How to Repair a Spalling Brick Chimney

Moisture is the Achilles heel of unsuspecting brick chimneys. Bricks by nature are a porous material that absorbs water like a sponge. Although bricks are manufactured with a hard outer shell, environmental conditions can damage the surface allowing water to penetrate. High pressure and sandblasting can also pierce its protective shell.  And when water freezes the hydrogen atoms trapped inside the brick create a bond so strong that the water molecules expand approximately nine percent cracking the clay material. Left untreated tiny holes and crevices in the bricks become large cracks that continue to chip or spall from the chimney and crown structure. As the deterioration increases you will likely notice large gaps of missing brick and mortar around the chimney and crown.

How to Prevent Spalling Bricks

So how do you prevent seemingly harmless water from spalling your beautiful brick chimney? Your first line of defense is to apply a waterproof sealant that will allow the chimney to breathe while preventing water from seeping into the bricks. Also, the waterproof sealant will need to be re-applied every three to five years to ensure your chimney remains protected.

Before applying a waterproof coating it is important to first have your chimney inspected by a certified chimney sweep. The chimney sweep will inspect the entire structure including the flue and crown to determine the source of the moisture and the extent of any damage. There could be cracks in the flue and other damages in the chimney that could be allowing water to leak inside the chimney. This could pose a safety hazard when using the chimney so it’s important to contact a chimney sweep at the first sign of brick spalling.

Repairing Spalling Bricks

If your brick spalling is in the beginning stages and is relatively minor, the chimney sweep will likely recommend applying a waterproof sealant every few years to safeguard the chimney and prevent further deterioration. You will also need a level I safety inspection every year to make sure the spalling brick is under control.

In more severe cases, the spalled bricks will need to be repaired or even replaced to remediate the problem. The chimney crown may need to be re-built if brick spalling is extensive and beyond repair. In addition, any damages or gaps in the mortar will also need to be repaired in a process known as tuckpointing.

Once the spalled bricks are repaired you will have a beautiful chimney that will be as good as new and ready to keep your family warm and cozy in time for winter.

Spalling bricks is one of those problems that doesn’t go away and only gets worse (and more expensive to repair) over time. Contact us to schedule an appointment with a certified chimney sweep today!