The Causes of Spalling Bricks

Chimneys are exposed to the elements year-round — from excess rain to turbulent thunderstorms, and heavy freezing snow, the northeast experiences it all. As masonry ages, there could be several issues homeowners may notice. A potential brickwork issue you may see on your chimney is spalling.

This may look alarming at first, but it isn’t uncommon, and it is something that can be repaired or rebuilt.

What Is Spalling?

Spalling bricks refers to the process of the brickwork breaking down. This can show itself in several ways, such as peeling, cracking, chipping, or even crumbling. If left unattended, it can lead to bricks falling away from the structure.

Like most issues, it can progress as it experiences more testing of natural elements like excessive rain or snow. Luckily, it doesn’t immediately indicate structural issues; at the beginning it could simply be aesthetic.

How Does Spalling Bricks Occur?

Spalling bricks is caused by water ingress, or water absorption. Bricks are porous so they can absorb water and moisture. A little absorption is normal because it can dry out, but some bricks are more porous than others so it can leave bricks saturated. Sometimes, this water can find its way inside your chimney as well.

Moisture absorption in bricks alone isn’t a tremendous reason for concern, however, if water is absorbed before a frost, it can cause damage. This is due to a process called a freeze-thaw cycle. Any water absorbed in the bricks or mortar of your chimney (through small fractures), can freeze if it’s subject to temperatures below freezing. As the water freezes, it expands, potentially making cracks larger or damaging bricks. When it thaws, it contracts and can cause even more damage. This is a primary and common reason for spalling bricks.

When Does It Become a Structural Issue?

Repeated exposure to the freeze-thaw cycle can potentially lead to larger, structural issues. Thankfully, if you perform annual inspections, your chimney professional may catch these issues in the early stages. Depending on the severity, you may be able to spot fix, such as replace bricks and seal mortar, to avoid larger structural issues. However, if leaning or crumbling has started occurring throughout the chimney it may require larger rebuilding. Additionally, if your chimney was poorly constructed or they used lower quality brick and mortar, you may be more apt for structural issues.

Unfortunately, this is something that is hard to know to the common eye, but experienced chimney professionals can come up with the best course of action based on your specific situation.

In need of spalling brick repair?

Fire N Stone is a full-service chimney service that can help if you’re experiencing spalling bricks. We’re the local, trusted team to call for assistance. No matter the severity of your spalling, our experts can handle it. We also support our clients with routine chimney maintenance, masonry repair, or even outdoor kitchen installation. We never subcontract our work, which means you work with the same trusted team the entire time.