With cold weather in the air and more to be expected, the Missoula Building Department wants to remind all contractors to ensure Missoula's cold weather concreting requirements are being adhered to. The below requirements apply immediately following concrete placement and are based on anticipated daily temperatures according to the National Weather Service Forecast Office. Protect concrete placement in the following manner:
- 40 F to 32 F: Protect newly poured concrete by covering it with a weather-resistive membrane for 24 hrs.
- 32 F to 20 F: Cover newly poured concrete with a weather-resistive, insulating blanket, or equal, for 24 hrs.
- 20 F and below: Maintain newly poured concrete above 32 F for a minimum of 5 consecutive days, immediately following placement, through the use of heated enclosures, electric concrete blankets, or other acceptable methods.
- Concrete is not allowed to be placed on snow or frozen ground.
- Contractors may submit their own cold weather plan for approval by the Building Official.
These guidelines are a generalization of the American Concrete Institute (ACI) requirements and are not to be used as the sole means to ensure compliance with the code. Please refer to ACI 306 for complete cold-weather concrete placement requirements.
Best regards,
Missoula Building Division