If you have noticed the incredible outbreak of roof stains in your Pennsylvania area neighborhood, you’re not alone. Roof stains
are sweeping the Country from coast to coast especially in the Pennsylvania area. Until recently, most of us thought the stains
were just ugly. Ugly yes, but there’s more to the story!
Fact: Up to 90% of the homes and businesses in Pennsylvania will develop some type of problem caused by ugly roof stains. The
reason? Shingle formulas have changed dramatically over the years. As a result, your Pennsylvania area roof will show signs of
streaks and stains very quickly. Shingle manufactures didn’t intend for this to happen. Few saw it coming until it was too late.
Recent studies prove that shingles, wood shakes, even barrel tile can be damaged from roof stains. Until now, this wasn’t
fully understood. Replacing the roof will not solve the problem. The stains come back again very quickly. New shingles take
far less time to become streaked!
Until the formula for shingles changes, Pennsylvania roof stains are here to stay. To combat this problem most manufacturers now
make stain resistant shingles. These products are expected to look good for up to 10 years. You should read the fine print
carefully before installing them. *In some cases, these new resistant shingles can damage your gutters, down spouts, valley
flashings, etc. Here’s why: They contain large amounts of copper. Copper leaches from the shingles, collects in gutters, and
corrosion results. This phenomenon is called electrolysis. Fact: 98% of American homes have gutters made from zinc,
aluminum or tin. These metals are incompatible with copper. Unfortunately, corrosion damage is not covered in the shingle
warranty. Ask the manufacturer for more information.
The recent housing boom will add a blizzard of complaints for shingle makers, and unfairly the people who install shingles for
a living. Fortunately, the cure for roof staining is affordable, and if caught in time it’s very easy to treat. We would not dream of
replacing vinyl siding, decks, carpet, concrete or fencing just because it got dirty. We clean these surfaces regularly. Now,
any roof can be safely cleaned and protected using Roof Cleaning Pros & Pressure Washing of Pennsylvania
HOW CAN IT BE CLEANED?
Typical roof cleaning methods involve either pressure cleaning or chemicals solutions containing Chlorine Bleach or Sodium
Hydroxide. If used properly, these methods will clean the roof with minimal adverse impact – but the effects can be very
temporary and will generally have to be repeated every 6-18 months in order to maintain the appearance of the roof.
WHAT IS THE BEST CLEANING METHOD?
Each method has its advantages and disadvantages.
A chlorine and water solution can be used followed by a thorough rinse. Of course, since chlorine can be toxic to people and
plants, proper care should be taken to protect employees and the surrounding property from overspray and runoff. The
benefits to using chlorine include a much faster cleaning process and minimal rinsing as compared to the other methods. This
translates into much less wear & tear on the roof – particularly asphalt shingle roofs.
Sodium hydroxide based cleaners are generally advertised as safer for the landscaping, but sodium hydroxide is caustic, very
toxic, and care should also be used to protect employees and surrounding property. Sodium hydroxide is also a very effective
de-greaser. So high levels of sodium hydroxide in a cleaning product can cause damage to an asphalt shingle roof that can
be irreversible. These products generally require much more rinsing than the chlorine method. The rinsing process is not only
time consuming, but it can also be potentially damaging to the roof if not done correctly. A quality sodium hydroxide based
product should not require any more than 100 psi to effectively rinse an asphalt shingle roof and even then some granule loss
should be expected.
Pressure cleaning is an option that should only be used on a concrete, barrel tile, or metal roofs. Pressure cleaning has the
advantage of not requiring chemicals, which eliminates some of the cost – in addition to landscaping and chemical exposure
concerns. The down side to pressure cleaning is that it is very time consuming and it exerts tremendous force on a surface
that is not really designed to handle it. In addition, repeated pressure cleaning can wear away the surface of some tiles that
are only covered by a thin layer of coloring. When this happens, the grey concrete color starts to show through and the roof
must be stained or painted.
THESE METHODS ARE NOT A LONG-TERM SOLUTION.
