Bricks are useful in making fireplaces, steps, as an exterior covering for your home, monuments, pathways and other functions. They are a durable and strong building material. Spalling occurs in bricks as a result of different factors. It causes the bricks to crumble and reduce in size and strength over time.
Bricks with spalling have cracks and breaks in the surface and often large, crater- shaped chips. Other indications of spalling are loss of surface material and striations. Spalling often occurs in basements and around chimneys. If the damage is bad enough it may compromise the stability of the structure.
Moisture inside the bricks causes spalling. This occurs when the bricks are uncured or "green." Under very hot temperatures the moisture turns to steam inside the bricks, thus causing it to expand and leave cracks, breaks or chipped areas.
Fire damage causes spalling to occur in bricks as well. The rapid expansion of the brick during a fire and the intense cooling effect of the water to extinguish the flames causes the bricks to crumble, crack and otherwise deteriorate.
Prevention of Spalling
The best way to avoid brick spalling is to eliminate the moisture. Buy the bricks from a reputable dealer that sells only cured quality bricks. Hire a chimney sweep or qualified professional to inspect your chimney cap. If the area around your chimney cap is cracked or the cap itself is defective, this allows water to seep into the brickwork below. Seal these areas around the chimney with a silicone waterproofing agent or masonry sealant to eliminate or reduce the moisture problem. Open mortar joints and cracks in the mortar also cause water to penetrate the bricks. Add fresh mortar or have the cracks repaired by a bricklayer.
Repairing the Damage
If only a few bricks are damaged by the spalling it is wise to simply ignore the cosmetic detriment. The only way to repair spalling is to take out and replace the affected bricks. This is a costly and time-consuming job. Unless the spalling is near a focal point, such as the main entrance of your home or it affects the stability of the building or other structure, it is not serious enough to warrant replacing the bricks.