Algae spores are transported through the air. When they land on a surface, such as your roof, they cling to it and commerce growth. Oftentimes algae & moss are not evident on your roof until it starts to decay. In order for your roof to last as long as possible, it’s vital that you address the algae growth as soon as you’re able to prevent it from spreading.
What Does it Look Like? Algae on your roof can have a black tint; causing your roof to be stained or streaked. It can also look like green and white splotches. When you have a “stained” look on your shingles, it means that the algae is decaying and has nearly completed its life cycle.
Why Should I Care? Besides the obvious eyesore that algae & moss can create, ignoring the problem can cause algae & moss to spread. The growth of algae & moss on your shingles can shorten the lifespan of your roof because it compromises the integrity of your shingles.
Do I Need a New Roof? Oftentimes the algae can be removed or cleaned and a new roof is not needed. However, waiting too long to address the issue can cause a new roof to become a necessity.
With all of the Technology Today, Aren’t There Shingles Available That Reject the Growth of Algae? Excellent question! If you’re in the market for a new roof, companies like GAF offer shingles with copper embedded into the shingle’s granules which prevent the growth of the algae. GAF backs up this claim with on algae warranty on these type of shingles.
What are Methods that Can Be Used to Clean Algae off My Roof? There are a couple methods that can be utilized to eradicate algae from your roof. They are:
1) Power Washing: While power washing can likely remove the algae off your roof, there’s also a strong chance that the power washing will also damage the granules on your shingles which will drastically lower your roof’s lifespan. This method is NOT recommended especially since it can void some manufacturers’ roof warranties.
2) Soap & water with a scrub brush: Having a professional do this is really the way to go since they are accustomed to walking on roofs (though safety harnesses should still be used.) Algae makes a roof slippery and so does the soap & water mixture. Bleach can also be mixed in with water to create a cleaning solution. However, bleach can damage your landscaping so consider this when opting for this method.
Once My Roof is Algae Free, is There Anything I Can Do to deter its Return? Your best options are zinc or copper strips that are installed under the rows of shingles closest to your roof’s peak. As it rains, the rain transports the metal molecules down the sides of your roof which will kill, though not remove, preexisting algae.