Why Does My Chimney Leak When it Rains?

If you notice that your chimney leaks during heavy rain, you need to act quickly. Finding the exact source of the leak can prove to be a difficult task because of how complicated a home’s chimney system is. The moisture caused by a leaky chimney can lead to the formation of mold, rot wood, or even damage your home’s finishes (plaster, wallpaper, or paint).

If not immediately addressed, the damage caused by chimney leaks can cause the collapse of the entire chimney structure, or even part of your home. If you notice a moisture spot on your ceiling, usually where the chimney intersects with the wall, you very well may be facing a chimney leak.

There are many reasons why a chimney leaks following heavy rain or snow. In some cases, a leaky chimney may become a chronic problem for a homeowner. Whatever the case may be, it’s important to properly diagnose the leak’s origin so that the source of the problem can be corrected.  

If you’re a homeowner with a leaky chimney in Central Indianapolis, Chimney & Masonry Outfitters can help you get your structure back in good shape. We specialize in diagnosing and fixing chimney leaks. And because customer care and satisfaction are always top priorities for our team, we guarantee our work.

Common Causes of Chimney Leaks

Chimney leaks can be difficult to pinpoint. Leaks can literally come from anywhere on a chimney, which is why locating the source can be tedious, especially for the untrained eye of the average homeowner.

Although chimneys are just a small part of your home’s overall architecture, they play an extremely important role in ensuring the health and safety of your living space. If you suspect you have a leak, you may notice water seeping through a wall or coming through the fireplace. A damaged chimney can be costly to repair if the problem is not found and addressed early on. 

There are at least three areas of the chimney where chimney leaks can occur:

  •       Mortar that is cracked or loose
  •       Cracked chimney flashing
  •       Damaged roof shingles

Once a leak has been properly identified, repairs can begin. Depending on the source, repair costs for a leaky chimney can range from a few hundred dollars to $1000+ if the problem is with the brick or mortar. Below are some of the common causes of chimney leaks: 

Chimney Mud Cap 

The mud cap is the mortared area surrounding the top of the chimney. If this area becomes cracked or loose, rainwater can get into the fireplace. Usually water is present in the hearth, but sometimes rainwater can change course and end up in other areas of the home.  

To fix the issue, the mortar cap must be replaced and a flue cap should be inserted. Homeowners can also choose to cover the entire chimney top with a full-sized metal chimney cap.

Chimney Mortar Joints 

Over time, mortar joints can deteriorate, leaving holes for water to enter through. In cases where large sections of the mortar in the joints is completely missing, water can come through during blowing rains. Water that enters a hole in the mortar joint can travel to holes in the bricks, zigzag past the flashing, and end up in the ceiling or land up on the slab. 

This area of the chimney can be repaired by repointing mortar joints with new mortar.

Chimney Flashing

When leaks occur around the chimney flashing, identifying the source can be difficult. Even one small hole in a corner of the flashing can leak a large amount of water during a hard rain. 

An expert sheet metal contractor or roofing contractor should he hired to professionally repair the flashing. 

Roof Shingles 

Roof shingles can also be the source of a leaky chimney. If you believe that a leak is present in this area, it’s best to have a professional examine the area and repair the shingles. Missing, worn or damaged shingles should be replaced as necessary. 

Is Your Chimney Leaking?

Oftentimes homeowners assume that a leaky chimney will always show up as water dripping in the fireplace or flue. However, a home’s chimney system is extremely intricate, and a chimney leak may not be identified until after significant damage has already occurred. 

The following may be signs that you have a chimney leak: 

  •       Moisture collecting around the base of the chimney
  •       Musty odor coming from the fireplace, especially after it rains
  •       Dripping sounds coming from the chimney  
  •       Water puddle forming at the bottom of your fireplace
  •       Water stains on your wall around your fireplace

How to Prevent Chimney Leaks

One of the most important reasons to schedule your annual chimney inspection is to get a professional assessment of the health of your chimney system. The experts at Chimney & Masonry Outfitters know how to identify and repair chimney leaks, preventing more costly damage on down the line. 

We can also answer your questions about waterproofing your chimney, helping you to protect your investment for years to come. Enjoy your home without worrying about chimney leaks– contact our chimney technicians today for an inspection.