This is a good article from the Pittsburgh Gazette about Roof Cleaning
This As if homeowners don’t have enough chores to keep them busy, many shingle manufacturers now recommend periodic cleaning of the roof surface.
You heard right. Many roofs need to be washed to keep them in good shape.
The black streaks seen on many roofs are algae growth which, left unchecked, can shorten the life expectancy of the roof by feeding on the limestone filler used in some newer shingles, according to GAF Materials Corp. of Wayne, N.J., a manufacturer of roofing products since 1886. Proper cleaning can kill the algae.
Frank Shuster of South Park, Pa., noticed the stains on his roof several seasons ago. After replacing the original roof, which Shuster says never had an algae problem, he noticed the unsightly streaking on his new roof about three years after it was installed.
“It was downright ugly,” he says.
He climbed up on the roof with a jug of chlorine bleach to see if it would alleviate the problem. It did, but he says the idea of cleaning the entire roof with bleach did not appeal to him, so he called several roofing contractors about the problem to no avail.
After seeing a flier distributed by Pittsburgh Roof Cleaners, he made arrangements with the company to have his roof cleaned. According to company owner Michael Inks, this type of service is relatively new to Pittsburgh but is quite common in the hot, humid Southern states, where algae can be an extreme problem.
Afflicted roofs have dark streaks that are usually most prominent on the lower section of the roof and taper off as they reach the ridge. The discoloration is caused by the algae’s protective sheath, which turns dark to protect the organism from ultraviolet rays.
Inks first heard about roof cleaning from a man in West Virginia.
“I went to visit the guy and he took me out to a couple of jobs and showed me how it works,” he says.
While algae issues are more serious in the humid South, other parts of the country can have problems too, especially on northern exposures, which receive less sunlight.
Inks’ process, which uses a proprietary solution that includes bleach, can be performed on most roofs in about two hours. Cost starts at $395.
Shuster, whose bill was $525, asked if the cleaning solution would damage his landscaping.
“I was really concerned about overspray and the wind blowing some of these chemicals on my shrubs,” he says. “But they covered the shrubbery and also hosed it down with water during the procedure.
“The vast majority of what they applied went into the rain gutters.”
The need for roof cleaning depends on the severity of environmental contaminants, the frequency of rainfall, the propensity for dirt and dust accumulation, the roof slope and draining characteristics.
There are cleaning recipes available for the do-it-yourselfer, but GAF recommends that the job be left to professionals.
Inks’ company provides a two-year warranty against the return of streaks and offers extended maintenance contracts. It also can clean slate and tile roofs.
If you are thinking of putting on a new roof, you can try to eliminate the need for this chore by requesting that your contractor install algae-resistant shingles.
Susan Banks can be reached a sbanks(at)post-gazette.com. For more stories visit scrippsnews.com
Must credit Pittsburgh Post-Gazette