Coal Tar Sealer vs Asphalt Sealer

Coal Tar Sealer vs Asphalt Sealer: The Direct Answer

Coal tar sealer and asphalt sealer are both pavement sealcoating products, but coal tar sealer resists fuel spills, oils, and UV damage significantly better, while asphalt sealer costs 15–30% less per gallon and is easier to source year-round. Expect to pay $0.12–$0.30 per square foot for coal tar sealing versus $0.10–$0.25 per square foot for asphalt-based sealing, with coal tar lasting 8–12 years and asphalt sealer lasting 4–7 years before reapplication. In short: choose coal tar for gas stations, parking lots, and fuel-exposed surfaces; choose asphalt sealer for residential driveways and budget-sensitive commercial projects.

What Are Coal Tar Sealer and Asphalt Sealer?

Both products are pavement sealcoatings — protective liquid coatings applied to aged asphalt to extend its service life. But they differ fundamentally in their base chemistry.

• Coal tar sealer is refined from coal tar pitch, a byproduct of coke production. It contains high concentrations of polycyclic aromatic hydrocarbons (PAHs), which give it exceptional resistance to petroleum-based solvents.
• Asphalt sealer is refined from petroleum asphalt (bitumen). It is chemically similar to the asphalt pavement underneath, which improves bonding but reduces fuel resistance.

A third category, asphalt emulsion fortified with polymer additives, sits between the two and is often marketed as a "premium asphalt sealer."

Performance Comparison: Coal Tar vs Asphalt Sealer

The single biggest performance differentiator is fuel and oil resistance. Gasoline, diesel, and motor oil dissolve asphalt-based sealers over time, causing premature breakdown. Coal tar's PAH structure resists these solvents, which is why more than 70% of U.S. gas stations and fuel depots use coal tar sealer rather than asphalt sealer.

• Fuel-exposed surfaces: coal tar wins decisively.
• Residential driveways: asphalt sealer performs adequately at lower cost.
• Cold climates: both perform well, but coal tar holds color longer.
• Eco-sensitive areas: asphalt emulsion or bio-based sealers are preferred; several U.S. states and municipalities have restricted coal tar sealant sales due to PAH runoff concerns.

Cost Breakdown: Price per Ton, per Gallon, per Square Foot

Cost is where the comparison becomes practical. Below is a realistic 2024–2025 pricing table for bulk and retail purchasing.

Two applications over 10 years (at 8–12 yr life).

Three applications over 10 years (at 4–7 yr life).

• Coal tar sealer: 250–330 gallons, $4,500–$9,000 installed, lasts 8–12 years.
• Asphalt sealer: 280–400 gallons, $3,800–$7,500 installed, lasts 4–7 years.

Over a 20-year horizon, coal tar often costs less per year of protection despite the higher upfront gallon price — roughly $45–$90/year per 1,000 sq ft vs $70–$140/year for asphalt sealer.

Application, Cure Time, and Seasonal Timing

Both sealers are applied with the same methods — spray, squeegee, or brush — but their cure behavior and seasonal windows differ slightly.

• Do not apply either product within 24 hours of forecast rain.
• New asphalt should cure 6–12 months (or 90 days minimum) before sealing.
• Coal tar requires warmer minimum temperatures to flow properly in squeegee applications.
• Coverage drops roughly 10–15% if the pavement is highly porous or oxidized.

For contractors, buying in bulk (drums or totes, 250–330 gallons) cuts material costs by 30–45% versus 5-gallon pails. A typical 55-gallon drum of coal tar sealer weighs about 440–480 lbs (0.20–0.22 tons), while the same volume of asphalt sealer weighs 420–460 lbs.

Environmental and Regulatory Differences

This is the most contentious part of the coal tar vs asphalt debate. Coal tar sealers contain PAHs at concentrations 100–1,000 times higher than asphalt sealers — typically 50,000–100,000 ppm versus 50–500 ppm in asphalt-based products.

• Austin, TX — banned since 2006
• Washington, D.C. — restricted
• Several counties in Minnesota, Illinois, and Wisconsin — restricted
• Canada — coal tar sealants largely phased out

If your project falls under these jurisdictions, asphalt emulsion or polymer-modified asphalt sealer is the compliant choice. Check local and state rules before specifying coal tar, especially for any surface with stormwater drainage to lakes, rivers, or wetlands.

Coal Tar Sealer vs Asphalt Sealer: FAQ

1. Is coal tar sealer better than asphalt sealer?

Coal tar sealer is better for fuel-exposed surfaces like gas stations and commercial lots because it resists gasoline and oil spills that dissolve asphalt-based products. However, asphalt sealer is better for residential driveways and eco-sensitive areas due to lower PAH content and lower cost.

2. How much does coal tar sealer cost per square foot?

Installed coal tar sealing typically costs $0.12–$0.30 per square foot, including material and labor, while bulk material runs $10–$16 per gallon. A 10,000 sq ft lot costs roughly $4,500–$9,000 for a two-coat application.

3. How long does asphalt sealer last compared to coal tar?

Asphalt sealer lasts 4–7 years before recoating, while coal tar sealer lasts 8–12 years because it resists UV fading and fuel degradation better. Over 20 years, that means 3–5 asphalt recoat cycles versus 2 coal tar cycles.

4. Can you apply coal tar sealer over asphalt sealer?

Yes, as long as the existing sealer is fully cured, clean, and structurally sound — usually after a minimum of 30 days of cure time. Always test a small area first, since some water-based asphalt sealers may not bond well under solvent-based coal tar.

5. Which sealer is more environmentally friendly?

Asphalt sealer is generally considered more environmentally friendly because its PAH content (50–500 ppm) is far lower than coal tar's (50,000–100,000 ppm). For projects near waterways or in regulated jurisdictions, choose asphalt emulsion or a bio-based alternative.

Calculate Your Sealcoating Cost with 6Tar

Whether you are sourcing coal tar sealer, asphalt sealer, or bulk bitumen for a parking lot, gas station, or driveway project, price accuracy makes or breaks your margin. Use the 6Tar cost calculator to compare coal tar and asphalt sealer pricing by the gallon, ton, or square foot — with bulk discounts, coverage rates, and labor estimates built in.

👉 Run your numbers now with the 6Tar cost calculator and get a project-ready quote in under 60 seconds.