• Home
• Articles
• Common Roof Contaminants and How to Remove Them

Common Roof Contaminants and How to Remove Them

Your roof is your first line of defense against the elements, but over time, it can accumulate a variety of contaminants that not only diminish its appearance but also threaten its structural integrity. Moss, algae, lichen, and debris can cause long-term damage if not properly addressed, shortening your roof's lifespan and potentially leading to costly repairs. Different roofing materials, such as asphalt shingles, tiles, and metal roofs, require specific cleaning techniques to effectively remove these contaminants without causing harm.

In this blog post, we’ll break down the most common roof contaminants, discuss the risks they pose, and provide guidance on how to safely and effectively clean different types of roofs. At Thrare Contracting, we specialize in roof cleaning services tailored to protect your roof while restoring its beauty. Whether you have a residential or commercial property, our team can help you maintain a clean, functional, and long-lasting roof.

1. Common Roof Contaminants

Understanding the various contaminants that can affect your roof is the first step in maintaining its longevity and performance. Here are some of the most common contaminants that build up on roofs and the issues they cause.

Moss

Moss thrives in damp, shaded environments, making rooftops a prime location for its growth. Moss typically appears as thick, green clumps that can grow quickly, especially in areas with high humidity or rainfall. While moss might seem harmless at first, it can cause significant problems for your roof.

• Damage: Moss roots itself into roofing materials, often lifting shingles or tiles as it grows. This can create spaces for water to seep into the roof, leading to leaks, rot, and even structural damage.
• Moisture Retention: Moss retains moisture, keeping your roof damp for longer periods, which accelerates the deterioration of roofing materials.
• Aesthetic Impact: In addition to structural concerns, moss growth can make your roof look unsightly, detracting from your property’s curb appeal.

Algae

Algae, particularly the strain known as Gloeocapsa Magma, is another common contaminant found on roofs. It typically appears as black streaks or dark stains and is most common in humid climates. Algae spores are carried by wind and can easily spread across neighborhoods, meaning even new or well-maintained roofs can become affected over time.

• Heat Absorption: Algae stains darken the surface of your roof, causing it to absorb more heat from the sun. This can increase your home’s internal temperature, making your HVAC system work harder and driving up energy costs.
• Aesthetic Issues: Algae stains can make an otherwise clean roof look dirty and aged. These streaks are particularly noticeable on lighter-colored roofs, causing them to appear worn and old.
• Potential for Damage: Algae itself does not cause significant damage to roofing materials, but its presence can trap moisture, leading to long-term problems like moss growth or mold development.

Lichen

Lichen is a combination of algae and fungus that forms a hard, crust-like growth on roofs. It can range in color from white to green or yellow and grows in patches across roof surfaces. Lichen is more difficult to remove than moss or algae due to its strong bond with the roof’s surface.

• Roof Damage: Lichen can penetrate roofing materials, causing granule loss in asphalt shingles, which weakens the shingles’ ability to protect your home. Over time, this can lead to leaks and other structural problems.
• Moisture Retention: Like moss, lichen retains moisture, which can speed up the deterioration of roofing materials and lead to further growth of mold or mildew.
• Challenging to Remove: Lichen is particularly stubborn, requiring more intensive cleaning methods compared to other roof contaminants. If not addressed, it can continue to spread and damage the roof.

Debris (Leaves, Twigs, and Dirt)

In addition to organic growths like moss, algae, and lichen, roofs often accumulate debris such as leaves, twigs, dirt, and even bird nests. Debris buildup is particularly common in areas with lots of trees or during the fall season.

• Clogged Gutters: Leaves and twigs can clog gutters and downspouts, preventing water from properly draining off the roof. This can lead to water pooling on the roof, which increases the risk of leaks and water damage.
• Increased Wear and Tear: Dirt and debris trap moisture, which can accelerate the wear and tear of roofing materials. If left unchecked, this buildup can lead to rotting, mold growth, and even the degradation of the roof structure.
• Fire Hazard: In dry climates, debris buildup can pose a fire risk, especially if dry leaves and twigs are left to accumulate over time.

2. Effective Cleaning Methods for Different Roof Materials

The type of roof you have dictates the best cleaning approach. Using the wrong cleaning method can damage your roof and shorten its lifespan, so it’s essential to tailor your cleaning technique to the roofing material.

Asphalt Shingles

Asphalt shingles are the most common roofing material for residential homes. They are durable, affordable, and available in a variety of colors and styles. However, asphalt shingles can be vulnerable to damage if not cleaned properly.

