Asphalt Emulsion vs. Coal Tar Sealer: What's the Difference and Why We Use Coal Tar

Understanding Your Sealcoating Options

When it comes to protecting your asphalt investment, sealcoating is non-negotiable. But with different products on the market, how do you know which one delivers the best results? At Advanced Paving and Sealcoating, we're often asked about the differences between asphalt emulsion and coal tar sealers – and why we've chosen coal tar as our preferred solution.

In this comprehensive guide, we'll break down the key differences between these two popular sealcoating products, explain their unique properties, and reveal why coal tar remains our go-to choice for delivering superior protection for our Illinois customers.

The Fundamentals of Sealcoating

Before diving into specifics, let's quickly review why sealcoating matters. Asphalt is continuously exposed to damaging elements like UV rays, water, oil, gasoline, and chemicals. Without protection, these forces accelerate deterioration, leading to cracks, potholes, and eventually, costly repairs or replacement.

A quality sealcoat creates a protective barrier that:

• Shields against UV radiation that dries out and weakens asphalt

• Prevents water penetration that leads to cracks and potholes

• Resists chemical spills that break down asphalt binders

• Enhances appearance with a rich, black finish

• Extends pavement life by years

Now, let's examine the two main contenders in the sealcoating world.

Asphalt Emulsion Sealer: The Basics

Asphalt emulsion sealer is exactly what it sounds like – a water-based emulsion containing asphalt cement particles, clay, polymers, and other additives. This mixture creates a protective coating that bonds with the existing asphalt surface.

Composition and Properties

Asphalt emulsion is essentially made of the same base material as your pavement – asphalt – mixed with water, clay stabilizers, polymers, and sand for texture. Being water-based, it contains fewer volatile organic compounds (VOCs) than coal tar.

Advantages of Asphalt Emulsion

• Environmental considerations: Lower VOC content and fewer potentially harmful compounds

• Application ease: Generally easier to apply with less streaking

• Odor profile: Produces less odor during application

• Regulatory compliance: Faces fewer restrictions in areas where coal tar has been limited

Limitations of Asphalt Emulsion

• Shorter lifespan: Typically lasts 1-2 years compared to coal tar's 3-5 years

• Reduced chemical resistance: Offers significantly less protection against petroleum products like oil and gasoline

• Weather sensitivity: More vulnerable to Illinois's freeze-thaw cycles

• UV protection: Provides less protection against ultraviolet radiation

Coal Tar Sealer: The Gold Standard

Coal tar sealer is derived from coal (a byproduct of steel production) and has been the industry standard for decades. This isn't by accident – it's because of coal tar's exceptional protective qualities.

Composition and Properties

Coal tar is a thick, black liquid produced when coal is carbonized to make coke or gasified to make coal gas. The resulting material creates an extremely durable protective layer when applied to asphalt surfaces.

Advantages of Coal Tar

• Superior durability: Lasts 3-5+ years with proper application

• Exceptional chemical resistance: Highly resistant to oil, gasoline, and other petroleum-based spills

• Weather resilience: Better withstands extreme temperature fluctuations common in Illinois

• Enhanced UV protection: Superior blocking of harmful ultraviolet rays

• Rich appearance: Provides a darker, more uniform finish that many property owners prefer

• Cost-effective long-term: While initially comparable in price to asphalt emulsion, the extended lifespan makes it more economical over time

Limitations of Coal Tar

• Environmental considerations: Contains higher levels of polycyclic aromatic hydrocarbons (PAHs)

• Application challenges: More technical to apply correctly, requiring experienced professionals

• Odor during application: Produces a stronger odor when first applied (though this dissipates)

• Regulatory status: Some jurisdictions have restricted its use (though it remains legal and widely used in Illinois)

Head-to-Head Comparison: Key Differences

Let's compare these two sealcoating options across the factors that matter most to property owners:

1. Durability and Longevity

Coal Tar: Generally lasts 3-5+ years with proper application and maintenance.

Asphalt Emulsion: Typically provides 21-2 years of protection before needing reapplication.

The difference comes down to chemistry. Coal tar creates a harder, more impenetrable surface that better resists breakdown from environmental factors. While advancements in asphalt emulsion technology have improved its performance, it still doesn't match coal tar's longevity in most applications.

