How to Use Joist Materials to Form Stem Walls

Prep

• 1

  Mark the dimensions of the footing for your stem wall. Use a wood stake at each corner and tie string between them to create the outline. Drive your stakes in with a hammer. Dig your footings out to the correct depth, using a spade. Keep the sides and corners as square as possible.

• 2

  Divide the height of your wall by the width of your joist materials. If your joists are 2 inches by 6 inches, each board is 5 1/2 inches wide. If your joists are 2 inches by 8 inches, the boards will be 7 1/2 inches wide. Cut enough boards to the correct length for your wall to cover the required height. Use a circular saw to make the cuts.

• 3

  Drive in wooden stakes about 6 inches back from the edge of the footing, every 24 inches along the length of the footing.

Assembly

• 4

  Layout the side walls of the form on the ground, with the pieces butted up to each other in rows. Cut pieces of 1x2 to the height of the form, one for every 12 inches of length. Position the pieces on top of the joists, running perpendicular to the joists, from top to bottom of the wall. Drive 1 15/8 inches treated deck screws through the 1x2 using a cordless drill, two screws in each joist where they intersect.

• 5

  Stand up the side walls with the 1x2s to the outside and cut pieces of 1x2 to angle from the top of the wall back to the stakes behind. Attach the 1x2 pieces to the stakes by nailing them with box nails. Use a level to ensure the wall is vertically upright and nail through the 1x2s into the top edge of the form wall to hold them in place.

• 6

  Cut pieces of joist to fit from outside to outside of the ends of your form. Cut as many pieces as you used in the height of the walls. Attach them at the ends to box in the form, using 3-inch, treated, deck screws, two screws through each piece into the end of each joist in the walls.

• 7

  Pour your concrete into the form, laying in rebar at required intervals in the depth of the wall. This will be determined by local building codes. Lay the rebar in lengthwise along the entire length of the wall, at least one row of rebar for every 12 inches of height. Pour the concrete to the top of the form, then level it off with a float.