Spalling brick is a common problem that occurs when the surface of a brick 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. Here, we’ll go over what spalling brick is, what causes it, and how to repair spalling brick.
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 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 mortar
• Improper insulation
• Non-breathable masonry sealants
• High pressure cleaning
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
• Around the foundation
• Brick that is covered by soil or dirt
• Damaged chimney
How to Repair Spalling Brick
Repairing spalling brick is a fairly simple process that can be done by a homeowner with the right tools and materials.
- First, remove any loose or flaking brick material using a wire brush or chisel. Be sure to wear safety goggles and a dust mask to protect your eyes and lungs.
- Next, use a pressure washer or a stiff-bristled brush and water to clean the affected area. This will remove any dust or debris that may be present and will help to ensure a good bond between the new mortar and the existing brick.
- Allow the area to dry completely before proceeding. If necessary, you can use a fan or dehumidifier to speed up the drying process.
- Mix a batch of mortar according to the manufacturer’s instructions. A high-quality, pre-mixed mortar is recommended for best results.
- Apply the mortar to the affected area using a trowel. Be sure to force the mortar into any cracks or crevices in the brick, and smooth the surface so that it is flush with the existing brick.
- Once the repair is complete, it is important to protect the new mortar from the elements by applying a brick stain (we’ll talk about this later on). This will help to prevent moisture from penetrating the brick and causing further damage.
- If the damage is severe, like cracking, it may be necessary to replace the affected bricks. This is a more difficult and time-consuming task and it’s best to leave it to the professionals.
It is important to note that while these steps can help in knowing how to repair spalling brick, the underlying cause of the problem should also be addressed. For example, if the spalling is caused by exposure to moisture, steps should be taken to improve drainage and ventilation around the affected area to prevent further damage.
Are Spalling Bricks Dangerous?
YES. 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.
BrickImaging applies a breathable top-coat matte sealer as the final step in its brick staining process. The penetrating sealant 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
Stain Your Brick with BrickImaging
Remember that last step in how to repair spalling brick? The best thing you can do for your brick is give it a protectant, like a staining.
BrickImaging has been permanently staining brick homes, apartment buildings, office buildings, retail plazas, schools, banks, hotels and more since 1976.
The company is the oldest masonry staining firm in North America and its proprietary Stayntech® brick stains look natural, do not block the evaporation process of masonry, and will never bubble, chip or peel.