Roofs with mold, algae or dirt can be cleaned without voiding the manufacturer’s warranty.

I wrote to the manufacturer of CertainTeed shingles and to the Asphalt Roofing Manufacturers Association in Washington, DC. Asked simply, “How can algae and mold be removed from asphalt shingles without voiding the manufacturer’s warranty?”

Karl D. Loeffler, Sales Support Representative for CertainTeed Corporation emailed back with:

“We recommend a solution of 1 part bleach, 3 parts water and ½ teaspoon of trisodium phosphate or TSP. Just apply the solution and then rinse off after 7 – 10 minutes with a garden hose. Avoid any scrubbing or brushing as this can damage the shingle.”

Shawn Richardson, Industry Affairs Coordinator for the Asphalt Roofing Manufacturers’ Association provide a link to a tech bulletin on discoloration of roofs which explains the origin and effects of algae and moss growing on roofing and suggest the use of cleaning techniques. They do not recommend high pressure water systems.


He also suggested an article:


Professionals are recommended along with personal protective equipment. Cautions are given that bleach not handled and used carefully can damage plants.

I have used the same roof cleaning service twice a year for the past eight years. My roof is now fifteen years old and still described as “in pretty good shape.”

Jon Haas, ARB

My Profile Community Contacts Help Privacy Advertising About the Website
2220 Loch Rane Boulevard |  Orange Park, FL 32073 |  (904) 395-2391
Copyright © 2019 Neighborhood Publications, Inc. - Policies - Sitemap