It's funny how you didnt noticed those horrible looking black streaks that had seemingly appeared and attacked your roof till I mentioned it huh? If these same stains were on your cedar siding would you put up with them for a moment? you will soon noticed that it was not just your home that is plagued. Most of the homes in your neighborhood also have these ugly black stains on their roofs.
Here Is Some info to consider: Roof Stains 101
The most common culprit causing these unsightly stains on asphalt roofs is a blue-green algae called Gloeocapsa Magma. Over the past 25 years this strain of algae has become hardier and has migrated to less humid environments. It has now become a common sight on asphalt roofs across 80% of the United States. The unsightly growth usually occurs on the north or west side as well as shaded areas of the roof. As the algae grows and decomposes, it holds moisture, which accelerates its growth.
A Change For The Better?
Another factor contributing to the growth of this problem is the change that occurred about 30 years ago in the way asphalt shingles were manufactured. In the early 70's manufacturers began using a fiberglass mat. Previously they used an organic mat made of felt or other organic base composed of various cellulose fibers. The mats are saturated with an asphalt coating and surfaced with weather resistant mineral granules.
With the use of fiberglass mats, and higher oil prices, came the use of calcium carbonate (finely crushed limestone or marble dust). It was added to the asphalt coating as a filler or extender.
Algae's Favorite Snack Food
Unfortunately, limestone is a favorite food source for this strain of algae. Do you have any buildings made of limestone in your town? If they've not been recently cleaned, you will likely see black stains caused by this same algae on the limestone. Often, these black or dark brown stains are mistakenly thought to be dirt, tree droppings, mold, fungus or mildew. Actually they are caused when the algae begins to decompose.
Algae growth on roofs occurs to varying degrees in all regions of the country, especially those subjected to warm humid conditions. Nearly all types of roofing are susceptible to staining and discoloration. It is, of course, most visible on lighter colored roofs and less visible on darker shades of roofing.
There are other types of fungi and algae that can cause staining, like green stains sometimes seen on roofs. However 99% of roof stains are caused by Gloeocapsa Magma. In some parts of the U.S., moss build up is a problem as well.
Your Stained Roof Can Look New Again, Last Longer, And Save You Energy Cost
PROVEN FACTS ON ASPHALT ROOF CLEANING
There are three major problems associated with biological attack on asphalt roofs- appearance, shortened roof life, and increased energy cost. Algae and fungi growth on roofs may also contribute to allergies.
Is Your Roof An Eyesore?
Roof stains caused by algae attack start out as areas of light discoloration then turn to unsightly black or dark brown streaks. If not stopped, the entire roof will become an even worse eyesore as the algae continues to grow and deteriorate. These ugly roof stains detract from your home's curb appeal, pride of ownership, and may affect its resale value. Realtors almost always recommend removing these unsightly stains from your roof before listing your home for sale.
A Clean Roof Will Last Longer
Biological attack from algae can cause damage to your shingles and shorten the life of your asphalt roof. The algae take root on the surface of your shingles is helping to dislodge the protective granules. Surface temperatures are also increased because of the dark stains. Its growth holds water on the roof's surface which also intensifies the sun's ultra violet rays like a magnifying glass. The increased moisture and UV rays work to further dislodge the protective granules and attack the shingle's protective asphalt coating. Moisture, UV rays, and thermal movement from temperature extremes are your roof's greatest enemies. All three are intensified by algae growth. It can suck the life from your asphalt roof leading to earlier than necessary roof replacement.
Keeping Your Roof In The Dark Can Increase Your Energy Costs
Roofs darkened by algae growth can increase cooling cost by as much as several hundred dollars a year. Measuring the surface temperature of dark, algae stained areas, versus unstained areas on the same roof, reveal that surface temperatures are increased by as much as 10%. In parts of the country where the cooling season is equal to or longer than the heating season, lighter shades of asphalt roofs are often used to lower cooling costs. More energy is needed to cool your home as roofs grow darker from biological attack.
Is There An Un-Healthy Fungus Among Us?
Algae and most other forms of fungi reproduce from tiny airborne spores. Like most plants, these spores will grow wherever they find minerals, moisture, warmth and light. Having an algae garden on your roof spewing off millions of microscopic spores around your home is not ideal, especially if you or a loved one suffers from allergies.
Pressure Washing "DO NOT PRESSURE WASH YOUR ROOF" it will void the manufactures warrenty
Some roof cleaning companies will use a pressure washer to speed the rinsing process. Even though they claim to turn down the pressure, use a wide tip, and hold the tip higher above the surface to avoid damage, they are still blasting the surface with 200-300psi of water pressure.
Asphalt shingles are not designed to withstand even that much, so-called low pressure, and permanent damage may result. A good stiff rinse is needed to remove algae colonies and their root systems, but it's best to avoid the use of power washers.
WE Now offer power washing services as well: concrete,stucco,dryvitt,vinyl siding,gutters,decks