What Causes Algae To Grow on Roofs? - Showalter Roofing Services
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Algae, Algae Everywhere!

Published by Andrew Schmidt

Algae has been an issue since the develpment of fiberglas shingle.
Algae has been an issue since the development of fiberglass shingle.

Over the past 20 years more and more roofs have been attacked by an algae that has always been around. It was not imported from another country and our climate is pretty much the same as it has always been.  So where did this creature from the black lagoon come from? This black or green staining on roofs has been the source of frustration for many of us homeowners. We have this beautiful home and landscaping and then there is this grungy, grody, ugly roof. It’s like detailing a beautiful car and leaving the wheels covered with grease and road tar.

It all started when shingle manufacturers began using fiberglass as the base mat for making shingles. Because it is much thinner than the rag base material once used, they chose to use limestone as a filler to “beef up” the shingles. Guess what one of algae’s favorite foods is? Yep, this cheap and plentiful filler has now become the food source of the ever present algae spores floating through the air.

However, metal poisons the algae and it does not grow when a metallic substance is introduced to the fiberglass shingle roof. Just like the picture shows, the metal antenna stand has killed the algae below it and the roof is clean. The best way to get rid of algae is to let mother nature and copper strips installed at the top of your roof do the work over time. Some will tell you to use a diluted bleach mixture to clean the roof, but that can harm landscaping and damage the shingles. Don’t even use power washer and shingles in the same sentence. That can make a bad situation worse as your shingles go flying across the neighborhood from the power washer blast!

Tim Carter from AsktheBuilder.com has some good advice for what we have been talking about. Take a look!

How to Cope with Roof Moss

If you need some help doing the things Tim describes, give me a call and we’ll talk about it.


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