How to Repair Your Brick Chimney

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To you, a chimney might seem like a portal from the inside to the outside or like an elongated brick structure. But it’s much more than that; it’s a marvelous machine for generating airflow to the combustion of fuel. What most people know about chimneys is that it is built to get rid of smoke from inside the kitchen or fireplaces.

But when we light a fire in a fireplace, it allows the heat to rise in its column and escape through its outlet, which in turn creates a draft for air to be sucked inside the fireplace, feeding the fire.

The exterior of a chimney is made of bricks while the interior, the flue, the column is generally made up of clay tiles. There are two types of flues, one for the fireplace and the other one for the central heating system in homes.

A chimney also has a crown on its top made out of cement. For your information, if birds roost in your chimney for a long time, they could damage it, and there are certain birds which are called chimney-roosting birds. You cannot fry them or kill them as in certain places; they are legally protected against eviction. Raccoons also tend to live in chimneys.

Just like other types of machines, even chimneys require regular cleaning and maintenance. One should keep getting their chimneys inspected by a certified chimney sweeper who would inspect and clean your fireplace and chimney for masonry chimney repair.


  • There are those that are very easy to repair, such as replacing a few bricks. These are not very expensive and can be done quickly.
  • Some of the ways to repair a brick chimney is by having a contractor come in and demolish the chimney and rebuild it with mortar.
  • Another way to repair a brick chimney is by installing a new clay tile chimney liner, which is a simple solution if your chimney is damaged.
  • The chimney lining is going to make a huge difference in the appearance of your home because of its durability.

You should get your chimney inspected at least once in a year. But this doesn’t imply that you should start doing chimney repairs on your own if you don’t have any prior experience.

In case you are quite a handy person when it comes to repairs, and you are not afraid of heights, then maybe you could try doing it. Just keep one thing in mind that the chimney repair on the exterior can be done by you, but the interior ones should be left for professionals.

There can be a few common issues that occur with all chimneys and are also doable by the homeowner himself, but how would you know how to repair a brick chimney? Here’re a few of the common issues –


  • Problem

Stuff getting inside your chimney flue is definitely not good now, be it rain, leaves, branches, snow, or animals. Generally, there is this cap-type thing hanging over the chimney opening, providing shelter to it from weather, and also has a screen on the inside to keep out critters.

  • Solution

You could go for a new mounting as there are different types of mounting styles, and all are quite straightforward. Some mounting styles can be slid into the flue, which remains in there due to friction. Some others mount to the flue itself.

While there are a few others which mount over the chimney’s crown, the utmost top, which is closed with a chimney sealer, secured with the help of an adhesive. Before mounting any of these, you need to be aware of some things which could create problems in the future.

  • Things that could possibly go wrong

When you are mounting a new cap, make sure you buy one which fits your chimney’s flue or mouth. In case you bring a cap of wrong height, it could mess with the gases that flow through the chimney as much as to revert back smoke into your house (creating a backdraft).

If you are going to install the cap that mounts to the flue, then you must have and use proper hardware and drill bits before getting on with the masonry. Try not to crack the flue, bricks, or the crown, which would create more problems for you; hence, work patiently.

Finally, look out for baby raccoons that tend to nest on the shelf above the damper, right above the fireplace. If in case you don’t see the raccoon babies, then the mother raccoon might chew through the screen to get to the babies. So look harder!


  • Problem

There is a horizontal surface made up of bricks on the very top of a chimney, a surface where water and snow can pool upon. If, in case of water seeps in through the top, it can either degrade the entire masonry or could also destroy the chimney in a way that would require a full chimney rebuild.

To prevent such destruction, the top of a chimney is protected and layered with a special type of mortar called the crown, which provides a weather seal. If it cracks, you might even have to get a chimney crown replacement.

  • Solution

First of all, clean the crumbles and broken pieces, if any. Patch the cracks up and finally, add an entirely new layer of mortar over the cracked crown to get a fresh and un-cracked seal.

  • Things that could possibly go wrong

This is quite a predictable one, though! While you are working on the chimney crown repair, make sure that you apply the right type of mortar, which is flexible enough to allow normal temperature-driven contraction and expansion.

In the end, make sure you give the new crown a little downward slope towards the edges of the chimney for it to shed water away. If you are working on your own, then try to be safe while you’re around the edges of a chimney.


  • Problem

Though the crown on the very top of a chimney’s mouth protects it from the weather, you have to keep the sides of the chimney maintained as well. The bricks which are used on the sides of the chimney’s exterior structure can also penetrate water, inside the column, if they suck!

  • Solution

Well, this one is not that hard at all as you just have to power wash the chimney and then spray chimney sealant on the bricks. There are special sealants in the market made to seal chimneys and protect them against water penetration.

  • Things that could possibly go wrong

You might fall off the roof while working on the edges. So beware and stay safe!


  • Problem

As you know, the exterior of the chimney is exposed to weather and other elements all along its lifetime. Hence, it is quite normal that the mortar will get damaged over time, form cracks, and even wither out in forms of chunks. When such a situation arises, you will definitely have to re-point it as soon as possible.

  • Solution

First of all, choose the correct type of mortar and mix and prepare it according to the damage done, keeping in view the required flexibility for expansion and contraction (or according to the manufacturer’s instructions). Now look for places where the mortar is either damaged or missing. Now fill in the joints and cracks using a mortar bag and trowel.

  • Things that could possibly go wrong

Before doing any repair or applying new mortar, make sure that you remove all the old mortar. You should not squeeze some of the newly made mortar in places where it appears as if some of the old mortar has fallen out. Because filling in places where there is a void can create a joint that has been primed for further failures in the near future.

You could either grind or chisel out the old mortar from its place, clean the gaps using a wire brush, and then add the new mortar.


  • Problem

Now, flashing is what keeps water from seeping in at the point where your chimney enters the roof. While one of its ends is tucked under shingles, the other is mashed into bricks. Water seeps inside the chimney if any damage is done to it or it pulls away.

  • Solution

This, according to the experts, is the most complicated external repair task a house owner would have to undertake. It requires extensive roof and masonry work. Flashing is made out of metal sheets and consists of two parts – the base flashing is tucked under shingles on one end and stays against bricks on the other. The cap flashing secures itself into a groove you’d cut in the mortar and acts as a cover to the top of the base flashing.

First, you would have to cut and bend the base flashing to border the bottom of your chimney, tuck it under the shingles, grind out a groove around your chimney by stepping up the rows of bricks bordering the sides and finally, cut and install the cap flashing.

  • Things that could possibly go wrong

Follow the steps correctly, or else a lot of things could go wrong. It is a typical task to deal with hence, mind the part with mortar, shingles, grooving, and keep a note of the bends and overlaps so that they actually shed water.


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