Understanding a Few Roof Stain Issues

If you have recently moved into a home and have noticed some black stains appearing on your asphalt roof, then you may be extremely worried about the condition of your roof. Stains may be a sign of a serious issue; however, the problem may also be one that you can address. Keep reading to learn about some possible causes of stains and what can be done about them.

Extractive Staining

In some cases, the staining on your roof may be caused by defective shingles. When shingles are created, the paper or fiberglass mats are impregnated with bitumen. This helps to make the shingles strong and waterproof. Sometimes the bitumen does not always soak into the shingle mat properly. When this happens, rain can pull the bitumen out of the mat and the petroleum then runs down the roof. 

The bitumen stains can sometimes leave oily residue in your gutters, so look for this if you notice the stains. Also, extractive stains are long, thick, dark, and generally run down the entire length of the roof. 

Extractive stains cannot be removed from the roof. They are permanent once the show up, and they are also a sign that your shingles may dry out, crack, and deteriorate further. It is best to speak with a contractor like Patriot Roofing about shingle replacement. However, the job often does not need to be completed right away. 

Algae Staining

If you see stains that are a dark shade of green or a lighter black or gray color, then you likely have algae stains on the roof. Algae stains are thinner than extractive stains and are likely to appear in one or several areas of the roof. In other words, you may see more isolated streaks, like in an area where the roof is covered by tree branches.

Algae stains, unlike extractive stains, do indicate that a portion of your roof has become quite wet. The staining is more of a cosmetic problem than a structural one. This means that your shingles do not need to be replaced. You should try to kill and remove the algae though. Trisodium phosphate, oxygen bleach solutions, and copper cleaning agents can all be used to get rid of the algae. 

While algae stains do not mean that you need a new roof, the algae will typically return. When you need a new roof installation, think about having an algae resistant roof installed. This can help to reduce new staining problems. 


Share