For a brick chimney, cracking is one of the most obvious signs that there is an underlying issue that needs to be addressed. Cracking doesn't just present aesthetic issues, but it also puts the structural integrity of the chimney in a vulnerable state, which introduces a number of safety concerns. If you recognize any cracks in your foundation, it's important to get to the bottom of the issue so that you can have the necessary repairs performed.
If your chimney is relatively new and you are having issues with cracking, poor construction could be to blame. When building a chimney, it's important to leave space between the masonry chimney sides and the flue lines. When you operate your fireplace, this causes the flue to also heat up.
This increased heat causes the bricks to expand. Leaving air spaces helps accommodate this expansion process. If this space is absent, as the bricks expand, they will press into one another and cause small cracks that get deeper and longer each time you operate your fireplace.
Another reason you might be recognizing cracks in your chimney is foundation movement. Poor installation, maintenance or changes in the ground around the foundation can cause the foundation to shift. Even the slightest adjustment in the foundation can cause a crack in the chimney along the mortar joints.
When dealing with this type of issue, while it's important to repair the cracks in the chimney, the more important task is to get to the bottom of the foundation issues. Otherwise, the cracks will only reappear until the foundation has been repaired.
Repairing A Crack
The location of the crack will determine what repair method is applied. A crack in a brick chimney will occur either within the surface of a brick or the mortar joints. If the crack is in the actual brick, this will generally require that the entire brick be replaced. Repairing a brick in this condition isn't safe because this still leaves the structural integrity of the brick in jeopardy.
For a crack that is in the mortar joint, this involves the removal of the outer layer of the mortar. Once it has been removed, new mortar is installed in the damaged area, where it is allowed to set and stiffen.
If your brick chimney is cracking, make sure you have the issue addressed promptly to prevent further damage and eliminate safety hazards. Contact a business, such as Excel Chimney & Fireplace Service, for more information.