2. Chemical and Petroleum Resistance

Coal Tar: Excellent resistance to gas, oil, and other petroleum products; these substances bead up on the surface rather than penetrating and damaging the asphalt beneath.

Asphalt Emulsion: Limited resistance to petroleum products. Because petroleum dissolves asphalt (think about how gas or oil spills can damage your driveway), asphalt-based sealers are more vulnerable to these common contaminants.

For commercial properties like gas stations, auto repair shops, or high-traffic parking areas where oil drips are common, coal tar's superior chemical resistance becomes even more valuable.

3. Application Considerations

Coal Tar:

• Requires more expertise to apply correctly

• Can be diluted with water for specific application needs

• Generally needs 24 hours to cure properly

• Best applied when temperatures are between 50-90°F

Asphalt Emulsion:

• Somewhat easier to apply with less streaking

• Usually faster drying time in ideal conditions

• More temperature-sensitive during application

• May require additional coats for comparable protection

4. Appearance and Finish

Coal Tar:

• Creates a darker, richer black finish

• Maintains its color longer before fading

• Provides a more uniform appearance across the entire surface

Asphalt Emulsion:

• Initial appearance is similar but typically lightens faster

• May show wear patterns more quickly, especially in high-traffic areas

• Often requires more frequent reapplication to maintain aesthetic appeal

Why Advanced Paving and Sealcoating Chooses Coal Tar

After weighing all factors, we've made coal tar our preferred sealcoating solution for several compelling reasons:

1. Superior Value for Our Customers

While both products have comparable upfront costs, coal tar's extended lifespan means our customers enjoy approximately twice the protection for their investment. This translates to fewer applications over the life of your pavement, saving you money and minimizing disruption to your property.

2. Illinois Weather Demands Premium Protection

The Midwest's freeze-thaw cycles, harsh winters, and hot summers create particularly challenging conditions for asphalt. Coal tar's superior weathering capabilities and resistance to the extreme temperature fluctuations we experience make it ideal for our local climate.

3. Real-World Performance History

Our decades of experience have shown us firsthand how coal tar outperforms alternatives in our region. We've tracked the performance of both products across hundreds of properties, and coal tar consistently demonstrates superior longevity and protection.

4. Professional Application Addresses Concerns

When properly applied by our trained professionals, coal tar's environmental impact is minimized while its protective benefits are maximized. Our application protocols ensure the sealer is applied at the optimal thickness, temperature, and condition to ensure maximum effectiveness with minimal environmental impact.

5. Cost-Effectiveness Over Time

While initial costs between the two products are comparable, coal tar's longer lifespan means fewer applications over time. This translates to better protection and lower lifetime costs for maintaining your pavement.

Best Practices for Coal Tar Sealcoating

To maximize the benefits of coal tar sealcoating, we follow these industry best practices:

1. Thorough surface preparation: We clean, repair, and prepare your asphalt surface completely before application.

2. Weather monitoring: We schedule applications during optimal weather conditions to ensure proper curing.

3. Precise mixing ratios: Our team carefully calibrates the exact ratio of coal tar, water, and additives for each specific project.

4. Professional application equipment: We use commercial-grade sprayers and brushes that ensure even coverage and optimal penetration.

5. Adequate curing time: We provide clear guidance on curing times (typically 24 hours) and protect newly sealed surfaces until fully cured.

6. Maintenance recommendations: We advise customers on proper maintenance to extend the life of their sealcoat even further.

The Advanced Paving and Sealcoating Difference

When you choose us for your sealcoating needs, you're not just getting a product – you're getting our expertise, our commitment to quality, and our dedication to extending the life of your pavement investment.

Our professional application techniques ensure that whichever sealcoating product is used, it's applied correctly to maximize its protective qualities and lifespan. We stand behind our work with our satisfaction guarantee.

Ready to protect your asphalt investment with industry-leading coal tar sealcoating? Contact Advanced Paving and Sealcoating today for a free consultation and estimate. Our experts will assess your property and recommend the optimal solution to extend the life of your pavement for years to come.

For more information about protecting your asphalt investment, check out our article on the importance of regular sealcoating.