Home Fix: Dwight Barnett answers home-improvement questions. This week's topic is on flaking or spalling bricks.

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Q: You have written about spalling or flaking bricks and why they’re that way.

You said a cap of stone, wood or metal is needed to keep rain and snow out. Would you please explain what kind of cap you’re talking about? This is happening to the brick on the north side of my house in Texas.

A: Most all bricks will store water when exposed to rain or snowmelt. During the drying process, the stored water travels to the surface of the brick, and when the weather turns to freezing the stored water turns to ice, which expands and damages the face of the bricks.

This appears more often on bricks above grade on chimneys and retaining walls, but brick walks and patios with poor drainage can also be damaged by “spalling.”

To prevent water damage to the brick surface and to the mortar joints of vertical walls or chimneys, a cap of precast concrete, limestone slabs, terra-cotta tiles or fabricated aluminum is often used much like an umbrella to protect the bricks below. The roof of a home helps protect the exterior bricks from the weather, but a wall capped with bricks will have multiple joints exposed to water entry.

Caps of stone, concrete or tile will also have joints along the top of the wall that will have to be maintained annually to prevent spalling.

The caps made of stone, concrete or tile should also have an overhang on each side of the wall to form a drip ledge to prevent water from cascading down the face of the brick. Aluminum can be formed to any shape needed to force water away from the brick’s surface; however, certain metals can leave a stain on the bricks that would require additional maintenance.

Brick is a durable and architecturally pleasing product, but it must be installed properly and receive, at a minimum, an annual inspection for defects in the mortar joints and surface finish.

Dwight Barnett is a certified master inspector with the American Society of Home Inspectors. Write to him with home-improvement questions at d.Barnett@insightbb.com.