What Causes Roof Stains
What is the Stain on My Roof?
Whether you’re preparing your home for sale or if you just like to have your house looking its best, home stains on the exterior need to be remedied. When you see something discolored on your roof, siding, or concrete surfaces, you want to remedy it. First, though, you need to find out why the surface is discolored.
Roof Discoloration
Black Stains: Black discoloration is typically caused by one of three things: algae staining, extractive bleeding of the underlying asphalt into the shingle, or soot staining.
- Algae stains appear as black streaks running down the slope of the roof. This black algae is called Gloeocapsa Magma and is pretty tough, though it will not grow around the areas where metallic particles from the chimney run off with the water. Black algae is airborne and the spores will typically start their home on the north side of your home in a shady area. The blackness isn’t itself deleterious to your roof, but it can be an infestation of bacteria and may spread to other parts of your roof. Additionally, it may encourage growth of mold, mildew, lichens, and moss. Algae stains should be removed chemically.
- Extractive bleeding is discoloration of shingles due to a defect in your shingle. The chemistry of the shingle permits the blackness of the underlying asphalt to bleed through to the shingle. It’s purely aesthetic and only needs to be remedied if you’re troubled by the look of it.
- Soot from the chimney can also cause roof staining. It’s usually indicative of a problem with an oil fired heating appliance.
Green Stains: Green staining can be from algae, lichens, or moss.
- Green algae stains are similar to black algae staining. It’s primarily an eye sore and will promote growth of moss and lichens.
- Lichens are usually light green and sort of look like sloppy paint splotches. They don’t retain water as much as moss, so they’re not as problematic as moss. Removal of lichens may cause more damage to your shingles than their simple presence on the shingle.
- Moss can typically be removed easily, either physically or chemically. Moss should be removed, as it can grow a root system which can affect the adherence of your roof shingles. Additionally, moss will retain water and could cause premature aging of your roof and in colder climates, freezing of the moss can damage the shingles.
Reddish-Brown Stains:
- Rust is the primary cause of reddish-brown staining. It stems from rusting chimneys or flashing components.
- This type of staining could also be produced from a malfunctioning oil burner that’s expelling debris through the chimney.
- Sometimes reddish-brown staining stems from red algae.
Other Causes of Home Discoloration
Siding Discoloration
Green or Black: This staining is typically from green or black algae and is fairly easy to eliminate chemically.
Brown, Tan, Gray or White: This type of staining is most likely due to debris from the environment, such as leaves or soil.
Concrete Discoloration
Chalky White Discoloration: When concrete is made, water is added. As it cures, the water will work its way to the surface. If it gets wet, same thing, the water will try to release itself from the concrete, producing a chalky white substance called efflorescence. It has no functional effect on the concrete, only aesthetic. Don’t try to hose it off. Gently scrub the dry concrete surface and wipe with a damp cloth or sponge.
Contact Forte Surfaces for Professional Roof Cleaning Services
Say goodbye to roof stains. Contact Forte Surfaces for expert roof cleaning services that restore your roof’s beauty and protect your Indianapolis home.
