The Effects of Deicing Agents on Stone and Terrazzo Flooring


As we welcome in Spring and begin to remove protective mats and rugs from floors and entranceways, the crystallization of many deicing salts and spreading of sand may have caused deterioration of the stone, terrazzo and masonry surfaces. This effect is called subflorescence. Snow and ice melters containing Calcium Chloride, etc. are the cause of this damage. Problems associated with subflorescence can be diagnosed and identified by visual clues, such as spalling and pitting.

The deposit of salts in the pores of stone and masonry is the major cause for deterioration of these surfaces. These salts are contained in many popular snow and ice melters. The water wicks into the pores of the stone and masonry carrying the salts with it. When the water evaporates the salts recrystallize. The pressure created in the pores of the stone and masonry cause the surface to flake off or spall. This process is known as subflorescence.

We at Marble Renewal can recognize the signs and symptoms of the damage caused by deicing salts. The stone and masonry will appear pitted or spalled. This damage is typically observed in the walking path at the entrances of buildings and homes. Certain stones such as some limestone’s and slates will flake off in sheets. Terrazzo and marble will become pitted.

This is the time to have Marble Renewal inspect the floors and have them restored to their natural lustre and finish. The goal of the restoration project is to rejuvenate the surface, refinishing it to a highly reflective level where it is clean; safe; feels smooth to the touch, shows the beauty of the surface through vibrant depth and colour, and becomes easy to maintain. The steps performed vary according to the type of finish you want to achieve— high gloss, honed or flamed.