Preventing Algae Growth

Algae on roof shingles

Have a roof that’s not past its prime, but wondering why it looks so dirty? The problem could be blue-green algae. Algae growth on roofs is a problem across the country and in Canada as well. Wooded properties abundant in trees create perhaps the greatest issue, but algae growth can occur on any shaded area of a roof when water evaporation is hampered. Although algae is a bacterium, and lingering moisture may eventually compromise the integrity of the roof, the dominant issue is one of aesthetics as the algae appears as dark streaks or spots.

G. Fedale’s preferred manufacturer of roofing shingles, GAF, has introduced a shingle that includes time-released copper granules to help inhibit algae growth. Copper was once available only in GAF’s designer line, but is now standard in its HDZ Timberline shingles. The time-released nature of GAF’s StainGuard Plus® shingles sets GAF apart from its competitors, says Jason Domanski, general manager of our North Wales office. While the inclusion of copper is now a more common addition to asphalt shingles, its effectiveness is often best during the earlier years of a new roof. By contrast, the time-released process of our GAF shingles ensures consistent protection over time. Moreover, these StainGuard Plus® shingles come with a 25-year warranty against discoloration due to algae. 

For existing roofs, Jason suggests having copper stripping added to the edge of the roof. Although an expensive proposition, it can help prevent algae from occurring. Of course, keeping foliage away from the roof is always important, but not a guarantee against preventing algae growth. Should cleaning be required, G. Fedale works with a couple of companies that will come out and soft-scrub clean the roof. Power-washing is a no-no!