Overlaying Concrete for Freezing Temperatures

Additives and Air Bubbles

• Concrete does not react well with freezing weather, mostly because moisture often seeps into the concrete, expands as it freezes and creates small cracks that eventually deteriorate the concrete surface. Overlays already should have polymer additives that make them more flexible, but you might also be able to mix additives that create air bubbles in the concrete. This actually makes the surface stronger and less likely to crack under freezing.

Curing Compounds

• Concrete must cure properly. Overlays should have low water content to prevent later freezing issues but need the right amount of water while they cure. The solution is curing compounds that you can spray over the surface when you are finished installing it. These compounds prevent water from escaping through evaporation and ensure that the surface dries properly.

Slopes

• When creating your overlay for driveways and sidewalks, remember to slop them properly. Concrete slabs should always be sloped toward the edges so that water can easily flow down into the soil instead of resting on the top of the concrete itself. Any amount of pooling moisture, even if you can't see it, can freeze and cause problems. So level your overlay, but also remember to slope it correctly.

Sealants

• When your overlay finishes curing you will need to seal it to create further protection. Choose a sealant that is designed for concrete in harsh weather conditions and follow the instructions exactly. Wait to put a sealant on until the first stage of curing is complete, which can take up to several days.