What Causes a Leaky Chimney?

We won’t try to sugarcoat it: A chimney leak is a frustrating, sometimes expensive problem to have, which is why, at Home Safe Hearth & Chimney, we spend a lot of time talking to our clients about leak prevention and what we can do to help.

It’s an awful feeling, seeing water leaking into your home and knowing that you have a big problem on your hands. Know that when you see a leak in your chimney, we’re here to help.

Home Safe technicians can certainly make repairs after a leak has occurred, and bring your chimney system back to performing the way it should. But if at all possible, we want to help you avoid that headache to begin with. And the best way to explore prevention starts with the first question most homeowners have after a leak pops up: “How did this happen?”

Some Causes of Chimney Leaks

There are many different potential contributors to a chimney leak, and when we’re troubleshooting, Home Safe technicians take a close look at your entire system to figure out what led to your specific leak. A few of the more common guilty parties:

The Freeze and Thaw Cycle

Masonry materials are strong, but they are susceptible to damage from the elements. Sometimes when a small crack develops — in your chimney crown, for instance — moisture can make its way into that crack, then freeze and expand with cooling temperatures. That expansion puts stress on the masonry, and often creates spalling — basically busting up the masonry from the inside out.

Protecting your masonry from freeze/thaw damage means repairing small cracks and preventing your masonry from absorbing excess moisture. If you’re keeping up with your annual chimney inspections, we’ll find any small cracks and propose repairs before they get worse. For your entire masonry chimney stack, we can recommend a specially formulated waterproofing sealant that stops the absorption of excess moisture, and helps protect your masonry for years to come.

Rust And Corrosion

Certain components in your chimney system — like the chimney cap, chimney chase cover and flashing — are constructed out of metal. And certain types of metals are vulnerable to rust and corrosion. Galvanized metal tends to be the most affordable option for those components, which is why many builders choose it. But galvanized metal isn’t your most durable, long-lasting choice, so we often get calls from clients with rust-streaked, corroded chase covers and an accompanying chimney leak.

Rust damage is also something we’ll look at during a chimney inspection. But if you notice rust streaks running down your chase cover in between inspections, give Home Safe a call. We can replace corroded components with fresh new ones, and talk with you about some more durable options, like stainless steel and copper, which can stand up against weather’s attacks much better and make related leaks much less likely.

Old, Failing Masonry

We love older chimneys. But age can bring its problems — namely, deteriorated mortar joints. Your masonry chimney will be made of brick or stone, joined by water-tight mortar joints. Brick or stone tends to hold up far longer than those joints, and when mortar joints deteriorate, leaks and further damage usually follow.

To repair damaged mortar joints, we use a detailed process called tuck pointing, that involves carefully removing the mortar from the damaged joints, replacing it with new mortar and shaping new joints. Along with tuck pointing repairs, we highly recommend waterproofing too — it’ll help give the brick or stone and mortar a longer overall service life.

Those are just a few of the more common causes of chimney leaks — if you’re noticing water damage and have questions — or want Home Safe technicians to come take a look and find and repair your leak — just give us a call!