Spalling: Definition (Concrete Spalling and Repair)

Spalling Gallery: Click Image Below to Enlarge

concrete spalling near a drainage way on a sidewalk from freezing water conditions

spalling concrete closeup with exposed rocks

concrete sidewalk spalling with serious damage

spalling on a concrete sidewalk with cracking

concrete stairway with spalling showing on the landing and steps, as well as cracking and signs of a need for mud jacking

closeup of concrete spalling near a control joint

The Definition of Spalling, How it's Caused, and a Gallery of Concrete Spalling Pictures

Spalling: the word used for concrete that is chipping, flaking, or scaling damage along its surface.

This damage is most commonly found on outdoor concrete, which is often exposed to moisture and cold, but it can also occur with indoor concrete as well.

Where Concrete Spalling Occurs

When concrete is placed on a sidewalk, garage floor, or anywhere else, it is mixed with gravel. However, the gravel is ugly and unappealing to look at, so responsible contractors will attempt to touch up the surface to make it look smooth and white.

To do so, they add a small amount of extra water to the concrete surface and create a "cream" of pure concrete on the visible surface, which is the clean, white finish you see when the concrete has dried.

This cosmetic "creamed" surface is more fragile than the rocky concrete below, and it's the first layer to chip and flake away over time.

Causes of Spalling in Concrete

Concrete Spalling can be caused by a number of ways, but the three most common ways are as follows:

Freezing Water: Rain and melting snow will seep through the top layer of the concrete, polling underneath. When this water freezes, it expands and pushes upwards. This pressure causes the top layer of the concrete to spall, creating chipping, flaking, scaling, and similar concrete damage.
Rock Salt forming Subflorescence: When too much rock salt is used as de-icer on concrete, it will collect underneath the "creamed", finished layer of concrete. This salt will crystallize, creating pressure on the top layer of concrete and leading to spalling.
Rebar Corrosion: When rebar becomes moist, it will begin to rust and corrode. As it does so, it will also create pressure on the concrete, leading to spalling and cracking.

Spalling Prevention

A concrete sidewalk that's been badly damaged by runoff water from the roadside over the winter

Concrete spalling is made even worse when the rebar is affected by water and begins to rust or corrode. This corrosion expands the rebar, causing it to put pressure on the concrete from the inside. This will spall the concrete even faster.

All three of these causes are related to water and moisture making its way through the top surface of the concrete and directly or indirectly leading to damage in your concrete. When water is kept from making its way through the finished surface of concrete, it will not freeze in the concrete, bring de-icer into the pores, or do damage to the rebar.

One effective way to prevent spalling concrete is to apply Concrete Treat as a concrete sealer on your outdoor and indoor concrete.

Concrete Treat will react with the concrete, forming a glass like silicate bond deep within its pores. This prevents water, liquidated de-icer, and staining materials from seeping into your concrete. It may be applied with a brush, sprayer, or roller, and it dries in about 2-4 hours.

Concrete Treat is appropriate for both indoor and outdoor use, and it's available worldwide. Stop by our online store for prices and product availability today, or contact us by phone or e-mail with any questions or concerns. We're available by phone during normal business hours, EST.