How to Keep Frost Heaves From Lifting a Concrete Driveway

Call 811 for information on the location of underground utilities in your yard. Contact the local building department to find out the depth of the frost line in your area. Digging the foundation below the frost line is the first step in preventing a frost heave.

Dig out the site with a shovel until it is at least a foot deep. Dig out an extra inch more every 8 feet so the driveway slopes down to direct underground moisture into the street. Go over the subsoil several times with a compactor to push out air pockets and excess moisture.

Lay down two 4-inch deep layers of 3/4-inch gravel. Compact the rocks after each layer. The irregular size and shape of the rocks will compact into a strong base while leaving space for moisture to drain away. They also provide enough flexibility to absorb tension and prevent a frost heave.

Position 2-by-6 inch boards around the site and screw them together with a drill and screws.

Place steel mesh on top of the gravel to reinforce the slab. Lay steel rebar on top of the mesh 1 foot from the sides and through the center. Set the lengths on rebar chairs so they run through the center of the driveway slab. The steel strengthens the concrete, making it less vulnerable to a frost heave.

Pour a 6-inch thick layer of concrete over the steel and gravel base. Screed the surface by pushing a long board over the top and smooth out the wet concrete with a trowel.

Cut control joints into the surface after it sets for an hour. Run the end of the trowel through the concrete in a grid every 3 square feet. The joints must be half the depth of the slab. Once hardened, they will prevent water from seeping through the surface by providing a path for it to escape.

Seal the slab, once it has cured for a week, with penetrating sealer applied with a roll brush. Filling the porous surface strengthens it and repels water so it won't get trapped below the surface.