How many times have you driven by a house and the first thing that stands out is the roof? Not because of the color or the pattern, but because of the ugly black streaking or discoloration.
What causes this problem? It is either a fungus or black mildew from trees and airborne mechanisms. It also can also be a black soot originating from the fireplace chimney.
How do you get rid of it? Taking a close look at what is near the roof is the first step, is the chimney capped? Is there trees hanging over the roof? I notice this problem when there are many of pine trees near the roof. Living in the northeast near a state park, we have large quantities of pine trees surrounding the homes in the area. Replacing your chimney cap and burning a wood that doesn’t create black soot would help with the problem. Once again pine trees are a culprit, they create soot in the house as well as exiting the chimney. A good hardwood for the fireplace cuts down on the amount of soot being created. I have seen homes that have roofs cleaned every year and continue to have this problem, most of the time they are burning a pine wood in the fireplace.Checkout powerwashing plainsboro NJ for more info.
Step two would be to look at the tree’s hanging over the roof, cut back excess branches or hire a tree service to trim the tree’s. The excess branches create a damp environment well past the time a rain has stopped, dark wet conditions are primers for creating mold.
For step three you would look for defects in the roof. Is there a problem with the shingles causing a bleed thru?
Step four involves cleaning, you want to you use bleach to get rid of this discoloration. I use 1 part bleach to two parts water, it is best to do this project right before it rains to guarantee proper rinsing of roof and also plants around house. It is best to have two people involved with this job on a sunny day, you can have one person cleaning the roof and another continually rinsing roof and flowers. A soft brush gently used on roof will help loosen the dirt giving a good finish. The big box stores are selling products now that help with this process but good old bleach works great, it is inexpensive and nothing kills mildew like it. Some of the harsher products on the market could cause damage to the roof so be careful. A power washer can be used but on the lowest setting to prevent shingle damage. Mercer Bucks Painting and Powerwashing, LLC has cleaned many roofs successfully with just basic products and good old fashion elbow grease.