Lichen is a composite organism that emerges from algae and fungi. The problem with having lichen on your roof is the fact that lichens have roots or strands that can penetrate into your shingles. Once these lichens are on your roof, we want to eradicate them as soon as possible so their root systems do not get a chance to attach themselves to your roofs shingles. Lichen does not trap as much water to your roofs surface as moss, but it can be acidic, and very damaging to your roof on several levels. Lichen feeds on the limestone that shingle manufacturers put into shingle to make them heavier. The limestone is the lichens food source, so its not going anywhere until it is eradicated by a professional roof cleaner. There is no spray you are going to buy at home depot, or order on-line that is going to kill the lichens on your roof. it is the toughest of all the growths on your roof to eradicate. unfortunately, it is also the most damaging to shingles of all the growths on a asphalt shingle roof. Of all the roofs I inspect for free estimates every year, I find that lichen is present and alive on about 70% of them. Most asphalt shingles have approximately a 30 year life expectancy. If you have lichen growing on your roof, you can cut that in about half. The black algae you find in the dark streaks running down your roof is really an eyesore, though it can cause some damage resulting in numerous years taken off your roofs lifespan. Lichen, is another animal all together. Its root system will eat right through the shingles on your roof, causing possible leaks down the road. in my photo gallery you will find a close up picture of lichen.
My name is Tom Ward, and I own and operate Pro roof cleaning. I bid and do all work for my business. You will not get one person bidding your roof cleaning issue, and then get someone else show up to do the work. At Pro roof cleaning I handle everything. Including answering my phone when a customer calls. So if you are in need of roof cleaning, call me at your convenience. I will be happy to help in any way I can.
Best regards, Tom at Pro roof cleaning