What to Do About a Spalling Brick Chimney

“Spalling” is the term for chimney bricks when their surfaces flake and break off. A spalling brick chimney is evidence that moisture saturation has occurred. To prevent spalling, it helps to determine the underlying problem. Some of the reasons moisture infiltrates brickwork are below as well as tips on how to prevent spalling.

What Causes Spalling?

Bricks are porous and naturally tend to absorb moisture. If too much water gets in the masonry, the freezing and thawing cycles in winter cause the water to expand and contract, which results in spalling. If they aren’t replaced, the moisture-damaged bricks eventually flatten. 

When a chimney is built correctly, the mortar, chimney crown, and other components help to prevent moisture damage. The deterioration of those components can result in a spalling brick chimney. Other factors also contribute to moisture intrusion, as follows:

• The use of pressure washers and sandblasters can damage brick exteriors. As a result, the bricks are even more vulnerable to an infiltration of moisture.
• Using salvaged bricks in the construction of a chimney may increase the potential for moisture damage. Spalling is just one of the ways salvaged bricks tend to be problematic.
• The chimney crown is the top part of the chimney, and its job is to keep water out of the chimney system. The material used to make a chimney crown, however, isn’t nearly as durable as masonry. Deterioration of chimney crowns is a common reason that moisture saturation and spalling occur. 
• The layout of the rooftop in relation to the chimney sometimes causes a frequent inundation of the chimney with water. This can greatly accelerate the deterioration of masonry, resulting in structural damage such as spalling.

What to Do About a Spalling Brick Chimney

If you see debris on the roof around your chimney or on the ground below, it is evidence of spalling. Repair is needed as soon as possible. Bricks must be replaced when they have been damaged by moisture. Otherwise, the chimney structure will become unstable. 

Schedule an annual chimney inspection, which is usually required by most homeowners’ insurance policies, anyway. Qualified chimney sweeps can identify early signs of potential moisture problems. It is often possible to make repairs before you find yourself with a spalling brick chimney. 

Repairs that Can Prevent Spalling

Keeping moisture out of brickwork requires diligence. When expert chimney sweeps have identified areas of moisture vulnerability, the following are some actions that can be taken to possibly prevent a spalling brick chimney:

• When mortar has begun flaking off, address the problem before water gets into the masonry system. With a procedure called “tuckpointing,” expiring mortar can be removed and replaced with fresh mortar that keeps moisture out of the chimney system.
• When deterioration of the chimney crown occurs, schedule chimney crown repair or replacement as quickly as possible. 
• Install a “cricket” on the roof. A cricket is a device that diverts excessive water away from your chimney.
• Have a chimney cap installed or as needed, schedule chimney cap repair or replacement. 

Contact Fire N’ Stone for Chimney Inspections and Repair

Chimney maintenance is the best way to prevent conditions that result in a spalling brick chimney. Schedule a chimney inspection and cleaning with Fire N’ Stone and make chimney repairs, as needed. Our highly trained chimney specialists provide your best opportunity to avoid the future expense of a partial or complete chimney rebuild due to moisture intrusion.

Call us at 603–293–4040 today or use our online form to set up a convenient appointment time.