Q: I have a 12 year old white asphalt shingle roof with a lot
of dark staining from the leaves of the nearby oak trees.
Is there anything I can do about it?
A: Your question about discoloration on your roof is a good one
that we hear a lot.
There is no recommended solution for “oak” stains. However, according
to the MSA (Master Shingle Applicator) manual published by Certainteed
Roofing Products, the following is suggested for fungus or algae and
should lighten oak leaf discolorations.
* Mix a solution of 1 part chlorine bleach, 3 parts water, and a
pinch of TSP (Tri-Sodium Phosphate.) TSP can be purchased at most home
improvement stores. Before applying the mixture you may also want to
cover any plants or shrubs around the perimeter of your home to avoid
damaging the foliage.
Apply this solution gently to the surface of the roofing, being
careful to avoid damage to other parts of the building and its
Avoid scrubbing as well as other physical contact with the roof
because the friction may loosen and remove granules that coat the
surface of asphalt shingles. Work from a ladder whenever possible,
or use “walkboards.”
Finally, rinse the bleach solution from the roof by gently spraying
the surface with water.
Observe all possible safety precautions when working on or near the
roof. Besides giving special attention to ladder safety, be advised that
the solution application and rinsing process makes the surface of the roof
slippery and therefore hazardous on which to walk.
The effectiveness of the cleaning and bleaching techniques is temporary,
and discoloration is likely to recur.
CAUTION: High-pressure washing systems for algae removal should be used
only by reliable professionals because incorrect application can result
in removing granules and shortening the life of the roofing system.
This information is brought to you by Will and Kathy Babin of Superior Roofing in San Antonio, TX.
If you don’t have the proper ladders or walk boards and/or decide it is
too risky to climb on your roof, you may return to our site at:
http://www.servicemagic.com, type “Find a Roof Cleaning Service” into
the search box and submit a service request so we can match you with the
ideal service professionals in your area.