Pouring Concrete in Northern Ohio Weather

Concrete cares about temperature more than almost anything else on a job site. Too cold and it gains strength slowly or freezes before it can cure. Too hot and it sets before the crew can finish it. Northern Ohio gives us plenty of both.

The comfortable window

Concrete places and finishes best when air temperatures sit roughly between 50 and 80 degrees. Around here that usually means late April through October, with November depending on the year. Most residential flatwork gets scheduled in that window.

Cold-weather pours

Concrete can be placed in cold weather, but it needs help. Fresh concrete has to be protected from freezing until it has gained enough early strength, and that takes longer when it is cold. Common precautions include:

• Never pouring on frozen ground. The subgrade has to be thawed and stable.
• Heated water or accelerating admixtures in the mix so it sets and gains strength faster.
• Insulated curing blankets, and for some commercial work, heated enclosures.
• Watching the forecast for overnight lows, not just the daytime high.

Hot-weather pours

July heat and wind pull water out of the surface fast, which can cause plastic shrinkage cracks and make finishing a scramble. We schedule hot-weather pours early in the morning, dampen the subgrade so it does not soak up mix water, and apply curing compound or keep the slab moist once it is finished.

Rain

A soaking rain the day before can soften the subgrade, and rain on a freshly finished surface can wash out the paste and leave it pitted. We would rather move a pour a day than put down a surface that will not last. Once concrete has set, light rain actually helps it cure.

What this means for scheduling

Spring and early summer fill up fast. If you want a driveway or patio done before a summer event, call in the winter or early spring to get on the calendar. Site work, excavation and some foundation work can often continue later in the year than finish flatwork can.