A brick chimney isolated against the backdrop of a blue sky. The chimney has several spalling (crumbling/cracking) bricks

Spalling brick is a serious but common phenomenon marked by chipping, cracking, crumbling, flaking, peeling, and powdering structural bricks. It has various possible causes, although it’s typically caused by water infiltration and subsequent freezing and thawing. 

Every home and business owner needs to understand spalling because excessive brick breakdown can be a health risk to anyone in or near the structure. And if the spalling is extreme, structural collapse is possible.

In this article, we’ll cover everything you need to know about spalling in bricks, including how to identify it, what causes it, how to prevent it, and best practices for fixing it.

A brick is showing serious signs of spalling. It's crumbling and starting to fall off the wall.

Identifying Spalling Brick

You can identify spalled brick by its appearance and texture. You will generally see chipping, flaking, or peeling, and brick material falling from the wall or other structures affected by spalling. Texturally, it’s commonly brittle, fragile, or crumbly. These effects become more pronounced as the spalling progresses and the brick continues deteriorating. In many cases, you can powderize spalled brick with your finger.

Major Causes

  • Water Infiltration/Water Damage (Most Common Cause)
  • Improper Installation of Mortar
  • Salt Exposure
  • High-Pressure Power Washing
  • Inadequate Structural Insulation
  • Using the Wrong Sealants
  • General Weathering & Old Age

The primary cause of spalling in brick masonry structures is water infiltration. 

During rain or washing, water pools on the top edges of the bricks, especially if the mortar joint atop is inset, even to a small degree. The pooled water sits there, eventually soaking into the brick, which is a porous material. The water also saturates the mortar that is holding the brick structure together.

Then, during cold weather, that water inside the bricks and mortar freezes and thaws, which causes expansion and contraction. The small fissures and pits that the water entered and froze inside expand. This process repeats indefinitely, causing progressively worse damage that culminates in spalling.

Although spalling is most commonly caused by exposure to the freezing and thawing of water, rain, and even moisture from wet soil, it can also be caused by improperly installed mortar, exposure to salt, high-pressure power washing, inadequate insulation in the structure, and masonry sealants that don’t allow the porous brick to breathe. General weathering and old age also increase the likelihood of spalling in structural bricks and mortar.

Preventing Spalling

An employee from All Brick is using a wooden platform to inspect a brick chimney

Routine Inspections

While it’s not always possible to completely prevent spalling brick, there are various ways that you can minimize its occurrence by catching it early on. The best thing you can do as a homeowner is routinely self-inspect your home’s brick structures. Look for developing signs of spalling, cracked mortar, and/or mold and mildew, all of which can indicate problems that need attention.

You should also have a professional inspection performed at least once each year. Your masonry contractor will use ladders, cameras, and other equipment to thoroughly inspect your chimney, walls, and other brick-based structures. And if any of your bricks are beginning to spall, the situation can be addressed before the damage becomes extensive.

Applying Sealant

Another way to prevent brick spalling is to apply a sealant. Choose a breathable sealant that won’t trap moisture that can then expand when frozen. The sealant will help to reduce water absorption, mold and mildew formation, and ice and salt damage.

Additional Prevention Tips

You can also prevent brick spalling by:

  • Installing a snow and rain cap on your chimney.
  • Maintaining a fluent gutter and downspout system.
  • Improving the drainage in the soil near brick structures.
  • Keeping your plants pruned away from bricked surfaces.
  • Avoiding high-pressure power washing and abrasive cleaning techniques.
  • Routinely checking your home for water leaks and ensuring prompt repairs.

How to Fix Spalling

The process or techniques used to repair spalling bricks are determined by the extent of the damage. Generally, the process involves:

  1. Carefully removing any loose or flaking mortar and bricks with a chisel and wire brush.
  2. Using a low-pressure washer and softer brush to clean the treatment area.
  3. Allowing the treatment area to dry out completely (fans help).
  4. Replacing the spalled bricks with new bricks and fresh mortar.
  5. Applying a breathable sealant and/or stain after the mortar has cured.

Having a professional by your side during this process is essential. They can help you avoid common, costly DIY mistakes, including selecting the wrong type of mortar mix and applying an incompatible sealant. A professional will also have the right tools and experience to get the job done right the first time.

Schedule Professional Chimney Brick Repairs

If you’ve noticed spalling, turn to All Brick for professional chimney brick repairs. We’re a family-owned and -operated masonry company dedicated to keeping families safe throughout Macomb County, MI. Contact us today to get started with an inspection.

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