Brick Spalling: What To Do About It

Advisory Report - February 2004

Brick Spalling: What To Do About It

Spalling. Most people have never heard of it before. But there's a good chance that you've actually witnessed it on your own home or on the home of someone you know. When a brick has not been fired at a high enough temperature, it can absorb water, which then expands during cold temperatures, causing the brick face to peel away. This is called "spalling."

One of the main causes of spalling bricks near the top portion of a chimney is a defective masonry cap. Often times the cap is cracked allowing water to enter into the brickwork below. Spalling can also result from cracked and open mortar joints between the bricks.

The only way to control the problem is to stop the water from penetrating into the chimney. Damaged areas of mortar should be removed and fresh mortar installed. Some people recommend applying a waterproofing agent, such as silicone, to the chimney to prevent or reduce water absorption.

Click here to learn more about brick chimneys.

Contributed by Justin Gore
Quality Assurance Supervisor
U.S. Inspect, LLC