When it comes to driveway sealing and protecting parking lots, one of the most common questions property owners ask is: coal tar vs asphalt emulsion sealers, which one is better?
Both products are designed to protect asphalt from water, UV rays, and chemical damage. However, they differ in composition, performance, environmental impact, and long-term value. Understanding the strengths and limitations of each option helps you make the right choice for your pavement.
Let’s break down the differences.
What is Coal Tar Sealer?
Coal tar sealer is a petroleum-based product derived from coal processing. For decades, it has been widely used in commercial and residential pavement maintenance because of its durability and resistance to chemicals.
Coal tar sealers form a tough, protective barrier on top of asphalt surfaces, shielding them from oxidation and fluid penetration.
Advantages of Coal Tar Sealers
- Excellent Chemical Resistance
Coal tar sealers resist gasoline, oil, and other automotive fluids very effectively, making them popular in high-traffic commercial settings.
- Strong UV Protection
They slow oxidation caused by sunlight, helping extend pavement life.
- Long Track Record
Coal tar sealers have been used for decades and are well-known in the industry.
Disadvantages of Coal Tar Sealers
- Environmental Concerns
Coal tar products contain polycyclic aromatic hydrocarbons (PAHs), which have raised environmental and health concerns. Some municipalities restrict or ban their use.
- Strong Odor During Application
The smell can be unpleasant during installation and curing.
- Potential Regulatory Limitations
In certain areas, coal tar sealers are no longer permitted due to environmental regulations.
What is Asphalt Emulsion Sealer?
Asphalt emulsion sealers are water-based products made from asphalt particles suspended in water. Unlike coal tar, they are derived directly from asphalt cement rather than coal byproducts.
An asphalt emulsion forms a flexible protective layer that blends well with the existing pavement surface.
Advantages of Asphalt Emulsion Sealers
- More Environmentally Friendly
Asphalt emulsion sealers contain lower levels of harmful compounds compared to coal tar.
- Improved Flexibility
Because they are asphalt-based, they expand and contract more naturally with the pavement.
- Better Adhesion
Asphalt emulsion bonds well with the existing asphalt surface.
- Reduced Odor
They typically have a milder smell during application.
Disadvantages of Asphalt Emulsion Sealers
- Slightly Less Chemical Resistance
They may not resist gasoline and oil spills as effectively as coal tar sealers without additives.
- May Require More Frequent Application
In heavy-use areas, reapplication intervals may be shorter compared to coal tar.
Major Differences Between Coal Tar and Asphalt Emulsion Sealers
Durability and Longevity
Coal tar sealers are often considered highly durable, particularly in environments exposed to fuel spills. However, modern asphalt emulsion sealers with performance additives can provide comparable durability in many applications.
Both products typically require reapplication every 2–3 years, depending on traffic and climate.
Cost Comparison
When comparing coal tar vs asphalt emulsion, pricing can vary by region and material availability. Coal tar sealers have historically been slightly more affordable, but environmental regulations and supply factors may affect cost.
Overall project pricing also depends on lot size, surface condition, and preparation work.
Chemical Resistance and Performance
Coal tar sealers traditionally offer superior resistance to gasoline and oil. This makes them attractive for high-traffic commercial areas like gas stations.
Asphalt emulsion sealers provide strong protection but may require additives for maximum chemical resistance.
Environmental and Health Impacts
Environmental impact is one of the biggest differences. Coal tar sealers contain higher levels of PAHs, which have led to environmental restrictions in certain regions.
Asphalt emulsion sealers are generally viewed as the more environmentally responsible option.
Application and Drying Time
Both sealers require proper surface preparation and dry weather conditions. Asphalt emulsion typically has a shorter odor duration, while drying times for both products depend on temperature and humidity.
Vehicles should remain off the surface until full curing occurs.
When to Use Coal Tar vs Asphalt Emulsion
Best Applications for Coal Tar Sealers
- High-traffic commercial parking lots
- Areas exposed to frequent fuel or oil spills
- Properties where maximum chemical resistance is a priority
Best Applications for Asphalt Emulsion Sealers
- Residential driveway sealing projects
- Environmentally sensitive areas
- Properties seeking lower odor and reduced environmental impact
- General commercial lots with moderate traffic
Special Circumstances and Considerations
In some cases, choosing between coal tar vs asphalt emulsion sealers involves more than just durability and cost.
- Local Regulations and Bans
Certain cities and states restrict or prohibit the use of coal tar sealers due to environmental concerns. Always verify local guidelines before selecting a product.
- Climate Conditions
Regions with extreme temperature swings may benefit from the flexibility of asphalt emulsion sealers, which expand and contract more naturally with the pavement.
- High-Sensitivity Areas
Properties near schools, waterways, residential neighborhoods, or environmentally regulated zones often prefer asphalt emulsion because of its lower environmental impact.
- Heavy Industrial Use
Facilities exposed to frequent fuel, oil, or chemical spills may prioritize coal tar sealers for their superior resistance—if permitted by local regulations.
- Long-Term Maintenance Plans
If you are planning future resurfacing or pavement rehabilitation, compatibility with existing materials should be evaluated by a professional to ensure long-term performance.
Consulting an experienced paving contractor ensures that special site conditions, usage patterns, and regulatory requirements are properly considered before making a final decision.
Frequently Asked Questions
Choose Smart, Seal Strong
When comparing coal tar vs asphalt emulsion sealers, there is no one-size-fits-all answer. Coal tar offers strong chemical resistance and durability, while asphalt emulsion provides environmental advantages and improved flexibility.
The best choice depends on your property’s traffic level, environmental priorities, and local regulations. Proper application and regular maintenance are just as important as product selection.
If you’re planning driveway sealing or commercial lot maintenance, contact Navarro Paving today for expert guidance and professional sealcoating services tailored to your property’s needs.
