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Fireplace Brick Repair Guide: How To Fix Fireplace Cracks


If you have a fireplace in your home, it may need repair at some point in time. In this post, we will explain, step by step, how to fix fireplace cracks. A fireplace can be a beautiful centerpiece or focal point of a room and should last for years if maintained properly. There may come a time, however, when your bricks may get cracked and require repair. If you find yourself in that situation, and would rather have a professional fix the problem, contact the expert stone masons at Royal Masonry.

Parts Of A Fireplace

Whether you have an outdoor or indoor fireplace, itis made up of three basic parts:

  1. Firebox
  2. The Damper and Chimney System
  3. Fire Brick Liner

The fire brick liner provides a buffer between the fire and the firebox. In a masonry fireplace, individual firebricks are used to make the firebox; in prefabricated metal fireplaces, refractory brick panels line the firebox. The fire bricks that are used to construct the liner are specially designed to absorb high temperatures, thus preventing damage to the wall behind the fireplace. After years of use, fire bricks and mortar can become damaged or cracked. This is a potential fire hazard and therefore should be repaired or replaced before using the fireplace again.

The following video further demonstrates why it is important to check the fire bricks in your fireplace for cracks or damage.

How To Fix Fireplace Cracks

In this post we will look at 3 different areas where problems may occur and how to fix them. These include: how to replace refractory mortar, how to repair a cracked firebrick, and how to replace refractory brick panels.

How To Replace Refractory Mortar (Tuckpointing)

If the mortar around your fire bricks is damaged or beginning to crumble or if you are replacing a damaged fire brick you can remove and replace the mortar as follows. This process is also known as tuckpointing.

  1. Scrape out any loose mortar using a scoring tool, starting where the mortar is coming loose.
  2. Dig out the deteriorated mortar on both sides of the joint, 1/2″ to 3/4″ deep, until it is free of mortar.
  3. Use an old paintbrush or vacuum to clean the joints.
  4. Brush some water on the joints and brick faces. This is necessary because mortar will not stick to a dry brick very well.
  5. Mix your mortar according to the directions
  6. Apply mortar to the brick in line with the joint.
  7. Using a tuck-pointing trowel, pack mortar into the joint. Pack it about halfway full.
  8. Pull the pointing trowel along the joint, pressing firmly, until the joint is filled.
  9. Scrape off any excess mortar from the brick faces and then quickly wipe with a damp sponge.
  10. Let the mortar dry completely for several days.
  11. After it is dry, you can rough it up with a metal chisel so it matches the existing mortar.

Source: How do I Repair my Fireplace’s Fire Brick?

The following video shows you how to repair mortar that has deteriorated inside a fireplace.

How To Repair A Cracked Firebrick

If any of your firebricks are cracked or broken, you can either replace them with a new brick or you can try repairing them as follows:

  1. Clean the brick that needs repairing, removing any soot, grease, or dust.
  2. Let the brick dry thoroughly.
  3. Using a trowel, apply fire cement to the damaged area.
  4. If the brick has broken in more than one spot, put a layer of cement along the edge of each break and firmly push the pieces back together.
  5. Clean off any excess cement.
  6. If you are repairing a crack, push the cement into the crack and remove the excess.
  7. Gradually heat the brick over a three to four hour period.
  8. Let the brick cook. If there are further cracks, repeat the above steps.

Sorce: How do I Repair my Fireplace’s Fire Brick?

How To Replace Refractory Brick Panels

The following video shows the steps required to replace refractory brick panels in a fireplace.

If the panel of your prefabricated metal fireplace develops a crack, you will need to replace the panel as follows:

  1. Remove the old panel by unscrewing the screws holding it.
  2. If you are replacing a back panel you will need to remove the side panels first.
  3. Write down the numbers on the metal plate inside the opening of the firebox so that you are sure to order the correct replacement panel.
  4. Install the new panel, making sure that it the corners fit snugly against each other
  5. Refractory mortar is not usually required.

Source: How To Fix Fireplace Cracks

When To Contact A Professional

If the majority of the fire brick and mortar in the firebox needs repair, and the integrity of the structure is in question, it is best to leave the job to a professional. If you are looking for a qualified stone mason in the Kitchener-Waterloo region, contact the professionals at Royal Masonry. We are the region’s stone masonry experts. You can trust us to repair or replace any damaged areas of your fireplace. We have years of experience and know-how when it comes to any type of masonry project and our customers have come to rely on us for high quality work at a fair price.