Brick and Concrete Spalling: Causes and Effects

Spalling is a common problem for concrete and brick that is often overlooked by homeowners or mistaken for an aesthetic issue. While it is often only cosmetic, when unchecked it can develop into more serious conditions. In order to fully address spalling and take appropriate next steps on a claim, it’s important to know what may have caused it and its potential long-term effects.

Spalling on concrete or masonry like this brick manifests as seemingly minor aesthetic damage, but failure to address it could lead to further structural issues in certain types of construction.

Concrete Spalling

Concrete walls, foundations, sidewalks, and driveways are all vulnerable to spalling. On concrete, this looks like flaking, cracking, chipping, or even undulation.

Despite appearances, concrete is a porous material, meaning that moisture can absorb into fine capillary spaces. When the temperature drops, any water in the concrete freezes and expands, creating a pressure that forces flakes on the top concrete layers to loosen and separate. This process is repeated when the temperature fluctuates from below freezing to above freezing, so it could be exacerbated with the use of deicing products, which increase the number of freeze-thaw cycles.

Water can also play a part in spalling in concrete that is reinforced by rebar. Moisture exposure can cause the metal, often steel, to rust and expand. This steel expansion is referred to as oxide jacking. When it does so, it exerts force on the surrounding concrete, eventually causing it to break down and crack or flake off.

When water absorbs into concrete and freezes, expanding, the pressure it exerts on the concrete can lead to spalling, like the pitted surface of this sidewalk.

While moisture is the most likely cause of spalling, it’s not the only possibility. Exposure to ammonium fertilizers, which react poorly with components of concrete, can contribute to the process, particularly around foundations and landscape-adjacent walls. Policyholders may also see spalling as a result of improper installation, including:

• Temperatures outside of an acceptable range during installation
• An improper concrete mix
• Improper sealing or finishing

Brick spalling

Like concrete, brick spalling is often caused by expanding water that has permeated the bricks’ surface. Water, rain, snow, and roof splatter can all factor into spalling. It most often occurs near excessive water, like near the ground, along the bottoms of parapet walls, around roof drains, and at the tops and sides of chimneys. Bricks that were improperly sealed and insulated, or those undergoing age-related deterioration are particularly susceptible to moisture damage. Saltwater is especially harmful for both brick and concrete, so coastal areas and locations that frequently use rock-salt treatment to melt snow are most at risk.

Spalling is more likely to be overlooked in brick than on concrete, as it’s a less uniform material and early stages of delamination may be so thin as to be mistaken for part of the design. More severe spalling takes the form of chipping, flaking, peeling, or even detaching. Spalled bricks can also feel brittle to the touch.

Effects of Spalling

Most spalling is cosmetic. However, the process peels away protective layers, leaving the brick or concrete more exposed and vulnerable to additional damages. Moss, mildew, and other organic growth can enter spalled materials, causing more flaking and widening fractures as it spreads.

In extreme cases, bricks and concrete can crumble enough to compromise the structural integrity of the wall, leading to partial or full collapse. This may extend beyond the affected area if a wall is loadbearing. Moreover, severe spalling has the potential to present safety concerns, as falling masonry can lead to serious injuries or even fatalities. Because spalling can worsen, it’s important to determine the extent of damage and to get repair or replacement recommendations from a qualified expert.

Repair Options for Spalling

Some recommendations for addressing spalling may include:

Tuckpointing. Tuckpointing is a repair process that entails removing damaged mortar joints, filling the gaps with new mortar, and resealing it to strengthen the protective layer.

Patching small areas. If the impacted area is limited, it may be sufficient to repair by resurfacing it with an appropriate dressing.

Replacing damaged rebar. If rusted rebar is responsible for the spalling (and the associated moisture has been addressed), replacing the affected concrete and rebar can be necessary to maintain the concrete members structural integrity.

Full replacement. If spalling is severe, the best course of action may be to replace the entire wall or slab.

In severe cases where rusted rebar leads to spalling, full concrete replacement may be needed.

Only a professional familiar with spalling, its causes, and the materials it impacts can offer expert advice on how to address it. Donan’s forensic engineers can identify the scope of damage and provide recommended actions to return the brick or concrete to pre-loss condition. Submit an assignment for answers about spalling and other structural damage claims.

Alpine Intel’s content is meant to inform and educate readers using general terms and descriptions. They do not replace expert evaluations that determine facts and details related to each unique claim.