Four Causes of Chimney Crown Cracks


Some might say that your chimney is really the king of your house. After all, it has a crown. 

Okay, nobody says that. But maybe they should. 

Your crown is a fundamental part of your chimney. I’ve mentioned this before, but your chimney is not as strong as you might think. In fact, bricks are highly susceptible to water intrusion. 

The crown of your chimney protects the chimney from potential water damage. 

After years of wear and tear, your chimney’s crown can deteriorate. Cracks will appear. And water will get into your chimney. 

In this post, I’m going to share with you the four most common causes of cracks on your chimney’s crown.

What is the Crown? 

I know I said that your chimney has a crown and to think of it like the king’s crown.

But actually, think of your chimney crown as a rain cap. Whereas your chimney cap covers the flue, the crown actually covers the entire top of the chimney.

The primary purpose of a chimney crown is to protect your chimney from deterioration from time or weather exposure.

When a chimney crown is properly built, you’ll have a slab of concrete or mortar about 2-3 inches thick, extending over the chimney about 2-3 inches.

This design helps direct the water away from your chimney and onto the roof without damaging the bricks and mortar of the chimney structure.

#1 – Natural Wear & Tear

Overtime, the waterproofing sealant on your crown will become less effective. Bricks and mortar are porous materials.

That means they absorb water fairly easily.

If the chimney crown is not retreated with sealant, water can seep into the concrete.

When the water freezes, it expands inside of the brick and mortar. As it expands, it chips away at the brick and mortar.

Then, with extra space from the cracks, more water is able to penetrate, freeze, and create larger cracks.

This creates pathways for moisture to seep into the masonry.

#2 – Improper Construction

We’ve seen a lot of newer homes, built within the last 5-10 years that have cracked chimney crowns.

The main issue from this is that the builder didn’t build the chimney crown properly.

That means that the builder didn’t put a steep enough slope on the crown to help push away the water.

Or the builder didn’t use the right materials.

Both of these options help contribute to quicker deterioration.

#3 – Shifting & Settling

Older chimneys that were built properly with the right materials can still have cracked chimneys.

After several years you could have some cracks, both inside and out of your house.

A general rule of thumb is that it takes about 2 years for your house to settle enough where cracks in the plaster inside are minimal.

It’s safe to assume that the same time frame and rule of thumb apply to the outside of your house, including your chimney’s crown.

After a few years, if you don’t have annual inspections (which you should), you ought to get on top of your roof (bring a step ladder up too) and take a look.

If you’re lucky, you won’t have to worry about any cracks!

#4 – Concrete Shrinkage

Many crowns are made of concrete. That’s what we use to build the crown. 

Some chimney companies use mortar. This is usually okay. But we opt for concrete because it’s stronger and able to withstand weather better. 

But the problem with concrete is that as the moisture content evaporates, it dries and ages. This can cause concrete shrinkage. 

Severe concrete shrinkage is known to cause the crown to crack. 

At Patriot Chimney, we implement a few tactics to help minimize shrinkage with our concrete including: 

  • Limiting water quantity in our mixture
  • Using additives to help decrease shrinkage
  • Using adequate contraction joints and steel detailing. This not only helps to reduce shrinkage but also, just in case, helps with controlling potential cracks in the concrete. 

But we should always be aware that, despite all the steps taken, sometimes no one can fully eliminate the chances of concrete shrinkage.

What Can You Do to Prevent Cracking

Most of the time, there’s nothing you can do to totally prevent cracking. Mother nature is going to do as she pleases.

You can fight it as hard as you can and can help drastically minimize the effects of cracks in your chimney crown.

The best way to ensure your chimney crown is in good condition is to take a look at it. And you can’t do this from the ground.

The safest way to do this is to hire a chimney company to take a look with a level 1 inspection. This will allow the chimney technician to run a camera inside your flue to look for potential water intrusion.

And he or she will be able to look at the crown closely to make sure there are no premature signs of cracking.

Chimney Inspection


You can easily reach out to your local chimney company and have a done-for-you solution in no time!

But navigating through all of the chimney companies in your city can be a chore all on its own. And it makes sense, too. 

Hiring anyone to come into your home to fix something like your chimney shouldn’t be a task you take lightly. So I created a list that you can use to make sure you make the right decision when you need someone to help you in your home. 

Questions to Ask

When you’re hiring a chimney company, you should always ask the following questions before allowing them to come into your home:

  1. Can the company provide references? 
  2. Does the company carry a valid business liability insurance policy? 
  3. Does the company ensure that a certified chimney technician will be on the job? 

If they guarantee all three of those, then you are in a good spot. The technicians don’t necessarily need to be certified by the CSIA, but I do recommend putting in a bit more due diligence before accepting a certification that’s not by the CSIA. 

This is because certifications are a tricky thing, especially in an unlicensed industry like ours. Any company can craft a list of job-related questions and sell them as an exam and certify those who pass. 


I recommend you take a few extra minutes in your research before making your hiring decision to learn more about the certification the company has. Here are a few tips to make sure the certification is reputable: 

  • Is the word “certified” just part of the business name or is it an earned designation? 
  • Is the certifying body a for-profit business or non-profit? 
  • Does the certification need to be maintained and renewed through continuing education as the industry evolves, or is it well enough to be certified through a one-time exam? 
  • Is the certifying body well-established or are they relatively new to the scene? New doesn’t mean “bad” but you should make sure the requirements for certification are more or at least equally stringent as those of more established certifications
  • Is the mission statement of the certifying body focused on educating and protecting homeowners or is it more focused on making it easier to earn a certification? 
  • Does holding the certification require following a code of ethics? 

If you can answer all of these questions, then I think it will be safe to allow the company in your home to work on your chimney. 

Please note that If you are hiring a chimney company to install a cap for you, most of the time, they will need to buy the cap themselves. This is primarily for liability and insurance purposes. 

Besides, it’s probably cheaper for them to buy a cap at the dealer discount than for you to buy one at retail cost.

It doesn’t matter if you are in Roanoke, Lynchburg, Blacksburg, or some other city anywhere in the USA — if you have any questions about the safety of hiring a chimney company, please don’t hesitate to email me at or call me at 540-225-2626. I’m happy to help!

Schedule an Inspection

Patriot Chimney has a few CSIA Certified Chimney Sweeps that you can trust with your home and family.

During your service, you can expect your technician to inspect your chimney with a video camera so we can give a full top-to-bottom, inside out inspection.

We’re licensed, insured, certified, and guarantee you’ll be happy with your service.

1. Schedule

Fill out the form below and someone from our office will give you a call to set up a date and time.


2. Service

Your dedicated technician will arrive at your home on the agreed upon time and get to work!


3. Happiness

You’ll be so thrilled that your family is safe and your energy bills are cheaper that you tell all your friends!

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