How to Build Steps Into a Hillside

Measure the rise and run of the hillside where you'll be building the steps. Divide the hillside's rise in inches by six to determine the number of steps you will need. Round the result to the nearest whole number. Divide the run in inches by the number of steps to determine the size of the treads. Ideally, your treads will be between 13 and 15 inches wide. Purchase pressure treated lumber with the height of the determined rise and at least 4 inches wide.

Drive one stake in each of the corners of the stairway. Run string tightly from one stake to another to create the outline of the path of steps and to act as a guideline.

Dig a shallow trench at the bottom of the stairs for the first riser. The trench should be just deep and wide enough in order for the pressure-treated lumber to be able to sit securely in the ground. Dig trenches for the first riser's side timbers to 6 inches past the tread depth. The trenches will get deeper as you dig into the hillside. Ensure that the bottoms of the trenches remain level.

Measure and cut the front and side risers to length. The side risers should be the length of the tread, plus 6 inches, minus the width of the front riser. Bore a 1/2-inch hole on each end of each riser, centered 2 1/2 inches from the ends. Place the risers in the trenches and level them with additional soil as needed. Drive an 18-inch length of rebar through each of the predrilled holes and into the ground to anchor the step. Dig out the soil between the timbers to create a level surface between the sides of the step.

Cut the front riser to the same length as the first stair for the second step and drill a pilot hole centered 2 1/2 inches from each end. Place the front face of the second riser 6 inches from the ends of the side risers below, lining up the drilled holes. Drive a 12-inch galvanized spike through each of the predrilled holes to anchor the new step to the one below.

Dig a shallow trench for each of the second step's side risers level with the tops of the first step's sides. Measure and cut the side risers to the same length as those for the first step. On the end of each side riser that will overlap those of the first step, drill a pilot hole. Position the side risers, level, and drive a 12-inch galvanized spike through the pilot holes into the risers below. Dig out the soil between the timbers to create a level surface between the sides of the step, as before.

Repeat Steps 5 and 6 for the remaining steps. Cut the side risers for the top step 6 inches shorter than the ones below. Measure and cut lumber for a back riser for the top step. The riser should fit between the two side risers. Anchor the riser with 18-inch rebar as in Step 4. Remove the stakes and string guidelines.

Pour and tamp down gravel in the trench between each step to create a two-inch bed. Pour and tamp down sand over the gravel until you reach a height where the brick or stone of your choice lies flush with the top edges of the risers. Level the sand.

Arrange bricks or stones in the sand, leaving 1/16-inch to 1/8-inch joints between each piece. Tap the bricks into place and level as needed. Spread a thin layer of mason's sand over the bricks. Sweep the sand in all directions to fill in every crack. Spray the surface lightly with water to wash off extra sand from the surface and to pack the sand. Allow the sand to dry. Sand and spray as needed until the joints between the bricks are all filled and compacted.