Unsightly Roof Moss and Algae, is it a big deal?

Unsightly Roof Moss and Algae, is it a big deal?

    Millions of homes in America have unsightly roof moss and algae growing on them. Is it a big deal? Moss and algae flourish in high humidity areas and mostly on the north facing side of the roof and sometimes the west facing side to a lesser extent. Roofs that have shade trees covering a portion of the roof can also have moss growth. These areas dry more slowly and are highly conducive for moss and algae growth.

    Roof moss is a big deal. Moss growth can accelerate roof deterioration as moss has roots that grow under the shingles or other roofing materials. The moss will also keep the areas wet for extended periods of time which also damages the roof. For this reason moss should be removed and treated periodically to prevent premature roof deterioration.

    Algae is the black and green streaks that you see growing on roofs.  This is not as much of a problem as moss, it is certainly unsightly, but is more of a cosmetic issue. Algae does not have the extensive root system that moss has and does not retain as much moisture, however it does retain some extra moisture and will also shorten roof life to some extent. Algae should also be cleaned periodically.

    Controlling Roof moss and algae is not difficult, but usually requires a licensed contractor who is trained to remove the moss and algae properly.  Do not use high pressure power washers as too much pressure can damage shingles. Some prevention measures are as follows:

• Keep leaves, branches and other debris off of the roof as this can retain moisture and promote moss growth. Do not walk on moss as wet moss will be very slippery.
• Use roof moss treatment on roof to prevent moss from returning. Do not use chlorine bleach on the roof.
• Trim overhanging trees away from the roof to allow sunlight to the roof.

    To discourage moss and algae growth, have a roofing contractor install a copper strip at the top of the roof ridge. Copper will wash down the roof and poison the algae and will retard moss growth. The copper will oxidize and blend in with the roof color.

    When replacing your roof, consider purchasing algae resistant shingles, they cost a little more, but are well worth it.

    When I built my home in 1995, I purchased algae resistant shingles. A portion of my roof faces north and after 16 years, I do not have any moss or algae. The other homes in my area have moss and unsightly algae.

    Unsightly roof moss and algae is a big deal and moss should definitely be removed.