While these methods are relatively safe and effective when done properly, repeated use will lead to premature aging of the
roof. The natural erosion that occurs over time from the basic forces of heat, cold, wind, and rain alone are enough to weaken
most roofs to the point where annual inspections and minor repairs are necessary to prevent significant repair costs. But
when the roof is repeatedly subjected to high pressures or harsh chemicals, the aging of the roof structure is significantly
accelerated. With repeated cleaning, tiles are more likely to shift, slip, or break and asphalt shingles are more likely to
become brittle and crack. When this happens, there is a greater likelihood of tearing the roof membrane simply by walking on
the roof. Once gaps are created in the roof and subsequent pressure cleaning or chemical cleaning takes place, these gaps
provide the water or caustic solutions a path to the roof membrane and increase the chance of costly roof leaks.
Why does my roof look so bad?
Pollution, trees, and jet exhaust are the first thing customers think of when they see staining on their roof. They are often
surprised to learn that the problem is almost always a growth, such as algae, mold and fungi, which feed on the minerals
within the asphalt of their shingles.
Shingles today are made differently than the shingles of just 15-20 years ago. Shingles in the past were made up of a thick
cellulose (paper) mat, saturated with asphalt, and toped with granular. Most shingles had an expected life span of 20 years.
Growth didn’t occur on these shingles until the latter part of their life span because the oils would continually leach to the
surface, preventing growth. In the final years, the oils would become mostly dried and dissipated, and growth would begin. It
was often in the form of deep rooted systems, such as those in the family of fungi commonly referred to as moss.
Most shingles today are made with a thinner layer of asphalt, separated in the center, by a dense layer of fiberglass. Oils do
not pass through the layer of fiberglass. This is good for the bottom layer of asphalt. It protects this layer from degrading, and
helps shingles last longer. However, the top layer of asphalt is very thin, and does not benefit from leaching of oils from the
bottom layer. In a short span of time, this top layer loses its oils though weathering and evaporation, leaving the remaining
organic matter vulnerable to all sorts of growth. The dense layer of fiberglass prevents most deep rooted growths, so most
are single cellular in nature, thus creating the look of a stain.
Will this problem damage my shingles?
Yes. The type of growth you have determines the amount of damage. The least damaging are the algae and molds. These
growths hold moisture, which very slowly causes premature degrading. The worst growth we encounter is lichen. We find it
growing on roughly 30% of the roofs we clean. Lichen is such a hardy feeder, it creates enough damage to the roof, in as little
as 3 years, so as to cause granular to fall off.
Customers often forget the visual damage growth causes to their roof. Most roofs are replaced today due to the way they
look. We are finding many people are replacing their 25 year roofs in as little as 10 years because they look so bad. Often a
roof cleaning is all they need.
What about fungi resistant shingles?
Shingle manufactures have recently begun marketing shingles as algae and fungi resistant. They achieve this by baking a
micro thin layer of copper sulfate on the outside of roof granular. Every time it rains, the copper releases ions, which tend to
kill growth spores. However, such manufactures warranty the effects for only 10 years; where as the shingles are warranted
for 25-50 years. As the copper sulfate becomes weathered away, the shingles begin to develop growth. Eventually, even
these shingles will need to be cleaned.
Why do most roofs have growth on the North side?
Ultra violet rays of the sun kill most growth spores from algae, mold, and fungi. They also rapidly dry the surface after a rain,
making it impossible for them to feed.Website
What can be done to prevent growth after a roof is cleaned?
In the past, copper and zinc strips, installed on top of the shingles along the ridge, were the only long term preventative
available. Not only did these methods not work well, but they also had a very short effective period; especially in the case of
There are now products which come in liquid form that can be applied to the roof shingles to prevent re-growth. Keep in mind,
these products will not clean an already infected roof. They will simply help prevent re-growth. As with the copper and zinc,
these products need to be reapplied about once every 4-5 years.
We at Roof Cleaning Pros & pressure Washing of Pennsylvania know all of this can be a bit over whelming and confusing at the same time that is
why we are here to answer all of your questions and concerns about the proper way to clean your Pennsylvania area roof, so give
us a call and schedule your FREE on site or by phone consultation today.