What Is a Chip Seal?

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A chip seal is an asphalt maintenance process that extends the life of blacktop, helping to fill in small holes and other minor surface damage. Chip sealing also creates a smooth and vibrant surface, restoring the appearance of asphalt and creating a dark background needed for new parking lines and markings.

A chip seal starts with a spray of hot liquid asphalt, followed by the addition of aggregates. These materials are then pressed and rolled so that they dry and harden, creating a fresh, thin layer of asphalt over the existing pavement.

While not meant to fill in deep potholes or severe cracks, a chip seal is an excellent option for repairing minor damage to an asphalt driveway or roadway. This process also adds a protective barrier over your property’s pavement, extending its expected lifespan. The fresh color of a chip sealant provides a crisp background for new parking stripes and other such lines, as said, ensuring those markings are clearly visible while also reducing glare for drivers.

If you have an asphalt driveway or commercial parking lot, it’s vital that you understand all your options for keeping that pavement maintained and in good repair. To ensure your property’s asphalt is always in good condition, note some information about a chip seal and then discuss this process with an asphalt paving contractor as needed, so your pavement is always safe and looking its best!

Chip Seal vs. Asphalt

First note some vital differences between a chip seal and fresh asphalt, so you know why a chip sealing is a good option for protecting the asphalt in place, as opposed to removing that asphalt or adding new layers over the old:

1. The same materials are used to create both asphalt and a chip sealing, but the application methods are different. Asphalt is produced by heating liquid asphalt and mixing it with aggregates, including gravel, sand, and stones. This mix is then spread onto a road and pressed into place, where it then hardens and dries to form a surface ready for driving.
2. A chip seal also contains liquid asphalt and aggregates; however, the hot liquid asphalt is sprayed or spread over the surface to be sealed. Aggregates are then spread over this hot liquid as quickly as possible, typically within one minute.
3. A pavement or road roller presses the aggregate into the liquid asphalt, often making more than one pass to compact the paving material as much as possible. As the liquid asphalt cools and dries, it then hardens.
4. Loose aggregate is swept away, both immediately after the application of the chip seal and even the next day, to ensure a smooth and safe surface.

Because a chip sealing is applied in layers and not mixed offsite, this process is often much more affordable than adding a new layer of asphalt.

What Is the Purpose of a Chip Seal?

Note the purpose of a chip sealing for your asphalt pavement:

• A chip seal fills in small asphalt cracks, holes, ruts, and other minor damage, providing a safe surface for driving and for pedestrians.
• Chip sealants add a protective barrier between asphalt pavement and harsh sunlight, weather extremes, excessive moisture, heavy vehicle traffic, and other damaging conditions. If your property is located in an area with lots of hot sunlight or changing weather conditions, a chip sealant is often recommended to preserve the overall condition of your property’s asphalt.
• The fresh aggregate in chip sealing provides added skid resistance for vehicle traffic.
• As asphalt ages, it tends to fade in color so that parking lines and other markings become difficult to see. A chip sealant provides a vibrant background for new lines and stripes, making them more visible overall.
• Sealing cracks, chips, and potholes in pavement provides added moisture resistance, reducing the risk of drainage issues on your property.
• Chip sealing corrects what is called raveling, or the loss of aggregate along the surface of asphalt.

What Is a Tar and Chip Driveway?

A tar and chip driveway is installed in the same manner as a chip sealant, starting with liquid asphalt followed by a layer of aggregate. However, a chip seal is applied over a layer of asphalt and acts as a sealant or barrier for that paving material. A tar and chip driveway is installed over a layer of gravel or aggregate or a prepared and leveled surface.

A tar and chip driveway is more durable than a loose gravel driveway but more affordable than asphalt or concrete. The visible aggregate of a tar and chip driveway also provides a very attractive, somewhat rustic appearance, as well as lots of added traction against snow, ice, and rainwater!

The aggregate used for a tar and chip driveway is also available in various colors, shapes, and sizes, allowing you to create a personalized look for your property versus standard concrete or plain asphalt. The materials lasts some 7 to 10 years before it begins to break down and a new layer of chip sealing is required.

What Is a Fog Seal?

Fog sealing is the application of a thin liquid oil or emulsion over asphalt. This application gets its name from how the liquid is sprayed over the pavement, as it resembles a fog or mist when applied. As the fog seal dries, the asphalt appears as if it’s been painted.

A fog seal is an excellent choice for restoring the appearance of asphalt and adding a layer of protection between the pavement and damaging elements. A fog seal also provides a fresh appearance for asphalt, especially useful for when your pavement needs new markings and lines or is extremely faded due to age and everyday wear and tear.

While it offers many advantages for your property’s asphalt, note that a fog seal is not quite as effective as a chip sealant for needed asphalt repairs. A fog seal doesn’t fill in chips, cracks, and potholes as does a chip seal. A fog seal might be considered preventative asphalt maintenance but doesn’t provide the same asphalt repair as a chip seal. Be sure you understand these differences when considering the best way to repair and maintain asphalt on your property.

How Long Does Chip Sealing Last?

A chip seal is very durable and typically lasts some 7 to 10 years, but note that the installation process and everyday wear and tear affect its longevity to a great extent. To ensure your new chip sealant is strong and durable and lasts as long as possible, note some vital information about the installation process and some tips on caring for this material over the years:

• If your pavement has severe potholes, ruts, chips, or cracks, a chip sealing might simply collapse over that structural damage. Ensure that all severe damage and defects are filled in and repaired properly before the application of a chip sealant.
• The weather should be warm during a chip seal application, so that the liquid asphalt doesn’t harden before aggregates are added. Heavy rains and excess moisture also interfere with the consistency of the fresh asphalt sealant, so ensure your chip seal is applied when the weather is dry as well as warm!
• Liquid asphalt does not adhere to chips that are overly dusty or dirty. Never purchase loose gravel or chips, assuming you can use those for a chip seal process and save money, as a professional asphalt paving company will provide clean and dry aggregate for the sealing process.
• Ensure you choose aggregate appropriate for traffic conditions. Heavy vehicle traffic will loosen larger aggregate, so choose something smoother for parking lots and public roads.
• Snowplows are very damaging to larger aggregate, often pulling them out of place. If you use a snow blower for your residential driveway, invest in one with skid plates for protection. Ask a professional snowplow service to adjust their buckets and scrapers, keeping them just above the surface of your asphalt, to reduce the risk of pulling aggregate out of place.
• Inspect your new chip seal on a regular basis, checking for loose or missing aggregate, ruts, sagging areas, and other signs of damage. Have these areas repaired as quickly as possible, to ensure the longest lifespan for your new chip sealant.

Chip Sealing Advantages

While chip sealing is not appropriate for all asphalt driveways and parking lots, it does offer many advantages for property owners:

• A chip seal is often one-fourth to one-fifth the cost of a fresh layer of asphalt.
• Chip sealing improves the appearance of your property’s asphalt instantly, making it look new without the cost of new asphalt.
• Choosing a different color and type of aggregate allows you to change the appearance of a driveway or parking lot.
• Updating the aggregate over your property’s driveway or parking lot also allows you to add more texture for better traction or to encourage water runoff, reducing the risk of vehicle accidents and water damage to your property.
• Chip sealing doesn’t require regular maintenance or additional layers or sealant, as does asphalt and concrete.

There are many other advantages to a chip sealant as well as fog sealing for your property. If you’re curious as to what is a chip sealant and if it’s right for your driveway or parking lot, talk to an asphalt paving contractor about your choices for asphalt maintenance and repair.