What is Sealcoating?
Seal coating is a method of protective maintenance to asphalt. The process entails putting a thin, liquid layer on top of the paved surface. It acts like a barrier in protecting the asphalt from potential UV rays damage, rain, snow, and different types of vehicle fluids. This seal coat application does not replace or repair broken areas, although it is applied for protection purposes and will have minor improvement on surface smoothness. This will, because the seal coat is maintained to remain in tack, continue to protect the asphalt underneath it from water, wind, and sun, which is otherwise bound to make the former harden and then crack or even crumble.
Choosing the Right Asphalt Emulsion
- Pavement temperature and air temperature
- Humidity and wind
- Pavement condition
- Compatibility and type of aggregate
Due to environmental limitations, cutbacks are generally prohibited in most locations. Rapid-setting emulsified asphalts (e.g., CRS-1, CRS-2, RS-1, RS-2) are the norm in places like Wisconsin. The emulsions contain:
- Asphalt cement
- Water
- Emulsifying agents
- Additives
Seal Coat Asphalt Process
While each sealing company may have its own specific approach, the general seal coating process typically includes the following steps:
Surface Preparation: The pavement is cleaned thoroughly to remove dirt, dust, debris, and loose stones. A clean surface is necessary for good adhesion.
Minor Repairs: Small cracks and potholes are filled to ensure a smoother and more even application.
Seal Coat Application: Apply the seal coat material, usually by squeegees or sprayers, working in all directions to make sure the surface is evenly covered.
Curing Time: The seal coat must not be disturbed for at least 24 hours after application to give time for the liquid to evaporate and leave a durable protective layer. Avoid driving on the surface while curing, and after curing, sharp turns should be made with caution to avoid stationary wheel movements marking the surface.
Optimal Conditions: Sealing is best done between spring and fall of the year when the temperature is constantly above 55°F during application. In addition, for a period of at least eight hours after application, the possibility of rain should be less than 40% to allow for adequate curing. Sealing the coat outside these conditions may result in an ineffective or improperly set coating.
Two Types of Sealcoat
There are two main types of seal coat, and they differ in the type of binder they use.
Refined Coal Tar Based Seal coating
Refined Coal Tar (RTS) is the thick black liquid that is a byproduct of the distillation of bituminous coal.
This type of binder is composed of thousands of chemicals and has a different molecular structure than asphalt. It is not affected by the destructive elements of weather, the sun’s UV rays, salts, oil, gasoline, fats, and other petrochemicals.
Refined Coal Tar was introduced in the 1950s and has been the industry’s most commonly used sealcoating binder until recently.
Asphalt Emulsion Based Seal coating
The main ingredient of Asphalt Emulsion Based Seal coating (AE) is asphalt cement which is derived from the same oils and materials used in producing asphalt.
AE is known to lack resistance to petrochemicals such as gasoline and oil due to being a petroleum derivative and having a natural tendency to be dissolved with them.
However, it has gained popularity due to its superiority in maintaining surface integrity to asphalt pavement, preventing cracks from occurring. Since its inception, AE’s overall performance has been improved by adding chemicals and specialty rubber polymers.
other type:
Acrylic Seal Coat
While asphalt and coal tar are relatively affordable, acrylic seal coats are the most expensive. This option offers high-quality protection like coal tar and without the environmental dangers. However, due to its high cost, acrylic seal coats are primarily used for small parking lots or sports courts. The price tag is too steep for large-scale projects like roadways.
Oil-Based
Although oil-based seal coats are not advantageous, some people still use them. These coats take the longest to dry and cure, sometimes taking up to seven days. They also produce off-putting smells, and they don’t protect well against UV rays. However, oil is naturally water-repellant, which is the main benefit.
Is Seal Coating Truly Necessary?
While seal coating does not get rid of pre-existing issues such as potholes and cracks, it is also critical to prevent future damage. Property owners and managers who delay seal coating will end up spending thousands of dollars on expensive repairs, for example, resurfacing of asphalt.
By applying seal coating every six years or so, you can reduce long-term maintenance expenses dramatically and improve the performance of your asphalt. A well-maintained seal coat prolongs the life of your pavement and prevents expensive issues from occurring. Its relatively low cost saves you considerable money by preventing expensive repairs in the future.
Seal coat or chip seal
| Feature | Sealcoating | Chip Seal |
|---|---|---|
| Application | Liquid layer | Asphalt layer + stone aggregate |
| Purpose | Preventive surface protection | Seals surface, restores friction |
| Cost | Low to moderate | Moderate |
| Best for | Driveways, parking lots, low-volume roads | Rural roads, weathered pavements |
| Drying Time | 24–48 hours | Faster for traffic resumption |
Health and Safety
Carcinogenic Risk: Many seal coating materials contain cancer-causing agents.
Exposure Routes: Health issues can result from repeated skin contact or inhalation of fumes.
Long-Term Impact: Occasional exposure may not be harmful, but chronic exposure increases the risk of cancer and other serious illnesses.
Coal Tar Emulsions: These are especially hazardous and are the leading source of toxic exposure in seal coating.
Environmental Hazard: Aside from worker health, these materials can also negatively impact the surrounding environment.
Toxic Chemicals: Even non–coal tar sealants may contain harmful substances requiring protective handling.
Final Thoughts
Sealcoating is one of the smartest investments you can make for the long-term performance of your asphalt pavement. Whether it’s a driveway, parking lot, or roadway, routine sealcoating can save you money, prevent damage, and keep your surface looking fresh.
Ready to protect your pavement?
Contact us today for a free consultation or quote!
