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Is Your Chimney Leaking Every Time It Rains?

Expert Chimney Waterproofing in Connecticut – Stop Leaks Fast

Dry Chimneys. Safe Homes. Lasting Protection.

For over 12 years, GMT Home Services has proudly served 3,000+ homes across Connecticut, Massachusetts, and Rhode Island, keeping families safe through professional chimney waterproofing services. Our team is CSIA-certified (Chimney Safety Institute of America) and trained in NFPA standards, ensuring every job is completed with unmatched safety and precision.

Why Chimney Waterproofing Matters

Your masonry chimney is strong against heat but vulnerable to the elements. Rain, snow, and freeze-thaw cycles can slowly wreak havoc on brick chimneys, chimney crowns, mortar joints, and the roof line. Left untreated, water intrusion leads to:

  • Small cracks that expand when temperatures drop
  • Spalling brick surfaces and eroded mortar
  • Structural damage from trapped moisture and freeze-thaw cycles
  • Mold growth, health problems, and costly repairs

The damaging effects of water can compromise the structural integrity of your entire chimney. The Chimney Safety Institute of America recommends applying a chimney water repellent or chimney sealant to prevent these risks and create a watertight seal.

Why Chimney Waterproofing Matters

How We Waterproof Chimneys

We use ChimneySaver, a waterproofing product developed specifically for masonry chimneys. Backed by ASTM tests conducted on durability and effectiveness, ChimneySaver provides long-lasting protection against water penetration while allowing the chimney to “breathe.”

Here’s how our process works:

  1. Inspection & Cleaning – We remove dirt, moss, and debris from the brick surface using safe methods.
  2. Sealing Cracks – Repairing mortar joints, chimney crowns, and small cracks prevents further damage.
  3. Application of Water Repellent – Using a garden sprayer, we apply a unique repellent that is vapor-permeable. It allows water vapor to escape while blocking liquid water.
  4. Second Coat (if needed) – On highly porous bricks or stone, a second coat ensures deeper penetration.
  5. Final Safety Check – We confirm the protective layer is evenly applied across the entire chimney, including the roof line and vulnerable flashing areas.

This process prevents water damage, extends chimney life, and gives you confidence that your chimney is safe for the winter months.

How We Waterproof Chimneys

Seeing Cracks in Your Brick Chimney?

Small cracks in mortar joints or a worn chimney crown may not look serious—but when rain seeps in, freeze-thaw cycles wreak havoc on your masonry chimney. Don’t wait until costly damage appears.

Why Chimney Caps Aren’t Enough

Installing a chimney cap helps block rain and debris—but it can’t stop water from soaking into masonry chimneys. To fully prevent water damage, your chimney also needs:

  • A sealed chimney crown
  • Professional chimney sealer
  • A vapor-permeable waterproofing product designed for masonry

These solutions reduce water penetration, protect against freeze-thaw cycles, and stop safety hazards caused by trapped moisture.

Why Chimney Caps Arent Enough

Protecting Brick Chimneys from Water Damage

Brick chimneys are especially vulnerable because bricks and mortar joints naturally absorb moisture. Without protection, water vapors expand during freeze-thaw cycles, leading to spalling, cracks, and eventual costly damage.

With ChimneySaver water repellents, ASTM tests show that nearly every chimney can be protected—up to 99.9% reduction in water penetration—while still allowing moisture and trapped water vapors to escape.

Protecting Brick Chimneys from Water Damage

Water Leaks Around the Fireplace?

If you notice stains near your roof line, damp odors, or leaks in your fireplace, water penetration is already reducing your chimney’s structural integrity. Without a waterproof chimney sealant, trapped moisture can lead to mold and health problems.

How Much Does Chimney Waterproofing Cost?

The cost of chimney waterproofing depends on:

  • The size and height of your chimney
  • Materials used (brick, stone, or concrete)
  • The amount of cracks or mortar damage
  • Whether a solvent-based or water-based product is needed

On average, one gallon of repellent covers about 100 square feet. While DIY products exist, only a professional chimney waterproofer can ensure a true watertight seal that lasts for years. Investing now prevents costly repairs later.

How Much Does Chimney Waterproofing Cost

DIY vs. Professional Waterproofing

It may be tempting to buy a chimney sealer and try a quick DIY fix, but there are serious risks:

  • Safety Hazards – Working at heights near the roof without proper gear is dangerous.
  • Ineffective Application – Homeowners often miss cracks along the roof line, chimney crowns, or mortar joints.
  • Short-Term Results – Many store-bought sealants aren’t vapor-permeable and can trap moisture inside, causing further damage.

Our certified team applies water repellents tested to withstand freeze-thaw cycles, giving you professional results with warranties for long-lasting protection.

DIY vs. Professional Waterproofing

Worried About Winter Damage?”

When temperatures drop, water trapped in bricks expands—causing cracks, leaks, and dangerous safety hazards. A proper chimney water repellent provides long lasting protection against freeze-thaw cycles and prevents water damage year-round.

Maintaining a Waterproof Chimney

Once your chimney is protected, it’s important to maintain it:

Regular care prevents leaks, costly repairs, and safety hazards—keeping your fireplace, roof, and home safe during harsh winter months.

