Spalling brick is a common problem that occurs when the masonry surface begins to flake or peel. This can be caused by a number of factors, including freeze-thaw cycles, exposure to salt, and exposure to moisture.
What is Spalling Brick?
Bricks are an especially resilient building material and are typically maintenance-free for decades. However, under specific conditions, the face of a brick may pit, flake, or crumble and fall away from the body of the masonry. This is called spalling and it regularly starts as small cracks that grow into larger crevices until the entire service of the brick deteriorates.
What Causes Brick from Spalling?
Spalling occurs when moisture from rain, snow, and even wet soil saturate and penetrate the masonry surface. Bricks are similar to a sponge and continually pull in and expel moisture. When the temperature outside cools down, moisture within masonry will freeze and expand. As the temperature rises, the water thaws and decreases in volume. The process is called a freeze-thaw cycle and it causes brick to crack and eventually spall as the fractures widen.
Other causes of spalling brick include:
- Improper insulation
- Non-breathable masonry sealants
- High pressure washing
- Impact
- Weathering
Spalling is more likely to occur around leaky windows, damaged chimneys, around doors or stairs, or any other areas where moisture is trapped behind masonry. Similar to spalling, loose brick can also be caused by changes in temperature. Hot, cold, wet, and dry conditions can cause the masonry structure to move, resulting in holes in the mortar. The holes allow moisture to penetrate the masonry wall and can cause the bricks to loosen.
Other areas prone to spalling brick include:
- Near or around faulty gutters and downspouts
- Around mortar joints
- On the lower half of brick walls
- Basements
- Around the foundation
- Brick that is covered by soil or dirt
- Damaged chimney
Are Spalling Bricks Dangerous?
Crumbling masonry is not simply a cosmetic problem, it’s also a safety risk. Bricks that are deteriorating often pose a health risk to people inside as well as outside of the home. Brickwork is designed so that each brick supports adjacent masonry. Once spalling occurs, the surrounding bricks are at risk of failing. The masonry will weaken and can be at risk of possible collapse.
The dangers of spalling brick include:
- Health risks caused by mold due to water infiltration
- Structural collapse
- Damage to other parts of the structure
How to Stop Brick Spalling
Once bricks begin spalling in a specific location, the surrounding masonry is put at risk. It’s best to prevent spalling before it occurs. One of the simplest ways to mitigate your risk of spalling brick is to apply a breathable masonry sealant. Stayntech® manufactures a breathable top-coat matte sealer that repels moisture and other liquids as well as provides protection against UV damage.
By reducing the absorption of water, a varied range of issues caused by the freeze-thaw cycle can commonly be avoided including cracking, pitting, staining, ice and salt damage, the growth of mold and mildew and, of course, spalling. Spalling can also be prevented by ensuring there is proper drainage around the exterior of a home or building so that water does not accumulate near the foundation.
Other tactics to prevent brick spalling:
- Install a snow/rain cap on your chimney
- Check your home for leaks and make repairs immediately
- Inspect your brick and chimney regularly for cracks and replace spalling bricks
- Prune back crawling vines as they can trap moisture