Today we cleaned a beautiful home in Harlan, Indiana. It had some green algae growing in the shaded areas that don’t get much sunlight. In the roof cleaning business we call the green algae stage 3. The black algae starts at the gutter and works its way to the peak. Once the black algae has reached the peak (in this case window) it creates a platform for the green algae to start growing. Stage 3 is like a living sponge and holds moisture. The green alae never allows the shingles to dry out. If you have stage 3 on your roof it needs to be dealt with sooner then later. Eventually the boards underneath will start to rot and could lead to black mold in the attic. The first 2 pictures are before and after from today’s job, and the second 2 pictures are from very serious stage 3 job we did a couple years ago.