Signs You Have a Leaky Chimney

The chimney is a vital part of your fireplace’s ventilation system. It acts like the lungs of your fireplace, inhaling oxygen to fuel the fire and exhaling smoke, carbon monoxide, and other harmful contaminants from your home. For the chimney to work effectively, it must remain watertight.

Cracks in the masonry, flashing seal, or chimney crown can allow water to seep in. Even a small leak can lead to significant structural damage, promote mold growth, and render your heating appliance unsafe to operate. 

Here are five tell-tale warning signs you have a leaky chimney:

1. Water Stains on Walls or Ceilings

Spotting wet stains or peeling wallpaper on the ceiling or walls surrounding your chimney is a clear indicator of moisture intrusion. These stains often indicate that the flashing—the metal sheet where the chimney meets the roof—is failing, allowing rain to leak through the gap. Repairing may be as simple as resealing the seam with a water-resistant caulking or replacing the damaged flashing.

2. Dripping Water Sounds

A leaky chimney often “talks” to you. When you hear the pitter-patter of dripping water inside the flue or your metal damper is rusting, you have a leaky chimney. This is typically due to a cracked chimney crown. For minor cracks, your chimney professional can seal them with Evercrown® for a long-term fix. 

3. Puddles in the Fireplace

Discovering water pooling on the floor of your firebox or hearth can be concerning, and it often indicates a leak. It is usually the result of a damaged or missing chimney cap, which allows water to enter directly. This moisture intrusion can damage chimney liners and rust metal components, such as the damper and the grate. 

4. Bits of Clay and Mortar in the Firebox

Finding small “shales” of clay tiles or chunks of mortar on the floor of the firebox is another sign of a leaky chimney. Spalling is often a byproduct of freeze-thaw cycles and poses a severe structural hazard. It results from the expansion of freezing water that literally pops the face off the bricks or cracks the liner, leaving debris in the firebox. Many chimney professionals use Thermocrete® to repair this damage. This advanced spray-on ceramic coating effectively seals holes and gaps, restoring the chimney liner with a smooth, protective finish.

5. Increase in Rodent or Pest Activity

Water can cause cracks in brickwork and stonework, which serve as an open invitation for pests and rodents, such as spiders, cockroaches, mice, and rats, to enter. If you’ve noticed an increase in activity around your fireplace or inside your home, a leaky chimney could be the issue. After making the necessary masonry repairs, we recommend that chimney and fireplace professionals apply Raintite®. This proprietary formula creates a “breathable” membrane that allows trapped moisture to escape while creating an invisible barrier that repels water, ice, and UV exposure. Raintite® is also safe and effective for use on other masonry surfaces, including stucco, cinder block, and limestone.

Why Timely Repair Is Critical for Chimney Leaks

Prolonging a chimney leak repair is a recipe for a structural failure. In addition to the growth of mold and wood rot in your home’s framing, moisture compromises your chimney. When the chimney liner or masonry is damaged, it can no longer safely contain the extreme heat of the fireplace, significantly increasing the risk of a house fire and exposure to deadly carbon monoxide gas. Fixing leaks as soon as possible saves homeowners thousands of dollars in property damage from a partial or complete chimney collapse.

Let’s Fix Your Leaky Chimney Today!

Approved Industries offers the industry’s best cost-effective and weather-resistant solutions for quickly and permanently repairing chimney leaks. Our advanced protective coatings are used by factory-authorized chimney sweeps, repair technicians, and fireplace installers nationwide. Contact us today for an Approved Industries installer near you.