How to Build Concrete Form Stairs

Measure the distance between the ground and the top of the landing area or doorway to calculate the height of each riser. Divide the distance by any measurement between 8 and 10 inches for a standard riser height. The result will be the number of risers required.

Measure the distance between the ground and the top of the landing area or doorway to determine the width for each tread. Divide the distance by 15 inches or more for a standard tread depth. The result will be the depth of the treads required.

Remove the soil in the planned area 6 inches deep with a shovel. Use a rake to level the soil. Place a level on the soil to be sure the soil is close to level. Create a sound base with a hand compactor.

Add 2 inches of gravel and compact with the hand compactor. Add 2 more inches of gravel and compact well to the first layer. Place a level on the compacted gravel and add or remove gravel until the entire compacted gravel surface is level.

Place two long stakes in the back of the stairs with the top of each at least 1 foot higher than the top of the planned top riser. Place two stakes at the front of the planned stairs with the top of each at least 3 inches higher than the planned bottom riser. Place stakes for each additional riser at the corner of each riser on the outside edge with the top at least 3 inches higher than the planned top of each riser. Use a level to plumb each stake on all sides.

Cut boards to the width of the planned riser height with a hand or circular saw. Cut the boards to the length for the bottom stair from the back of the stairs to the front of the stair. Cut another board to the width of the stairs. Attach each to the inside of the stakes with screws for the bottom stair form a box that extends from the front of the stairs to the back of the stairs. Place a level on each after installing the first screw and adjust so the top of each board is level and at the same height as the other two boards. Install a few stakes tight to the board at the front of the box to keep it from bowing out when the form is filled with concrete.

Create the next level by creating another box. Cut the boards to the width of the planned riser height with a hand or circular saw. Cut the boards to the length for the second riser from the back of the stairs to the front of the stairs. Attach to the stakes for the second step and check with a level. Repeat for each additional riser. The final form resembles a series of smaller and smaller boxes stacked on top of each other.

Fill the center of the bottom stair with broken concrete, rocks or gravel to reduce the amount of concrete needed to fill the cavity. Leave enough room for at least 4 inches of concrete around the filler material.

Mix enough concrete to fill the first box in a wheelbarrow according to package directions. Pour the concrete into the first box until it is level with the form. Use a concrete float to smooth the top of the concrete for the step and a concrete edger to smooth the edges by placing the edger between the form and concrete. Wait an hour and mix enough concrete for the second riser. Pour the concrete into the box for the second riser and smooth with a concrete float and a concrete edger to smooth the edges by placing the edger between the form and concrete. Repeat for each additional level. Allow the concrete to set for 24 hours before removing the form.