Cold Weather Conditions

  • Understanding that the first 24 hours are critical and that reducing saturation is the key to frost resistant concrete we examine appropriate methods to cold weather protection.
  • During the winter, however, when air temperature is below 50°F, atmospheric conditions in most areas will not cause undesirable drying; but, new concrete is vulnerable to freezing in a saturated condition, and therefore, should be allowed to undergo some drying before being exposed to freezing temperatures.
  • In contemplating the type of protection for the first 24 hours, first, consider drying to reduce saturation and second, allowing for adequate protection against the forecast low temperature.
  • Since most of the heat of hydration of the hardening cement in developed during the first three days, no heat from outside sources may be required to maintain concrete at correct temperatures if heat generated in the concrete is suitably conserved.
  • Emphasis should be placed on conserving the heat of hydration with out introducing heat from outside sources. Outside heat sources can produce carbon dioxide which reacts with calcium hydroxide to form a chalky calcium carbonate on the concrete surface. Forced air may also cause excessive eflorescence on the surface of the concrete.


Types of cold weather protection include

  • Polyethylene plastic
  • Foamed vinyl blankets
  • Straw


  • Protection is needed for 24 hours. For forecast temperature lows 32°F to 18°F cover unformed surfaces with 4” loose straw.
  • When precipitation is forecast cover straw with polyethylene plastic.
  • For forecast temperature 18°F to 10°F use foam filled blankets to cover formed and unformed surfaces