What is spalling in concrete?

Spalling refers to the flaking, chipping, or breaking away of concrete surface material, typically in pieces ranging from small fragments to larger chunks. The damage exposes the interior of the concrete and often becomes visible as pitted or cratered sections on driveways, steps, patios, or other hardscapes.

In the Charlotte Metro area, spalling commonly develops through three mechanisms. Freeze-thaw cycles occur when water enters concrete, freezes in winter, and expands with enough force to break the surface. Deicing salts applied during icy weather penetrate the concrete and lower the freezing point of water inside the material, accelerating this cycle. Rebar corrosion happens when moisture reaches the reinforcing steel within the concrete, causing it to rust and expand, which pushes outward on the surface layers until they break away.

Spalling matters because it signals ongoing deterioration. Early surface spalling on a driveway may seem cosmetic, but it indicates that water is moving through the concrete. If left unaddressed, water continues to work deeper, worsening the damage and shortening the concrete's useful life. On structural elements like steps or entryways, spalling creates safety hazards and trip risks.

Contractors specializing in concrete repair and resurfacing can address spalling through patching, sealing, or in severe cases, full replacement. Early repair prevents costlier failure later.