Roof cleaning — one of the toughest assignments for a Westchester, Dutchess, or Putnam homeowner to face in the Fall season.  The combination of lawn maintenance and preserving your home’s aesthetic doesn’t allow much time on Sundays to catch the game. (Though if the Giants keep playing like they are, it’s not necessarily a bad thing.

The Telegraph posted a fantastic article on what you should know about the complexities of roof cleaning and why our method is both the safest and the best for removing algae and mildew.  A few snippets…

QUESTION: One side of my asphalt-shingled roof, which is shaded by a large maple tree, has small growths on it that look like the lichens that grow on trees. It also has black stains in other parts of the roof. How can I clean this stuff off and what is it? — Gary

ANSWER: The growths that look like lichens probably are lichens, which can grow on asphalt shingles as well as trees. The black stains are a fungus.

Shingle stains like these are very common, especially in areas of high humidity and on roofs shaded by trees. Unfortunately, cleaning a roof isn’t easy and it is usually not a good do-it-yourself project, mainly because roof work is dangerous, especially on wet, slippery surfaces.

The only way for a do-it-yourselfer to work on a roof with reasonable safety is to wear an approved safety harness, which can cost $50 or more, and attach the harness to an appropriate restraining system (not a length of clothesline looped around a tree).

Our roof washing clients in West Harrison, Armonk, Bedford, & Yorktown Heights, New York (as well as the rest of Westchester) don’t need to be worrying about harnessing themselves to a tree.

That’s where we come in.

Many mixtures for roof cleaning are available at home centers and on the Internet, but care should be used in selecting one. Some cleaners contain bleach, either chlorine or oxygen bleach, and some experts say bleach should be left on asphalt shingles no more than five minutes or it will damage the shingles.

Other cleaners contain sodium hydroxide, which is the chemical name for lye or caustic soda, a powerful chemical that can be hazardous if not used properly. Many roof cleaners can also damage plants unless the plants are thoroughly soaked before and after use.

For all these reasons, it pays to hire professionals to clean roofs, but it is sometimes difficult to find a pro that uses safe cleaning methods.

 If you are successful in finding a roof-cleaner pro in your area, find out what method of cleaning is used and make sure it is safe for your roof and plants before signing a contract. The roof cleaner should also have liability insurance and worker’s compensation for employees.