Concrete in Winter: Don’t Overlook These 4 Simple Things

Craig Fosque | December 8, 2021

Cold and concrete aren’t best friends. But they can work together. Temperature has an enormous impact on concrete. Keep these 4 things in mind as you extend your pour season into Winter.

Cold Tools and Forms

It’s easy to leave tools or a form exposed to the elements. Anything left outside will become cold, which could mean trouble for your concrete. Cold surfaces (or even rebar reinforcement) in contact with warm concrete, creates a temperature gradient. These temperature gradients alter the way concrete sets up, potentially compromising its performance.

Placing Concrete on Frozen Ground

As water freezes it swells. Ground that is saturated with moisture works the same way. If you pour a slab or footer on frozen ground, the ground underneath is liable to change shape as it defrosts. This can cause settling, which often leads to cracks in the concrete. These cracks can be either unsightly or a warning sign of deeper structural failure.

If pouring concrete in touch with frozen ground it’s often best to get below the frost line to limit the impacts of settling.

Keep an eye on the time with those shorter winter days

Daylight

Daylight is critical to being able to not only see the work, but provides an invaluable boost to the temperature.

Winter days in the mid-Atlantic can be 5.5 hours shorter than in the summer months. Days are shortest in December, and gradually lengthen through January, February and March. Additionally, the switch in time zones can mean dusk starts before 5 PM.

Two Day Forecast

When working in cold temperatures, it isn’t just one day’s weather you should be watching. Cold slows down the setting time, which could stretch into the next day. Keep an eye on the forecast to ensure that the concrete reaches sufficient strength (3,500 PSI) before exposed to freeze/thaw cycles.

Want to dive deeper on the ins and outs of cold weather concreting: Cold Weather Concreting