Chimney Humidity: Why It Happens & What to Do About It

Chimneys and humidity-caused moisture aren’t good partners. In fact, many components of a chimney system are designed specifically to prevent or reduce internal moisture. You can’t completely keep humidity moisture out of a chimney, but you can reduce its amount and keep it from causing a lot of problems. American Chimney & Fireplace of Louisville, KY, would like to share a little about different types of chimney moisture.

Humidity

Humid weather is no fun for anyone, and it’s no fun for your chimney. During the humid months, moisture can build up inside the chimney structure and lead to several problems.

Bad smells: Moisture mixed with soot and creosote inside a chimney flue can cause some pretty obnoxious odors to drift into your home.

Rusting: Humidity in a chimney can lead to the rusting of metal components, particularly the fireplace damper and possibly sections of a metal chimney cap or chase cover.

Mold: Mold thrives in damp, poorly ventilated spaces, and its spores can become airborne and move throughout the house. Some mold is harmless; some is known to be dangerous to people and animals.

Dealing with a humid chimney

You can’t make the outside air not be humid, but you definitely can keep your chimney clean. Annual chimney sweeping removes buildups of flammable (and smelly) creosote and soot, thereby reducing the odor problem.

Annual chimney inspections will check for rust on metal components and general issues throughout your chimney system so they can be fixed quickly.

Other causes of chimney moisture

While humidity does present some moisture challenges, other causes of chimney moisture are much more serious problems.

A chimney can take on water in a number of ways, including:

• Through cracks in the bricks and open mortar joints
• Through gaps in the chimney flashing that covers the space between the roof and chimney
• Through a damaged (or missing) chimney cap, flue cover or chimney chase top
• Through breaks in the concrete chimney crown

These problems can allow large amounts of water and melting snow into your chimney system, and damage will be inevitable if ignored. Along with effects similar to those caused by humidity, major water intrusion can lead to the following.

Structural damage

Water in the bricks and mortar will gradually deteriorate the chimney structure. The result can be widespread leakage and a chimney that tilts or collapses.

Chimney liner damage

Depending on water’s path into the system, it can affect the chimney liner. A damaged liner will allow dangerous combustion gases, smoke and flames to escape. The result can be carbon monoxide poisoning and a house fire.

Roof and house damage

Roofs, ceilings, walls, flooring and other parts of homes have been partially destroyed because of a leaky chimney. And many of these instances aren’t noticed right at first because the leak is in an area hidden from plain view.

Addressing moisture issues in your chimney

Typical humidity won’t cause the three big problems described above, but it can cause problems. If you believe you’re experiencing any kind of moisture issue with your chimney, call us for a quick inspection and needed repair work.

Reach one of our Kentucky chimney experts by phone or get in touch with our contact form.