Tech Tips: Cold Weather Concrete Installations
Before winter begins, many customers consider installing a snow melting system to relieve the need for shoveling or plowing. And, with unprecedentedly warm weather in the Midwest region of the U.S., snow-melting installations continued well into the winter months, when the installation season usually ends in the early fall months. As many of you know, the installation process for a snow melting system is done best in weather above 50° F and below 90° F. When the weather is colder, installing one of these systems and pouring concrete can be risky and increasingly more difficult.
Concrete is known to be very sensitive to temperature. As the weather becomes colder, concrete tends to set up more slowly and it takes longer to complete. But the riskiest part of pouring concrete is the threat of it freezing.
And, so we thought that we would give some advice on how to do cold weather concrete right:
In order to cure the concrete correctly and reach its optimal strength, concrete should be laid down when the temperature is above 50° F. The longer the concrete has to cure, the stronger it will be, which in cold weather causes a dilemma because of the risk of freezing. Temperatures below 50 F° will slow the hydration process, extending the time and ultimately causing a higher risk of freezing. One additional way to speed up curing and reduce the risk of freezing is to use accelerants, using accelerants can be helpful but may add a risk of cracking or spalling in the concrete.
Ice starts to form in fresh concrete when the concrete temperature approaches 27° F. When the water in fresh concrete freezes, the ice takes up more space than water does, resulting in an expansion of volume in the concrete. As a result of the damage done by the ice formation, the final compression strength can reduce as much as 50 percent.
While laying down concrete, your first goal is to keep the concrete from freezing until most of the water is gone, and when it reaches the strength of 500 psi. The easiest way to protect concrete against the cold and to prevent freezing is by proper insulation. To insulate the concrete, you can either use curing blankets in order to maintain heat and moisture or you can use heaters around the area where the concrete is laid.
Also, what many people may not know is that you have to keep the cables in the snow melting system warm, as well. Cold temperature during installation can make the cable jacket and the conductor too brittle, increasing the risk of cracking and possible system failure. When installing a snow melting, slab heating, or floor heating system, it is important to be cautious if you are installing the system at a temperature below 32° F.
Remember, if you’re installing one of our radiant heating systems, we are here to help you 24/7. Call us at (800) 875-5285 with your installation or technical questions. We are here to serve you!
Everything works better with a little warmth.