How to Pour Concrete Footings for Retaining Walls

Retaining walls are used to prevent elevated soil areas such as hills and inclines from creeping into lower areas. This type of wall is almost always made from masonry building materials such as concrete. While a retaining wall is a solid structure, it would be useless without footings, which act as anchors in the ground beneath the wall. Concrete footings are poured in place and designed to use the combined strength of concrete and steel rebar. Pouring concrete footings is usually a simple task, depending on their design and complexity.

Things You'll Need

• Concrete
• Cement mixer
• Tape measure
• Inverted marking paint
• Building plans (foundation plan)
• Wood planks for forms (size depends on footing size)
• Screw gun and 1-inch screws
• Circular saw (wood and abrasive blades)
• Wheelbarrow
• Steel rebar
• Rebar ties
• Shovel
• Pick axe

Instructions

1. Measure and mark the footings using a tape measure and marking paint. Refer to the foundation plan for footing locations, depths and widths.

2. Dig the footing to the depth and width specified in the foundation plan, using a shovel and, if necessary, a pick axe.

3. Drive the wood stakes into the dug footings, spacing the stakes at the width of the footing plus the thickness of the wood forms. (For example, for an 18-inch-wide footing, the stakes should be at least 18 inches apart plus the thickness of the forms, which usually will be an additional 3 inches.) Attach wood planks (forms) using screws. The forms should be screwed to the footing side of the wood stake, and their size should correspond to the footing height. Cut the wood forms to length as needed, using the circular saw.

4. Lay the reinforcing rebar in the footing according to the foundation specifications. The amount and layout will vary depending on the wall; refer to the sections or details sheet for rebar spacing and location specifications. Cut the rebar to fit as needed, using the circular saw with an abrasive blade.

5. Mix the concrete in the cement mixer according to the concrete package's mixing instructions. Refer to the operations and safety manual of the cement mixer before using.

6. Pour the concrete from the mixer into the wheelbarrow, then carefully pour the concrete from the wheelbarrow into the space between the wood forms, starting at one end of the footing and working your way to the other. This will take several trips. You can also use a shovel to spread the concrete throughout the footing.

Tips & Warnings

• Retaining walls should be designed by a structural engineer to ensure maximum strength.

• Don't spend too much time trying to install perfectly straight wood forms. Small imperfections will not affect the structural integrity of the footing.

• Always wear safety glasses when cutting steel rebar with a circular saw, because metal flakes can cause severe damage to your eyes.

References

• Working with Concrete; Rick Arnold; 2003
• Fundamentals of Building Construction: Materials and Methods; Edward Allen and Joseph Iano; 2008