The Problem

Trees and shrubbery provide an organic food source for moss, algae and lichens - and tree shade prevents shingles from drying out. This growth on roofs can hinder drainage and cause leaks and premature roof failure. And contrary to popular belief, moss grows on any side of the roof if conditions are right, not just the north side.

The Remedy

• Remove trees and plants overhanging the roof.
• Carefully clean the roof with surface brooming and controlled low-pressure rinsing. First, a caution: Moss covered roofs are very slippery, especially when wet.
• Alter the ph of rainwater runoff by installing zinc, copper, or galvanized steel strips along or near the ridge line. But remember, this procedure, if improperly done, can be harmful to your roof as well as dangerous for a homeowner and should be performed by a knowledgeable roofing professional.

Other Cautions

• Make sure your roof is in good enough condition to withstand the moss removal.
• Some chemicals used for rinsing may kill surrounding plant life.

A brochure with detailed information on this subject is available from the Western States Roofing Contractors Association. This association can also provide you with a list of roofing contractors in your area with the knowledge necessary to deal with moss control. Visit www.wsrca.com