Preformed concrete steps allow builders to install steps without creating precision molds. Preformed concrete steps are poured in a temperature- and moisture-controlled environment which makes them less susceptible to cracking due to moisture trapped in the concrete. To install preformed concrete steps, you need a stable foundation that will not move when the ground freezes.
Measure the footprint of the steps with a tape measure and then transfer the measurements to the ground in front of the steps. Mark each corner with a wooden stake and connect the stakes with a string. This gives you an accurate outline of the ground you need to work with.
Excavate the area inside the string to the frost line. The frost line differs depending on where you live. Refer to the frost line map (see Resources below) for the frost line in your area.
Level the ground in the hole with a rake and tamp the ground with a tamper to create a solid surface.
Fill the hole with crushed gravel to within four inches of the top of the ground. Tamp the crushed gravel with the tamper to create a level surface.
Fill the gravel with sand to further pack in the area below the steps and to create a stable surface. Stop when the sand remains level with the crushed gravel.
Pour a four-inch slab of concrete into the hole until the hole is level with the ground and wait at least 72 hours for the slab to cure.
Place the concrete steps on top of the slab and butt the steps against the building.