will asphalt sealer adhere to polyurethane sealant



Sealing driveways and pavements is essential to protect them from damage caused by weather elements and everyday wear and tear. Two commonly used sealants are asphalt sealer and polyurethane sealant. However, when it comes to applying a new layer of sealant, it is crucial to understand whether asphalt sealer will adhere to polyurethane sealant. In this article, we will delve into the compatibility of these sealants, discussing their properties, application techniques, and potential outcomes. By the end, you will have a clear understanding of whether it is possible to apply asphalt sealer over polyurethane sealant or not.

1. Understanding Asphalt Sealer and Polyurethane Sealant:

To begin, let's dive into the properties of asphalt sealer and polyurethane sealant. Asphalt sealer is a black, petroleum-based substance commonly used to protect and enhance asphalt surfaces. It acts as a waterproofing agent, protecting the asphalt from moisture, ultraviolet (UV) rays, and chemicals that may cause deterioration.

On the other hand, polyurethane sealant is a synthetic material often used for sealing joints and cracks in various surfaces. It offers excellent flexibility and adhesion, creating durable and long-lasting seals. Polyurethane sealant is renowned for its resistance to UV radiation and temperature extremes, making it a preferred choice for outdoor applications.

2. Applying Asphalt Sealer on Polyurethane Sealant:

Now that we understand the basic properties of both sealants, let's discuss whether asphalt sealer can effectively adhere to polyurethane sealant. While asphalt sealer is designed to bond directly with asphalt surfaces, polyurethane sealant is not compatible with it. Mixing the two sealants can lead to adhesion failure, resulting in flaking, peeling, and an unsightly appearance.

The primary reason for this incompatibility is the different chemical composition of these sealants. Asphalt sealer is petroleum-based, while polyurethane sealant is made of polyurethane polymers. These distinct compositions create a chemical barrier, preventing proper adhesion between the two substances.

3. Preparing the Surface for Sealant Application:

When it comes to applying a new layer of sealant, it is essential to prepare the surface properly. This step becomes even more critical when dealing with incompatible sealants. Here are a few key steps to follow:

a) Clean the surface: Remove any dirt, debris, or loose material from the pavement or driveway. Use a stiff broom or a pressure washer to ensure a clean surface.

b) Repair cracks and joints: Inspect the surface for cracks or joints and repair them using a suitable polyurethane sealant. Make sure to follow the manufacturer's instructions for application and drying time.

c) Remove the existing sealant: If there is a layer of polyurethane sealant already applied, it is crucial to remove it before applying the asphalt sealer. Use a chemical sealant remover or a mechanical scraper to gently strip away the existing sealant.

4. Applying the New Sealant:

Once the surface is prepared, it is time to apply the new asphalt sealer. Here's how to proceed:

a) Select the right asphalt sealer: Choose a high-quality asphalt sealer suitable for your specific project. Different sealers come with varying properties, such as coal tar-based or asphalt-based ones.

b) Follow the manufacturer's instructions: Every sealant product has specific application guidelines that should be closely followed. This includes information on application temperature, drying time, and number of coats required.

c) Apply the asphalt sealer: Use a brush, roller, or sprayer to evenly apply the asphalt sealer on the clean and prepared surface. Ensure complete coverage while avoiding excessive application.

5. Post-application Care:

After applying the asphalt sealer, it is essential to take care of the newly sealed surface for optimal performance and longevity. Here are a few post-application tips:

a) Allow the sealant to dry: Follow the manufacturer's instructions regarding drying time. Avoid foot or vehicle traffic until the sealant has adequately dried and cured.

b) Regular maintenance: To extend the life of the sealant, maintain regular cleaning and sweeping to prevent debris buildup. Additionally, inspect the surface periodically for any signs of wear or damage.


In conclusion, it is not recommended to apply asphalt sealer over polyurethane sealant due to their incompatible chemical compositions. To achieve an effective and long-lasting seal, it is crucial to remove the existing polyurethane sealant and properly clean and prepare the surface before applying asphalt sealer. By following the guidelines mentioned, you can ensure a durable and aesthetically pleasing result for your driveway or pavement. Remember to carefully choose the right sealant products and consistently maintain the sealed surface for prolonged protection and enhanced durability.


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