Ganser Company

Asphalt shingles are among the most popular roofing choices in the United States. Many homeowners tackling exteriors remodeling projects choose this particular roofing material because of its durability, longevity and aesthetics. Like most roofing options, however, it is not impervious to issues.

Over the asphalt shingle roof’s serviceable life, it may show signs of discoloration, which could mean that it is becoming more susceptible to the effects of long-term weather exposure. These roof stains may vary in color, from green and yellow to brown and black. Regardless of what’s seen on the roof surface, the discoloration is something you shouldn’t ignore as it can detract from the curb appeal of your property.

As such, it’s important to learn about the causes of asphalt shingle discoloration to prevent it from occurring in the first place. 

Algae Stains

Black stains along the northern slopes of your roof typically indicate algae. These organisms feed on the limestone filler that is present in the asphalt shingles and may even appear in newly installed roofs. No matter how many times you have your roof professionally inspected or maintained, roofing algae stains cannot be prevented. If it’s not professionally cleaned, it may continue to feed on the limestone until it pairs up with a fungus to form lichen. Not only that, but algae can also trap rainwater in your roof and cause moisture damage.

One way to get rid of algae is to have a qualified roof cleaning service remove the stains using a power washer. Make sure that the pros use low water pressure with a detergent safe to use on your roof. If you are looking to replace your old shingle roof, consider new shingles with copper or zinc granules embedded on the colored stone surface. These specialized particles help prevent algae from growing. Keep in mind, however, that these algae-resistant shingles can only be covered under warranty for less than 10 years, and asphalt shingles usually last between 15 and 30 years. 

Rust Stains

You might think this won’t be possible in an asphalt shingle roof, but many roof repair contractors have noticed red or brown roofing stains on the surfaces of these systems. It’s not because the primary roofing material has metal ingredients in it; the rusting comes from the other components installed like the flashings along the chimneys, vents and other penetrations.  If this is the case, your trusted roofer should be able to inspect it thoroughly. It could be an indication that water is seeping through your roof. 

To stop your roofing system from rusting, you need to determine the source t. One common way to treat rust stains is by using vinegar. Oxalic acid is also a smart solution if you’re dealing with deep stains. While working with these solutions and being on the roof, remember to follow safety measures. For best results, you should hire a roofing professional to fix the issue. 

Hard Water Buildup

White or yellow stains in your roof may suggest hard water buildup from air conditioning equipment or evaporative cooler. Hard water buildup often occurs on the lower areas of your asphalt shingle roof beneath the cooling units and may be visible from afar. If your home has hard water, you may notice mineral deposits or white stains on different surfaces around the interior and exterior of your house. Unlike mold or mildew, it does not pose a health risk, but hard water may negatively affect the appearance of your home and require an upgrade eventually. 

To get rid of the stains, avoid power-washing or scrubbing the surface of your roof on your own as it may worsen the issue. Instead, you may eliminate the traces of damage with a vinegar solution. It dulls the stains without harming the animals or plant beds around your property. If you want to use harsher home remedies, consult your local roofer about solutions that adhere to shingle manufacturer specifications. 

Trees and Plant Debris Stains

Are there green stains or unusual patches on your roof? If there are nearby overhanging tree branches, these stains may be due to seeds, leaves and other debris falling and decaying on the surface. If your asphalt shingle has draining problems, this may result in ponding water, allowing for moss or other related organic growth to thrive. To clean the moss from your roof, you need to prepare a mixture of bleach and water. Let the solution sit on your roof’s surface for 15 to 20 minutes before rinsing it with low-pressure water. You should also consider fixing your roof’s draining issue by getting in touch with a professional roof repair company.

Asphalt Bleed-Through

If your asphalt shingles are nearing the end of their useful service life or if they are of substandard quality, you may notice dark stains or black streaks. Most of the time, this is a tell-tale sign you need to have your roof replaced. When asphalt shingles break down, the black pigment from the asphalt comes up to the surface. This is called “asphalt bleed-through.” Many homeowners tend to confuse asphalt bleed-through with algae stains because of the similarities in discoloration. Get in touch with your local contractor to inspect the roof thoroughly.

Light Spots

Much like asphalt bleed-through, you may also have to consider a roof replacement if your dark- or black-colored asphalt shingles appear lighter and patchy. These may be because of natural aging, weather conditions or poor maintenance. If you notice these light spots, the first thing to do is inspect your asphalt shingle roof. Check for any granules that may have washed off from the roof and accumulated inside the gutters. If your shingles are curled or damaged, you may need to contact a roofing company to have your roof replaced. 

Here at Ganser Company, we make sure that your asphalt shingle roof is in great shape. Talk to our expert roofing professionals to schedule your annual roof inspections and prevent these roof stains from occurring. Our contractors also provide home improvement services for your interior space. Call us today at (608) 222-1243, or fill out our contact form to set an appointment.