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Concrete Patio Scaling and Flaking: call a concrete mason — or fix it yourself

Concrete patio scaling — where the surface layer peels, flakes, or pits in thin sheets exposing rough aggregate underneath — is a freeze-thaw durability failure that worsens every winter. The damage typically starts as small, shallow pop-outs or rough patches and progresses to large sections of missing surface over two to three seasons. The primary cause is water penetrating the top quarter-inch of concrete, freezing, expanding by roughly 9%, and physically breaking the surface layer away from the denser concrete below. Three conditions accelerate scaling: inadequate air entrainment in the original mix (the concrete lacks the microscopic air bubbles that give ice room to expand), premature finishing (troweling the surface while bleed water is still present seals a weak, high-water-ratio layer at the top), and deicing salt application during the first winter (sodium chloride and especially calcium chloride increase the number of freeze-thaw cycles the surface experiences and chemically weaken young concrete). Once scaling has started, no sealer or coating will reverse the damage — the delaminated surface must be removed. A concrete mason can assess the depth of damage and recommend either a bonded overlay (a thin cementitious or polymer-modified layer applied over mechanically prepared existing concrete) for shallow scaling under half an inch, or full removal and replacement for deep or widespread damage. Preventing future scaling requires specifying 6–7% air-entrained concrete with a maximum water-cement ratio of 0.45 and avoiding salt for the first winter.