Stamping in Cold Weather by Chris Camara
Contractors working in the northern United States and Canada have three words of advice when it comes to stamping concrete in cold weather: Wait until Spring.
While residential customers can often be persuaded to wait for more favorable conditions, some commercial projects must get done no matter how bad the weather gets.
Considerations for winter stamping include not only temperature and humidity, but the condition of the subgrade, the cementitious content of the concrete, different set times, and freeze-thaw cycles after the job is complete.
Ian Paine, marketing director for Lafarge North America, says it’s not unusual to do flatwork in cold temperatures as early as September in Canada. He suggests covering the subgrade with an insulated tarp, or at least a straw and tarp combination, to keep the moisture out ahead of time. A cold subgrade will pull the heat out of concrete, so one of the best things to do is to use content that is more cementitious, which creates more internal heat and helps the setting process, he says. Use high-quality concrete such as Lafarge’s Artevia for decorative work, he says. “Don’t go on the cheap. Any quality issues that you have will affect the growth of the decorative concrete industry in your area and certainly your own business growth.”
Lafarge’s Weathermix can extend the construction season, he says, because it is formulated to withstand a wide range of cold weather and some subfreezing ambient temperatures. And it speeds up set times, which are seemingly interminable during cold weather.