• Soft Washing for Asphalt Shingles: Soft washing is the safest and most effective method for cleaning asphalt shingles. This technique uses low-pressure water combined with biodegradable cleaning solutions to gently remove contaminants like algae, moss, and dirt without stripping away the protective granules that cover the shingles. Unlike high-pressure washing, which can dislodge shingles and cause leaks, soft washing preserves the integrity of the roof while eliminating harmful growths.
• Chemical Treatments: In addition to soft washing, chemical treatments can be applied to prevent the regrowth of algae and moss. Algaecides and moss inhibitors help maintain a clean roof for longer periods, reducing the need for frequent cleanings.

At Thrare Contracting, we specialize in soft washing techniques to ensure that asphalt shingle roofs are thoroughly cleaned without causing any damage. Our team uses eco-friendly cleaning solutions to safely remove contaminants and restore your roof's appearance.

Tile Roofs

Tile roofs, made from clay, concrete, or slate, are known for their durability and aesthetic appeal. However, these materials can be fragile, and improper cleaning methods can result in cracked or broken tiles.

• Soft Washing for Tile Roofs: As with asphalt shingles, soft washing is the best approach for tile roofs. The low-pressure water combined with cleaning solutions effectively removes moss, algae, and lichen without cracking or dislodging tiles. Pressure washing can be too harsh for tile roofs, as the high pressure can break tiles or loosen them, leading to leaks and water damage.
• Gentle Brushing: In some cases, a soft brush may be used to remove stubborn moss or lichen from the surface of the tiles. Care must be taken not to apply too much pressure, as this can damage the tiles. After brushing, the roof can be rinsed with low-pressure water to wash away any remaining debris.

Regular cleaning of tile roofs not only enhances their aesthetic appeal but also helps prevent moss and lichen from causing long-term damage. At Thrare Contracting, we use safe, proven methods to clean tile roofs, ensuring that your roof remains in top condition.

Metal Roofs

Metal roofs are highly durable and resistant to many common roofing problems, but they are not immune to dirt, algae, and debris buildup. Metal roofs are typically made from materials like aluminum, steel, or copper and can last for decades if properly maintained.

• Low-Pressure Washing for Metal Roofs: While metal roofs are generally more resistant to pressure than other materials, high-pressure washing should still be avoided to prevent damaging the paint or protective coatings. Low-pressure washing combined with mild detergents is effective at removing dirt, algae, and debris from metal roofs.
• Removing Algae and Moss: Algae and moss can still grow on metal roofs, especially in shaded or humid areas. Chemical treatments designed for metal surfaces can help remove these contaminants and prevent their regrowth. It’s important to use products that are safe for metal roofing to avoid corrosion or damage to the roof’s protective coating.

At Thrare Contracting, we offer specialized cleaning services for metal roofs, using techniques that preserve the integrity of the metal while ensuring a thorough clean. Whether it’s a residential or commercial property, we have the tools and expertise to keep your metal roof in pristine condition.

3. Why Professional Roof Cleaning Matters

While some homeowners may be tempted to clean their roofs themselves, roof cleaning is a task best left to professionals. Improper cleaning techniques can cause significant damage to roofing materials, leading to costly repairs or even the need for roof replacement. Hiring a professional roof cleaning service like Thrare Contracting ensures that your roof is cleaned safely and effectively.

Safety Concerns

Roof cleaning involves working at heights, which can be dangerous without the proper equipment and training. Professional cleaners are equipped with safety gear and ladders, allowing them to clean your roof without risking injury.

Preventing Roof Damage

As discussed earlier, different roofing materials require specific cleaning methods. Professionals know which techniques to use for each type of roof, ensuring that contaminants are removed without causing damage. Using high-pressure washing on delicate materials, for example, can cause irreversible harm, while using the wrong cleaning solution on metal roofs can lead to corrosion.

Long-Lasting Results

Professional roof cleaners use specialized equipment and cleaning solutions that provide longer-lasting results compared to DIY methods. At Thrare Contracting, we use eco-friendly cleaning solutions that not only remove contaminants but also help prevent their regrowth, extending the time between cleanings.

Protecting Your Investment

Your roof is a major investment in your property, and regular cleaning is essential to protecting that investment. Professional cleaning services not only enhance the appearance of your roof but also prevent long-term damage, reducing the need for expensive repairs and extending the lifespan of your roof.

Conclusion

Common roof contaminants like moss, algae, lichen, and debris can cause significant damage to your roof if left unchecked. Regular roof cleaning is essential to maintaining your roof’s structural integrity, energy efficiency, and aesthetic appeal. At Thrare Contracting, we specialize in safe, effective roof cleaning methods tailored to your specific roofing material, ensuring that your roof stays clean and functional for years to come.

Whether you have an asphalt shingle roof, a tile roof, or a metal roof, Thrare Contracting has the expertise to remove contaminants without causing damage. To learn more about our roof cleaning services or to schedule an appointment, visit thrarecontracting.com today. Let us help you protect your roof and keep it looking its best!