chimney FAQ

Are Chimney Sealants A Good Idea?

Short Answer: Chimney sealants are often a good idea. However, you should keep in mind the pros and cons of using sealants before making any final decisions. While they can help to prevent water damage and increase the lifespan of your chimney, they can be expensive and need to be reapplied periodically.

Lindemann Hero Image

Chimney sealants have become increasingly popular as homeowners look for ways to protect their chimneys from damage, reduce heat loss, and increase the longevity of their chimneys. But are they worth the investment?

The experts at Lindemann have over 50 years of experience with chimney repair and maintenance so we know all about chimney sealants. Let’s explore the advantages and disadvantages of using chimney sealants, helping you make an informed decision based on your individual circumstances and preferences.

What Are Chimney Sealants?

Chimney sealants are protective coatings specifically designed to safeguard the interior and exterior surfaces of your chimney from various environmental factors, such as moisture, temperature changes, and pollutants. These sealants form a durable barrier that enhances the structural integrity and longevity of your chimney. To better understand chimney sealants, let’s delve into their composition, types, and functions.

Composition of chimney sealants

Chimney sealants are typically made from a combination of resins, polymers, and additives that provide enhanced water repellency, breathability, and durability. These materials are carefully selected and formulated to ensure compatibility with common chimney materials, such as brick, stone, and concrete, while also providing the necessary protection against the elements.

Types of chimney sealants

There are two main types of chimney sealants: water-based and solvent-based. Each type has its unique characteristics and advantages.

Water-based sealants:

  • These sealants use water as the primary carrier for the active ingredients.
  • They are generally more environmentally friendly and emit fewer volatile organic compounds (VOCs) during the curing process.
  • Water-based sealants tend to be easier to clean up, making them more user-friendly for DIY applications.
  • While they may take longer to cure, they typically offer good breathability and protection against moisture.

Solvent-based sealants:

  • These sealants utilize a solvent, such as mineral spirits, as the carrier for the active ingredients.
  • They usually provide a stronger bond and can be more resistant to harsh environmental conditions.
  • Solvent-based sealants often have a faster curing time, but may produce higher VOC emissions during the curing process.
  • They can be more challenging to clean up, and may require the use of specialized equipment and chemicals.

Functions of chimney sealants

Chimney sealants perform several essential functions that contribute to the overall performance and longevity of your chimney:

  • Waterproofing: By creating a water-repellent barrier on the surface of your chimney, sealants prevent water infiltration that can lead to masonry damage, mold growth, and efflorescence (a white, powdery substance that forms on brick or stone surfaces due to moisture evaporation).
  • Preventing moisture damage: Besides waterproofing, chimney sealants also help to minimize moisture-related damage by allowing the chimney to “breathe.” This means that water vapor can escape from the chimney while preventing liquid water from entering.
  • Reducing heat loss: Chimney sealants can also help to minimize heat loss through the chimney by forming an insulating barrier. This can contribute to improved energy efficiency in your home and may help reduce your heating bills.
  • Protecting against pollutants and UV damage: Some chimney sealants contain additives that offer protection against pollutants, such as acid rain or exhaust fumes, as well as UV radiation. This added protection can further enhance the durability and lifespan of your chimney.

Advantages Of Chimney Sealants

When it comes to chimney sealants, there are many advantages such as protection from water damage, energy efficiency, and increased lifespan of your chimney. Let’s take a closer look at each of these advantages of using these sealants on your chimney.

Protection from water damage

Chimney sealants create a barrier that prevents water infiltration, thus protecting the masonry and mortar joints from damage caused by moisture. This is particularly important in regions with heavy rainfall or freezing temperatures, where water can penetrate the chimney and cause structural damage.

Enhanced energy efficiency

By reducing heat loss through the chimney, sealants can help lower your energy bills. This is especially beneficial during colder months when you rely on your heating system to keep your home warm and comfortable.

Increased lifespan of the chimney

Preventing moisture damage and reducing heat loss can prolong the life of your chimney. A well-maintained chimney with a sealant applied is less prone to deterioration, reducing the need for costly repairs and maintenance in the long run.

Easy application

Most chimney sealants are DIY-friendly and can be applied with minimal equipment. This means that you can save on labor costs by applying the sealant yourself, as long as you follow the manufacturer’s instructions carefully.

Disadvantages Of Chimney Sealants

Now that you have a good idea of the advantages of using chimney sealants, let’s evaluate some of the disadvantages. Some of these include the cost of applying the sealants, certain compatibility issues, as well as the need for regular reapplication.


While the long-term benefits of chimney sealants can be significant, there is an initial cost involved in purchasing the materials. Additionally, if you choose to hire a professional for the application, labor costs can add to the overall expense.

Possible compatibility issues

It’s crucial to select the right sealant for your chimney. Factors such as the age, material, and condition of your chimney can affect the compatibility and effectiveness of the sealant. In some cases, applying an incompatible sealant can do more harm than good.

Regular reapplication

Chimney sealants are not a one-time solution. They require reapplication every few years, depending on the product’s lifespan and the environmental conditions it is exposed to. This means additional maintenance and expenses over time.

Factors To Consider Before Using Chimney Sealants

Before deciding whether or not to use a chimney sealant, consider the following factors:

  • Climate and weather conditions in your area
  • The age, material, and condition of your chimney
  • Your budget and maintenance preferences

It’s also highly recommended to consult with a professional chimney specialist such as Lindemann who can assess your specific situation and provide expert advice. At Lindemann, we can help you evaluate all of your options and help you to determine the best option for your chimney.


Chimney sealants offer several benefits, such as protection from water damage, enhanced energy efficiency, and increased chimney lifespan. However, there are also potential downsides, such as cost, compatibility issues, and the need for regular reapplication.

Ultimately, the decision to use a chimney sealant depends on your individual circumstances and preferences. Always consult with a professional chimney specialist such as those at Lindemann before making a decision to ensure the best outcome for your home.