impert&ent28 Aug 2005

The word is typically used with reference to concrete that endures sub-zero tempratures. It can also refer to concrete floors that are disintegrating through the accumulation of lime or due to the movement of heavy loads across them. In the case of freezing, water near the surface of the concrete freezes, expands, and shatters bits of the surface.

Spalling also occurs with brick, but regardless of temperature. Bits of brick flake off, and sometimes rework an entire face. On older walls the entire surface develops a rough but pleasing character.

If you live in a freezing climate, take a close look at the surface of a concrete steps or retaining walls, particularly those with smooth-formed surfaces. Bits of edges that look like they've been knocked off are likely spalls.