Concrete itself does not mind the cold. Water does. Every crack and open joint is a place for rain and melt to sit, and once the temperature drops, that water expands as it freezes and pushes the concrete apart from the inside.
Run that cycle a few dozen times over a Dayton winter and a hairline crack becomes a real one, and a slightly low panel becomes a trip hazard by spring.
A fall checklist
- Reseal joints and cracks before the first hard freeze, while the concrete is still dry enough for sealant to bond.
- Redirect downspouts and splash blocks so they empty well away from slabs and the foundation.
- Clear leaves and debris out of joints; a clogged joint holds water instead of draining it.
- Skip rock salt on new or repaired concrete; use sand or a calcium-based melt instead.
That last one matters more than most people think. Rock salt lowers the freezing point of the water sitting on the surface, but the freeze-thaw cycling it causes right at the top of the slab scales and pits the finish over a few winters, especially on concrete poured or patched in the last year or two.
If a panel is already a little low, winter is when it shows: water collects in the low spot, freezes, and the next thaw drops it a little further. Getting it lifted before the ground freezes solid is easier on the crew and cheaper for the job than waiting for spring.