What Causes Chimneys to Leak?


Rusting dampers and fireplace doors, discolored walls and ceilings, cracked and crumbling chimney bricks and water pooling at the bottom of Causes of Chimneys Leaks - New Haven - Fairfield CT - Total Chimney Careyour firebox all can signal that your chimney has sprung a leak. When a chimney leak occurs, it can mean costly damage to your home, your chimney and your fireplace. The first step in preventing chimney leaks is understanding where they come from. So what exactly causes chimney leaks?

Failing flashing

Flashing seals the base of your chimney where it meets your roofline. Your flashing should be L-shaped metal trimming that is flush to the base of your chimney. Leaking around the chimney flashing can occur when flashing is improperly installed, cracked or corroded, or when it pulls away from the chimney base. Regularly checking your chimney’s flashing and making sure it is in good repair can save you from a leak that rots your ceiling joists or causes discoloration in your walls and ceilings. If your chimney endures a significant amount of water runoff on your roof, you may want to consider installing a cricket, a metal tent that can divert water away from your chimney’s base.

Misplaced chimney cap

A chimney cap is one of the most crucial components in protecting your chimney from water damage. A proper chimney cap is a tented metal cap affixed to the flue opening with metal caging. The chimney cap prevents water from running down the walls of your chimney, damaging flue tiles and rusting dampers, fireboxes and fireplace doors. If you notice moisture making its way into your fireplace, you should first check to make sure you have a securely installed chimney cap.

Damaged masonry

Most masonry damage is due to water penetration. As porous bricks, chimney crowns and mortar joints absorb water, that water can freeze and expand, causing cracking and crumbling. That minor water damage can lead to major leaks and water penetration that can compromise your chimney’s structure. Address any noticeable water damage before minor water damage before it leads to extensive and costly chimney leaks.

Water penetration

All masonry materials are porous and will absorb water over time. The best way to prevent chimney leaks and water damage in a masonry chimney is with waterproofing. Waterproofing applications block your chimney’s masonry from absorbing moisture. At the same time, the waterproofing material is 100 percent breathable, so any moisture already in the masonry can evaporate, and gases created by your winter fires can still be exhausted.

Especially during the spring, as rainstorms proliferate, it is important to be on the lookout for signs of water damage and leaks around your chimney. If you notice signs of water damage, a misplaced chimney cap, degrading flashing or cracked masonry, contact the chimney experts at Total Chimney Care. We can repair any existing chimney leaks, damaged masonry and help you prevent future water damage.

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