If you are pouring a new concrete walkway for your home, you want to make sure you take measures to prevent frost heaving, which happens when ice forms on the bottom of the concrete, expands and causes the walkway to push upward and crack. To prevent this eyesore and potential fall hazard, use the tips below to properly prepare the base of your walkway.
Place A Thick Sheet Of Styrofoam Insulation Directly Inside The Trench
After you have dug the trench into which you will pour the concrete for your walkway, place a thick sheet of styrofoam insulation directly inside. The insulation serves as a barrier between the ground and the walkway, helping to keep the cold moisture from the dirt from siphoning up and attaching itself to the concrete.
Before laying the styrofoam, tamp down the dirt with the end of a two-by-four board until it is as smooth and level as you can get it. Then, cut the insulation to snugly fit against both sides of the trenches and place it inside. Gently push the styrofoam until it is flush with the dirt.
Lay A Single Layer Of Gravel On Top Of The Styrofoam
Even with the styrofoam insulation, you may still have some water seep in between the concrete and the styrofoam. If there are no gaps between the two, the frozen water will have no room to expand and will push up into your walking, resulting in frost heaving. Because of this, place a single layer of gravel on top of the styrofoam.
The gravel provides a rough area with which the concrete can bind. Even when poured smoothly, there will still be small gaps beneath the gravel. These gaps serve as stable channels through which the water can flow. When the weather turns cold, any water trapped in those spaces may still freeze, but the gravel and styrofoam beneath it should absorb most of the impact of the expansion.
When placing the gravel layer, make sure you use only one layer by smoothing it out with the flat side of a yard rake. Having multiple layers can compromise the integrity of the walkway, causing it to break apart at the base and allowing water to directly impact the concrete.
Using the tips above should help you prepare your walkway's base to minimize the possibility of frost heaving during the winter. However, if you want to make sure all the proper precautions and steps are taken, you may want to speak with a concrete paving contractor about any questions and to discuss any options available.