How to Build a Cement Retaining Wall

You may need to build a retaining wall to keep the beach where it belongs or you have a low backyard that tends to flood when the nearby river get a bit high. You may even just want a wall separating a portion of the outdoor living area from the rest of the back yard. Whatever you need a retaining wall for, you can build it yourself.

Difficulty: Moderate

Instructions

Things You'll Need:

• 3/4" Plywood
• 2"x4" Lumber
• Rebar strips
• Cement
• Shovel or trencher
• Nails
• Motor oil
• Paint roller or paint brush

1. Prepare the area where the wall will be constructed by digging a trench the length of the wall. Make the trench width the width of the finished wall plus at least six inches on each side to allow room to work. Make sure to go at least 12 inches below grade on the downhill side of the area.

2. Build the form. Before you can being to build your cement retaining wall you must construct the form. The form is the mold where the cement will be poured to form the wall. The form should be built with the inside measurements matching the final size of the wall. Using the height plus ¾” x 2, calculate how many sheets of plywood you’ll need to create the form. It’s a good idea to coat the plywood with motor oil before you cut it. The motor oil makes the plywood easier to remove once the wall is constructed and cured. Cut ¾” plywood into sections ¾” higher than the height of the wall above ground. Nail 2”x4” studs the width of the wall to the plywood. The studs should be placed every 24 inches along the length of your wall. These are the interior spreaders. Now it is time to place the form. Set both sides in place, making sure each is level and plumb. Brace on the outside of each form wall with stakes, making sure to keep the form in place as you drive the stakes.

3. Place the rebar. To provide additional strength, you will need to add lengths of rebar. Every 18 inches, drive the rebar into the ground. If you’re planning to cap with cement, make sure the rebar sticks up an inch or so above the bottom edge of your spreaders.

4. Pour the cement. Once the form and rebar are in place you’re ready to pour the cement. Depending on the size of the wall, you can either mix the cement yourself or order it already mixed. As you are pouring the concrete, it must be tamped to make sure all the air bubbles are out. You can buy a tamp or construct one from a 2x4 and plywood. Hit along the top of the cement with the tamp to force out any air within the poured cement. Once the cement has partially set use a float to smooth out the top surface.

5. Remove the forms and finish up. Before the forms are removed, the cement must cure. Curing is the natural process of the cement drying. Once it has sufficiently cured, you can remove the forms. Aesthetically you can cap the wall with brick, wood or precast cement. Add perforated pipe for drainage. Once the drainage pipes are in place, backfill to create the desired effect on the landscape.