Tack Coat vs. Prime Coat 

Commercial property managers want to ensure their paved surfaces are high-quality, durable and supportive of their tenants’ needs. Knowing the benefits of tack coat versus prime coat application can help property managers make the best decision for their next pavement installation. 

The paving solution for a particular property depends on the nature of the project. Learn more about prime and tack coats to determine which is best for your needs. 

What Is a Tack Coat? 

A tack coat is a thin coating of asphalt emulsion used in pavement construction. This layer is also known as a bond coat because it binds the existing asphalt or cement to an overlay or forms a bond between layers of hot mix asphalt. A tack coat’s material provides the strength needed to connect the pavement layers, creating a single structure that behaves as a unit. 

This layer of pavement is made of a diluted, slow-setting asphalt emulsion. The tack coat’s ingredients increase its binding properties. The emulsion usually consists of:

  • Liquid asphalt
  • Water 
  • An emulsifying agent 

During pavement construction, construction teams apply tack coat by spraying the asphalt emulsion onto the pavement surface with a distributor truck. Tack coat is typically a light application of the asphalt emulsion. Construction teams can also apply asphalt tack coating in heavier layers before porous asphalt or around patched areas.

What Is the Purpose of Tack Coat? 

A tack coat serves several purposes in the process of pavement construction, including: 

1. Bonding the Layers of Pavement 

Adding a tack coat asphalt layer is vital in creating pavement that acts as a single unit. Asphalt tack coating forms a bond for the next application on the pavement, acting as an adhesive for the road or parking lot. This layer prevents slipping between the layers of the asphalt and reduces separation. 

2. Preventing Water Damage 

Asphalt is durable and long-lasting, which is why the material has been a popular choice for paved surfaces at commercial properties for decades. However, the substrate in asphalt pavement is prone to moisture penetration. Over time, rain and standing water can damage pavement and lead to expensive issues like: 

  • Potholes 
  • Cracking 
  • Pavement foundation failure 

While property managers can use routine patching and resurfacing solutions to repair a water-damaged paved surface, deeper structural issues may indicate that it’s time to replace the pavement. Applying a tack coat during the construction or repair process provides a moisture barrier, reducing the cost of pavement repairs in the future. With a properly applied tack coat, pavement can last longer and repairs are more manageable. 

3. Strengthening the Pavement’s Structural Integrity 

A significant benefit of a tack coat is the increased durability it offers. A tack coat provides strong material bonding that supports the following asphalt layers. This coating acts as a sound foundation for pavement construction.

What Is a Prime Coat? 

An asphalt prime coat is another layer in pavement construction. This layer is applied before the tack coat or other supporting coats and prepares the base layer for additional applications. 

Whether pavement has a prime coat impacts its structural integrity over time. A prime coat primarily protects the substrate of pavement during construction. Since the prepared base layer is granular, a sealer is necessary before adding new layers. The prime coat seals the substrate and shields it during coating installation. 

Manufacturers design prime emulsions for optimal penetration into the base layer. This characteristic helps prime coats enhance the pavement’s strength. Commercial property owners can choose between two primary types of prime coats:

  • Cutback asphalt: Cutback asphalt consists of asphalt cement diluted with cutter stock and is the traditional material for prime coats. However, cutback asphalt releases numerous volatiles into the atmosphere. As a result, many states highly regulate cutback asphalt to reduce emissions. This material also brings other drawbacks like a low flash point. 
  • Emulsified asphalt: Emulsified asphalt is replacing cutback asphalt in many pavement construction applications. This material consists of asphalt, an emulsifying agent and water. Emulsified asphalt is relatively free of pollutants, carries little danger of a fire and can be applied in lower temperatures than cutback asphalt. 

What Is the Purpose of Prime Coat? 

Prime coats are a standard step in pavement construction. Here are some of the effects of properly installing a prime coat: 

1. Creating a Seal Between Multiple Layers of Pavement

The primary purpose of the prime coat is to cover the loose materials of the granular base. As the primary layer of the road, the granular base plays an essential role. This layer supports the pavement’s load, strengthens the entire structure and provides drainage for the pavement. 

Because the granular base is made of gravel and sand, it’s susceptible to shifting. The prime coat enhances stability by filling spaces and binding the base layer to the subsequent coatings.

When the base layer needs a thin layer of hot mix asphalt or a chip seal, a prime coat also creates a durable seal between the base and the other layer. This extra strength prevents the pavement layers from separating. 

2. Increasing Pavement Longevity

A prime coat effectively protects the base layer by penetrating the materials and creating improved pavement durability. Correctly applying a prime coat means pavement will likely go longer without damage. 

The prime coat also increases pavement longevity by blocking other layers from moisture, dust and debris that could cause damage between applications. However, the waterproofing from a prime coat is temporary and requires additional layers for more effective water damage prevention. 

3. Reducing Dust During Construction

Pavement construction can be a dusty process. The traffic of trucks and other tools can stir up a lot of debris. Adding a prime coat asphalt layer reduces dust during construction by sealing the loose components of the granular base. 

Should You Apply a Tack Coat, Prime Coat or Both? 

Commercial property managers are understandably concerned about pavement construction or repair projects. The process a contractor uses for pavement construction dramatically affects the finished product’s durability and the frequency and severity of damage done over time. When considering applying a prime versus tack coat, consider the uses of each type of layer and how they benefit the completed pavement. 

Typically, a prime coat is applied and then a tack coat is sprayed before other layers. This practice is optimal for strengthening the pavement and preventing excessive damage. As prime coats seal the initial pavement layers together, tack coats bond and strengthen the pavement while reducing water damage. This combination of asphalt coats enhances the bond between the base layer and the following coats, which creates a more stable construction. 

However, there are certain situations where a prime coat might not be used. For instance, cool or wet conditions make it more difficult for the prime coat to cure. Paving over an uncured prime coat poses several risks, so using a prime coat in this instance could be harmful rather than beneficial. 

While there are situations where a prime coat isn’t used, the best solution for building long-lasting pavement is to prime, tack and seal the asphalt in multiple layers. Using these asphalt layers ensures the pavement has optimal strength and sturdiness. 

Enjoy Long-Lasting Pavement With ToriTom Services 

With proper application, a prime and tack coat can make your commercial property’s paved surfaces more durable. ToriTom Services offers asphalt paving installation for commercial properties from one of the most knowledgeable and skilled teams in the industry. We can partner with you to find the paving service that suits your property’s needs and guide you through the entire process. 

Whether your tenants are renters or businesses, providing high-quality paved surfaces that meet their needs is beneficial. To learn more about our asphalt installation services, contact us today or call 941-932-2593.