Snow and Cold. What does it mean for your concrete project?
Welcome back to Kansas City with a snap of cold and more snow! What’s one or two more snow days for these kids on top of the 6 we have already had!?
It’s no secret that precipitation and cold weather have big impacts on all construction projects timelines, especially in the concrete world. Let’s review some of the variables, impacts, and options for overcoming these difficulties with a knowledgeable concrete contractor.
Pouring Concrete in Cold Weather
One of the most common questions about pouring concrete in cold weather is: "How cold is too cold?" In Kansas City we know the weather is incredibly unpredictable. From 50 degrees one day to -10 degrees the next, there is no such thing as consistency here.
According to the American Concrete Institute (ACI), cold weather for concrete occurs when:
The average daily temperature is less than 40°F (5°C)
The air temperature does not exceed 50°F (10°C) for more than 12 hours in a 24-hour period
When temperatures drop below these thresholds, extra precautions are essential to ensure your concrete sets and cures properly, achieving long-term strength and durability.
Why Cold Weather Affects Concrete
Concrete requires heat to set and cure effectively. Cold weather slows down the chemical reaction of hydration, which hardens the concrete. If concrete freezes before it has gained enough strength, it can weaken and lead to cracking or surface failure.
Tips for Pouring Concrete Successfully in Cold Weather
Prepare the Site Properly
Clear snow, ice, and frost completely from the work area.
Never pour concrete on frozen ground, as it will thaw unevenly, leading to settling issues and cracks.
Timing Is Everything
Schedule the pour for early morning to take advantage of the day's sunlight.
Use a Low Slump and Minimal Water-to-Cement Ratio
Less water in the mix reduces the risk of freezing and shortens the set time.
Add Accelerators to Speed Up the Set Time
Use products like SpeedSet or calcium chloride (no more than 2% by weight of cement) to accelerate curing.
Use Heated or Insulated Mixes
Request a heated mix from your concrete supplier if possible.
Insulate the Concrete
Use concrete curing blankets to keep the concrete warm and maintain optimal curing temperatures.
Keep the concrete from freezing for at least 3 to 7 days depending on weather conditions.
Pre-Warm Embedded Materials
Ensure rebar, wire mesh, and other embedded items are above freezing temperature before placement.
Avoid Premature Finishing
Do not start finishing operations until all bleed water has evaporated.
Consider Heated Enclosures
Set up temporary heated enclosures when necessary.
If using combustion heaters, ensure proper ventilation to prevent carbonation damage to the concrete surface.
Waterproof and Seal the Surface
Use a waterproof concrete sealer as a curing compound rather than traditional water curing methods.
**** Avoid De-Icing Salts on Fresh Concrete ****
De-icing salts can corrode the surface, allowing water to penetrate, freeze, and crack the concrete. Instead, use sand or non-corrosive traction aids.
Know when it’s time to re-schedule or delay
If extreme cold weather persists, professional contractors may also implement ground-heating techniques or delay the project for optimal weather conditions. Proper planning ensures a stronger and more durable final product. The worst thing a contractor or homeowner can do is rush the project in poor conditions creating instant issues with the durability, appearance, and overall quality. Even in circumstances where it looks good at first, there can be delayed defects that cause early cracking, chipping, fragility, and other major problems.
By following these best practices, you can confidently pour concrete in cold weather and achieve professional-quality results. At A Cutt Above Concrete we know how to work with, in, and around cold weather to ensure you get the quality outcome you expect with your project. Make sure whoever you select for your home project gives the same level of knowledge and service!
Tyler
