Chimney Repointing – Reasons, Procedure & Frequency

Here is all about chimney repointing; the causes, steps to carry out, and how often the procedure should be done.

A chimney performs a very important task (majorly that of venting out the products of combustion from homes).

With such an important function comes the need for maintenance. One of the main tasks of maintenance is also known as repointing.

If this is the first time you’ve heard of this term, you only need to read on to find out more. You’ll also find out how repointing is done.

What Does Chimney Repointing Mean?

Before we get into the details on chimney repointing, it will be necessary to explain what this term actually means.

Chimney repointing simply means the process of maintenance where the external portions of mortar joints are renewed. Renewal or maintenance of chimneys becomes necessary over time as the effects of the elements take their toll.

So, how do you know when your chimney requires some repointing? It’s easy! This takes us to our next point.

When Does A Chimney Need Repointing?

This is an important question that requires the right answers. It is necessary to be able to identify common signs that show the need for urgent action.

Several signs include a rusted firebox or damper, shaling flue tiles, damaged wallpaper, damaged mortar joints, spalling bricks, and cracked chimney crown.

  • Rusted Firebox or Damper

One of the most common signs that reveal the need for repointing is a rusted firebox or damper (or both).

Moisture is one of the easiest ways to detect this. Too much moisture will result in rust on the damper or firebox components of the chimney.

Such rusting will have negative resulting impacts such as cracks on flue tiles which in turn are likely to result in house fires.

On noticing these signs, the need for repointing should be paramount.

  • Shaling Flue Tiles

Another sign that points to the need for chimney repointing are when you notice thin slices of chimney tiles piling up at the bottom of the chimney. This problem is due to the damage caused to the liner. The ideal condition should be a perfect flue lining.

Anything less than a perfect flue lining is likely to lead to house fires. Upon noticing anything short of this, you’ll need to carry out some repointing of your chimney.

  • Damaged Wallpaper

One of the most visible signs that point to the need for chimney maintenance or repointing is damaged wallpaper. Damaged wallpaper in areas close to the chimney could be due to excess moisture from the chimney.

This shouldn’t be and must be fixed as early as possible.

  • Damaged Mortar Joints

Damaged mortar joints point to the need for chimney repointing. This is common in chimney masonry which results in failing joints.

This in turn exposes the bricks to increased moisture, thus causing even more risks of further damage to the chimneys.

The best way to take care of the problem is to have it repointed.

  • Spalling Bricks

Spalling simply refers to the gradual crumbling of a chimney through the action of water. This causes peeling or flaking off of the surface.

Signs of spalling bricks are easily noticeable as bits of masonry falling from the chimney.

This is a condition that points to the need for chimney repointing.

  • Cracked Chimney Crown

The chimney crown is usually meant to act as the first line of defense against the elements.

With a failing chimney, such may not be the case as the crown may be breached or damaged. When this is cracked, it degenerates fast as the water gets into such cracks which freeze, thus making it even worse.

As moisture seeps into the cracks it gets between the liner and the chimney. This then leads to both spalling and shaling.

How Frequent Should A Chimney Be Repointed?

To maintain a functional chimney, necessary maintenance will need to be carried out at set intervals. The frequency of such maintenance is what matters most. Chimney repointing needs to be done every 30 to 50 years. This is great because maintenance isn’t as frequent.

During this time, yearly inspections of the chimney will be needed to determine if there’s an urgent problem that needs to be fixed.

Repointing will be needed when there are separations between the bricks and mortar. Probing or scratching the mortar using an object such as a screwdriver will be necessary.

This action helps to determine if the mortar is loose or not. Bad mortar gives way leaving a gouge that needs to be filled up. Only then should the need to have it repointed arise.

How to Repoint A Chimney

Having explained repointing as the need to replace degraded mortar, It is necessary to ensure that it is done properly.

If you’ve wondered how to get the job done, this section will provide you with all the answers. The steps involved include the following;

  • Remove the Old Mortar

The mortar used on chimneys gets weakened over time and will need to be replaced. Therefore, old mortar must first be removed before a new one is replaced. You must carry this task systematically.

In other words, old mortar removal should be done in sections.

The reason for doing it one section at a time is to avoid weakening the structure’s integrity. Begin the old mortar removal process by covering areas 3 to 5 feet wide at a time. Both horizontal and vertical joints should be targeted.

Handy tools to perform this important task range from an angle grinder, joint raker, handheld grout saw, or cold chisel among others. About half an inch of mortar will need to be removed.

You must also be careful not to cut into the bricks.

What more? A lot of dust from debris will be common when removing old mortar. As such, a respirator is very important protective equipment. Hose, whisk broom, or wire brush should be used to remove the dust.

  • Soak the Wall

Having removed the old mortar, the chimney wall will need to be soaked wet.

Get a hose and soak the walls, allowing it to sit overnight. The reason for this is simple. When allowed to soak, the bricks and remaining old mortar won’t absorb or soak up the water from the new mortar.

It’s also important to lightly spray additional water on the bricks before applying new mortar.

  • Mixing the New Mortar

Preparing the new mortar should be your next step.

However while doing so, you’ll need to be sure you’re using the right mortar replacement. Older buildings (those more than 50 years old) mostly need different mortar mixes than newer ones.

While standard Portland cement mortar will mostly serve the purpose for buildings below 50 years old, a different approach or mix will be needed for older ones. Older structures are most likely to consist of brickwork made of lime and sand.

Thus, the same material should be used as a replacement when mixing the new mortar. If you aren’t sure about what you’re dealing with, it will be helpful to seek the help of a specialist or experienced mason. Their input will prove invaluable to ensuring you follow the right process.

Making the mortar mix shouldn’t be done in large quantities. Instead, doing it in batches helps ensure it doesn’t harden fast. The cooler months of the year are ideal for carrying out this (chimney repointing) task.

  • Inserting New Mortar

You’ll need two trowels (large and pointing) for the job. Mortar should be loaded onto the large trowel while the pointed trowel is used to work smaller amounts into the gaps between bricks.

An additional tool known as the margin trowel can be used for vertical joints as these are more difficult to fill compared to vertical joints.

While evening out the new mortar between the gaps, it’s important to also clean or scrapes off any mortar on the face of the chimney bricks. This ensures a decent and clean job.

  • Tidying Up

Some tidying will need to be done after inserting the mortar. However, the new mortar must be allowed to harden a little before going any further. Cleaning up involves scraping off any remaining mortar on the face of the brick.

When scraping off excess mortar, it’s best to do so using a horizontal motion to avoid pulling out mortar from the joints. With this action successfully done, the wall should be gently sprayed with water for a maximum of 4 days.

Applying a fine spray of water on the chimney walls enables the mortar to dry out slowly without cracking.

Cost Involved

The cost of getting your chimney repointed will depend on the action taken.

In other words, adopting the DIY approach will cost you anywhere from $175. This includes the cost of materials as well as renting the scaffolding needed for the job.

On the other hand, calling for professional help such as a handyman or mason will attract costs starting from $849. This cost covers labor and materials.


The outlined procedure for chimney repointing may seem difficult but it is an effort worth taking. You’re able to keep your chimney in shape while ensuring a longer lifespan.

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