5 Factors That Lead to Chimney Leakage

5 Common Areas of Fireplace & Masonry Failure

Water has a dark side. Unseen, it wreaks havoc on a house and sneaks into the tiniest hidden spaces. Over time, the expansion and contraction of water can destroy a stone façade, cause cracks in a sidewalk, or provide the perfect environment for toxic molds to grow behind walls. If there’s a way in, water will find it.

One of the most common entry points is a stone or masonry chimney. The porous material absorbs and holds a lot of water, which seeps into drywall, plaster, wood, and insulation. Finding those hidden entry points and sealing them shut is vital to protect your home from a potentially expensive, unplanned home renovation. Contact Atlanta Chimney Doctor, the expert in chimney repair in Marietta, and schedule a home inspection today.

Missing Chimney Cover

Hands down, missing covers are the most common cause of chimney leaks. A chimney cap prevents water, birds, and other animals from getting inside to nest. Fireplace covers loosen over time and get blown away by high winds from heavy storms. Because the chimney is out of sight, the missing cover often isn’t discovered until some damage has already occurred.

Thankfully, when caught early, a missing cover is an easy, relatively low-cost fix. Add a “Missing Chimney Cover” note to your homeowner inspection checklist every spring or fall, or following major storms.

Cracked Chimney Crown

The crown is located at the very top, or lip, of the chimney. Made of stone, masonry, or concrete, it’s particularly susceptible to cracks from exposure to water and house settling. Large splits or cracks allow water to penetrate the interior of the chimney and seep through masonry. Adding a crown sealant will help prevent small cracks from getting larger. But, in severe cases, the only remedy is complete removal and replacement of the crown.


This occurs most often on retro-fitted chimneys converted from wood-burning to gas fireplaces. The difference in temperature between hot air rising from the fireplace and cold air from outside causes condensation to collect on the brick interior of the flue.

The only way to fix or prevent condensation leaks is a properly-sized insulating liner that covers the gas venting. The air gap between the venting and the liner allows the heated air sufficient space to cool before hitting the cooler air inside the original chimney.

Chimney Flashing

Flashing is traditionally a metal L-bracket fixed around the lower edge of the chimney where it meets the roof. The metal is placed in front of the brick or stone chimney and on top of the shingles to allow water to flow away from the chimney. Water-proof adhesives or sealants are used to prevent water seepage behind or under the flashing. Over time, adhesives deteriorate or the masonry cracks, breaking the seal.

The modern method of chimney flashing is much more effective. A flexible rubber sealant is painted on the base of the chimney where it meets the roof. Once cured, the flashing moves with the roof and chimney as outside temperatures change from season to season.

Crumbling Masonry

Over time, exposure to wind, water, and sun degrade the mortar joints holding a stone or brick fireplace together. The exposed porous surface absorbs and transfers water through the gaps into the walls and attic of the home. A structurally damaged chimney can also collapse, causing expensive property damage, or worse, hurt someone!

Chimney repair and tuckpointing must be done by licensed CSIA-certified technicians. Trust the specialists at Atlanta Chimney Doctor to handle even the toughest fireplace renovation, quickly and professionally.

Serving: Acworth, Atlanta, Alpharetta, Dallas, Kennesaw, Marietta, Roswell, Sandy Springs and more.