Why Is My Roof Discolored?

We often get calls from homeowners asking, “Why is my roof discolored?”  Without looking at the roof itself, there are many causes of discolored roofs or roof stains that we will discuss.  There is a few clues we will consider that will help you determine what causes roof stains including: proximity and stain color.  We will also explore what you can do about unsightly roofing stains.

The Proximity of Your Roof Stain

If you notice roof stains on a portion of your roof, look to see if there is something nearby that may be causing the stain.  The flashing around the chimney may cause stains near your chimney.  Stains under a tree are often due to debris falling or other factors relating to the tree.  When you begin examining your roof, look for clues that have to do with the proximity of the stain and you may find the answer to “why is my roof discolored?”.  If you’re entire roof is stained except one area, this may be a clue too.

The Color of Your Roof Stain

Another clue to roof discoloration is the actual color of the stain.  If you notice a red or reddish brown stain you most likely are dealing with rust.  Again look at the proximity of the stain and see if there are metal flashings, a metal chimney, metal antenna mounts or anything else that might be causing rust.  You would be amazed how big an area of red discoloration can occur from just a small rusting object. 

Black stains can also occur.  If the black stains are under a nearby tree, it is probably from debris or possibly algae growth.  Algae growth is also common on shaded areas of your house.  Black stains also are caused by organic debris, dirt, soot and sooty mold.  If you notice black streaks or a black pattern running down the roof, you most likely have bleed through or extractive bleeding.  This is caused by a loss of black pigment in the asphalt mix that is bleeding through to the top of the roof surface.

White Stains are usually caused by paint that has washed down from dormers or gables.  Sometimes salt stains will also occur from copper or aluminum flashings.

Green stains are almost always algae, fungus or moss.

Why Is My Roof Discolored and What Can I do?

There are many reasons for a discolored roof.  It is important to keep trees and other debris away from the roof surface.  Sometimes you can prevent some discoloration. Most of the time roof discoloration has little to do with the longevity of your roof.  Most of the time the removal process does more to harm your roof than the discoloration itself.  You should never use a pressure washer to wash your roof.  Harsh chemicals and bleach might also damage your roofing materials.  It is best to check with your roofing material manufacturer for the best way to clean your roof.  Sometimes a roof stain is caused by a oil heater that is not working properly.  If is important if you see rust stains that you make sure your flashing isn’t leaking or there isn’t a damaged piece of metal that is causing a problem or is about to.  Choosing algae resistant roofing material and a high quality roofing material can also prevent some discoloration.  If you have questions similar to “Why is my roof discolored?” or if you would like to discuss your roof, please call AnyWeather Roofing and we would be happy to help you.