Our Company Blog

Why is My Chimney Leaking?

There are few things more aggravating to a homeowner than having water leaking into their home. Finding the exact source of a leak around a chimney can be particularly frustrating.  The inherent complexity of having a masonry structure pass through a framed roof can turn the proper diagnosis of a leaking chimney into a time-consuming headache.

Annual chimney maintenance is helpful because it alerts you to problems early, before they become catastrophic.

Annual chimney maintenance is helpful because it alerts you to problems early, before they become catastrophic.

To understand the fundamentals of why a masonry chimney will or won’t leak, let’s start at the top of the flue and work down to the roofline.  First, if you don’t have a chimney cap, get one.  An uncovered chimney allows whatever rain and snow are falling to enter right into the fireplace flue.  Over time, that water erodes the mortar joints between the flue tiles and it also damages the chimney as the water is heated into steam during operation of the fireplace.

The chimney crown is the ‘lid’ over your chimney.  It’s useful to think of a chimney as a hollow box built out of cinder blocks or bricks.  To keep water from entering the chimney from above, a crown is poured.  The crown should be concrete that is 4” – 5” thick and contoured to drain moisture.  Lots of chimney crowns in our area were just built with mortar instead of concrete or they lack an expansion joint to allow the top flue tile to expand when the fireplace is in use.  The result is cracks and erosion that allow water to penetrate and cause increasingly larger cracks as the freeze-thaw cycle occurs.

The sides of a masonry chimney are often the least understood culprit when making a leaky chimney diagnosis.  Like all masonry materials, mortar joints will allow water penetration when saturated.  When the mortar joints are cracked or damaged, water easily flows through them and into the space between the cinder block structure and the stone veneer.  It flows downward until it reaches the framing of the roof and into your home.  Even in our dry climate, when a chimney is exposed to excessive rain and snow, it will absorb moisture through the rocks or bricks on the sides. The solution is to locate the weakened joints and cracked rocks and seal or replace them as necessary.

Where the chimney meets the roofline can be the most complicated region of a leaking chimney to diagnose.  Every roof-chimney interface should have an overlapping system that includes both flashing and counter-flashing.  The flashing starts under the roofing materials and runs up alongside the chimney.  The counter-flashing starts out with a ‘cut’ into the side of the chimney and then overlaps the flashing to create a barrier to water intrusion.  Unfortunately, a huge percentage of homes in our community have chimneys that are flashed improperly.  We often see chimneys where the counter-flashing is just placed along the chimney and ‘sealed’ with some type of goop.  WRONG!  Chimneys like these need significant repairs to keep the water out of your home.

To correctly diagnose and fix a leaking chimney, we evaluate the entire chimney as a system: top (cap and crown), middle (stonework or bricks) and bottom (flashing and counter-flashing).  If any of the three sections is leaking, then the chimney has a potential for water to enter the home.  Next month we’ll explain how to find the leaks on a framed chase with a factory-built chimney.

To schedule a fireplace/chimney sweeping and/or inspection – call us today at Mountain Man Fireplace and Chimney, Inc – (303) 679.1601 / 838.3882 or electronically at office@MtnManChimney.com.  Semper Fi!

 

 

 

 

 

Common Chimney Repairs

Getting Started

The one thing you hear the most in the chimney world is to make sure you keep up with your annual maintenance.  This maintenance consists of an inspection and sweep every year.  When researching for a technician, make sure that they are credible.  You can find out a lot about the people working in your neighborhood through word of mouth of family and friends, or also checking internet websites where customers can leave reviews after the service has been completed.

Over time, water will wear down the defenses of your chimney. Common waterproofing repairs include restoring flashing and replacing chimney caps.

Over time, water will wear down the defenses of your chimney. Common waterproofing repairs include restoring flashing and replacing chimney caps.

Anyone you have perform a chimney sweep should be certified by the Chimney Safety Institute of America, (CSIA) a non-profit organization that serves as a great place of information for homeowners.  Having this maintenance done can prevent you from having many other problems arise in the long run, so make sure it is done on time and not just when you think it’s needed.  To schedule your appointment call the professionals at Mountain Man Chimney Fireplace & Chimney.

Biggest Threats

There are many things in a chimney that can malfunction, and can potentially cause big problems even though they seem small in the beginning.  First, water can enter your home and cause mold to form.  This is extremely common in areas that have high precipitation levels.  Water can enter when the flashing on a chimney becomes loose, cracked, or missing.  Sometimes caulk can be used to fix the gaps, but sometimes it will need replacing.

Bricks can become cracked which can also be a place for water to collect.  When this happens, call an experienced sweep that can come repair the unit properly.  They will be able to judge the size of the crack and what needs to be used to fix it.  The chimney crown serves as a roof to the unit, so that must also be repaired if cracked.  Lastly, installing a chimney cap will not only help keep water out, but animals as well.

After a chimney has been repaired, toss a little water on it to make sure that it was done properly and no water is still allowed to enter.  If the surface turns a dark color and absorbs into the chimney, you may still be in danger of water damage.

Taking Care of Business

To take care of this, you should have your chimney waterproofed.  There are special chemicals that form a sealant when applied that will repel the water as it hits the structure.  It is important to have a breathable substance so that vapors are not trapped inside of the chimney.  You always want to make sure that the chimney is cleaned before applying the repellent.

What is the Risk?

When these repairs go unattended they can become much worse.  If a crack becomes larger more water can collect inside of it.  This will lead to more mold, which can spread into the foundation of your home and also the air you and your family breathe.  Also, if you do not have your sweep in a timely fashion you can become susceptible to chimney fires and draft problems that could eventually lead to carbon monoxide poisoning or become a threat to the structural integrity of your home.

We recommend an annual chimney cleaning and inspection, so that we can identify and eliminate problems early on. Waiting is more dangerous and much more expensive. Call today!