The Absolute Guide To Brick Chimney Waterproofing – 5 Steps

Chimneys are often overlooked when it comes to home maintenance. In this article, we will discover the proper way of chimney waterproofing.

While people focus on aspects like the front door, garage, and lawn, the fireplace and chimney are equally important components of a home.

Interestingly, the fireplace ranks high among sought-after features for homebuyers, emphasizing the importance of chimneys. 

Understanding their importance is essential for maintaining a safe and functional living space.

Potential Issues You Might Encounter with Brick Chimneys

1. Water Damage

Brick chimneys are susceptible to water infiltration, which can lead to deterioration of the mortar joints, brick spalling, and even structural damage over time.

2. Creosote Buildup

Creosote, a byproduct of burning wood, can accumulate inside the chimney over time. If not regularly cleaned, creosote buildup can pose a fire hazard by increasing the risk of chimney fires.

3. Cracks and Deterioration

Due to exposure to weather elements and thermal expansion and contraction, brick chimneys may develop cracks and signs of deterioration over time. These chimney issues should be addressed promptly to prevent further damage.

The Absolute Guide To Brick Chimney Waterproofing

Step 1: Assess the Current Condition

Before starting the chimney waterproofing process, thoroughly inspect your chimney for any existing damage such as cracks, deteriorated mortar joints, or spalling bricks. Address any necessary repairs before proceeding with waterproofing to ensure a solid foundation for the waterproofing materials.

Step 2: Choose the Right Waterproofing Product

Select a high-quality chimney waterproofing product specifically designed for masonry surfaces. Common options include siloxane or silane-based water repellents, which penetrate the brick surface to create a protective barrier against moisture while allowing the chimney to breathe.

Step 3: Prepare the Chimney Surface

Clean the surface of the brick chimney to remove dirt, debris, and any existing coatings using a stiff brush or power washer. 

Allow the chimney to dry completely before applying the waterproofing product. Ensure there is no moisture present, as it can interfere with the effectiveness of the waterproofing treatment.

Step 4: Apply the Waterproofing Solution

Follow the manufacturer’s instructions carefully for the application of the waterproofing product. Using a sprayer, roller, or brush, evenly apply the solution to the entire surface of the chimney, working from the bottom up. 

Pay special attention to mortar joints and any areas prone to water infiltration. Apply multiple coats if necessary, allowing sufficient drying time between coats.

Step 5: Monitor and Maintain

Regularly inspect your chimney for signs of water damage or deterioration, especially after heavy rainfall or severe weather conditions. 

Reapply the waterproofing treatment as needed to ensure continued protection against moisture intrusion. Additionally, consider installing a chimney cap or crown to further enhance protection against water penetration.


Properly waterproofing your brick chimney is essential for maintaining its structural integrity and preventing water damage. 

By following these steps and using high-quality waterproofing products, you can effectively protect your chimney from moisture infiltration and prolong its lifespan.

Ready to waterproof your brick chimney and protect it from moisture damage? 

Contact us today for expert assistance and ensure the longevity and functionality of your chimney.