Shingles Damaged by Moss
Green State in a Clean State"
professional exterior cleaning services for the Greater Puget Sound Region of Washington State. Practical Pressure is based in Tacoma,
Washington and offers cleaning in the following cities and towns.
Lakewood, Lacey, Olympia, Tumwater, Auburn, Kent, Black Diamond,
Puyallup, Bellevue, Redmond, Renton, Tukwila, Federal Way, Milton, DuPont, Steilacoom,
Spanaway and more.
include roof cleaning (tile,
maintenance and repairs as well as moss
removal and moss
prevention. We power wash decks,
siding, gutters (we
also do gutter cleaning), and just about anything else that you may want
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