Maintaining a Waterproof Chimney 1

Why Homeowners Trust GMT Home Services

With 12+ years of experience, CSIA and NFPA credentials, and more than 3,000 homes served, GMT Home Services is one of the best chimney waterproofing companies in Connecticut. Our reputation is built on:

  • CSIA-certified & NFPA-trained technicians
  • Use of industry-leading ChimneySaver waterproofing products
  • Detailed estimates with no hidden fees
  • Expertise in brick chimneys, masonry, and chimney crowns
  • A strong track record of safety, efficiency, and reliability
Why Homeowners Trust GMT Home Services

Protect Your Chimney Today

Don’t wait until moisture, rain, and freeze-thaw cycles cause costly damage to your chimney and home. Get ahead of the problem with a watertight seal and expert care.With our certified expertise and long-lasting protection, your chimney will stay safe, strong, and ready for every season.

FAQs

1. Why is chimney waterproofing important?

Chimney waterproofing prevents water penetration that can damage brick chimneys, mortar joints, and chimney crowns. Without a protective layer, freeze-thaw cycles cause cracks, leading to costly repairs and safety hazards.

2. How does water damage affect a masonry chimney?

Water intrusion can weaken mortar, bricks, and the chimney crown. Over time, trapped moisture expands when temperatures drop, reducing structural integrity and causing further damage to the entire chimney.

3. What’s the difference between a chimney cap and waterproofing?

A chimney cap keeps out direct rain and debris at the roof line, while a waterproofing product—such as a vapor permeable chimney sealer—creates a watertight seal across the brick surface and mortar joints to reduce water penetration.

4. Can all brick chimneys benefit from waterproofing?

Yes. Nearly every chimney, whether brick, stone, or masonry, can benefit from chimney water repellent treatment. It protects against leaks, prevents water damage, and extends the life of materials like concrete and mortar.

5. What type of waterproofing product should be used?

Choose a chimney water repellent product developed specifically for masonry chimneys and tested to ASTM standards. Solvent-based and vapor permeable formulas, like Chimney Saver, trap water vapors while preventing rain from soaking into bricks.

6. How long does chimney waterproofing last?

With proper application of a chimney sealant—often applied with a garden sprayer in one gallon coats plus a second coat for maximum protection—long lasting protection can extend for 10+ years before reapplication is needed.

7. Can waterproofing help prevent health problems?

Yes. By preventing leaks and trapped moisture, waterproofing reduces the risk of mold growth inside the home, protecting indoor air quality and minimizing potential health problems.

8. How much does chimney waterproofing cost?

The cost varies based on the size of the job, type of brick chimney, and extent of existing cracks or water damage. Many certified chimney professionals offer estimates and detailed inspections before sealing the chimney.

✦ Reviews

Honest Feedback from Our Clients

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Colin Paterson profile picture
Colin Paterson
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We had a great experience with Joe and team. Very responsive and thorough - he provided a detailed estimate on all the work needed to be done (we needed a complete rebuild from roofline). The team did a great job and are clearly very good at what they do. They were in and out in two days and their quote was beyond reasonable. Highly recommend.
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Joseph Wendover profile picture
Joseph Wendover
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I had a great experience with GMT Chimney Services. They were extremely responsive and able to come out quickly when I needed help after a bird got stuck in my chimney (thankfully it was fine!). They cleaned my gas fireplace, removed bird nesting and debris from the chimney pipe, and installed a new cover to prevent future issues. The team was professional, neat, and made sure everything was cleaned up before they left. Overall, they were easy to work with and did a thorough job. I would definitely recommend them to anyone needing chimney or fireplace services.
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Natasha Setschinsky profile picture
Natasha Setschinsky
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Alex and Juan were so professional and kind and did the job in a timely manner!!!!
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Dylan Kniska profile picture
Dylan Kniska
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Juan and Alex did a phenomenal job servicing our chimney. Polite, professional and a darn good job! Spent extra hours on the job and made sure everything was working correctly! 5 stars!
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Spencer McCauley profile picture
Spencer McCauley
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Great experience!! Joe and Alex were awesome ... extremely nice, honest, and upfront about everything. The price was very fair, and they worked hard to make sure the job was done right. It’s refreshing to find a company that’s so kind, reliable, and affordable. Highly recommend!!
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Trevor Flanagan profile picture
Trevor Flanagan
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The staff at GMT are professional, well educated, dog friendly, flexible with scheduling and ensure priority to jobs that need it. They use USA made products sourcing from the local community, offering lifetime warranties on most of their products, while also still maintaining very reasonable pricing. Their customers safety and satisfaction are first and foremost and it shows throughout their whole team. Joe came out on a Sunday for my estimate and by Friday of the same week I had my chimney lining replaced, everything detailed cleaned, and a new cap installed.
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Jackie R profile picture
Jackie R
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Joe came to do an initial inspection for my fireplace/chimney and was very informative! I appreciate the time taken to explain the current state of my fireplace and recommendations!
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Jennifer Garcia profile picture
Jennifer Garcia
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After searching for a chimney sweep company that were available to diagnose and repair before the inclement weather arrived, was extremely difficult. But GMT were able to arrive that same night. GMT estimated and fixed my whole situation before the snow touched the ground. I had an emergency situation with a roof replacement I previously had with another company gone bad. CO leaking in and unable to stay in my home. GMT secured the work done the very next day. My family and I were able to come back home after one night out. They were professional and fast in freezing temperatures. Town inspection passed. Service you can count on. Definitely reliable and compassionate. Highly recommend.
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Destinie Marie profile picture
Destinie Marie
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Great experience overall. Joe and Alex were professional, responsive, and easy to work with. Everything was handled smoothly would definitely recommend.
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nicole henderson profile picture
nicole henderson
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Wonderful service. Even showed me how to start a better fire in my wood stove and checked everything to make me more comfortable. Highly recommend!

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