How to Build Concrete Footers for a Garage

Concrete footers serve the single most important aspect of any building project: holding and supporting the walls and floors. Small and poorly built footers will cause the walls and floors of your project to sag and crack and sometimes collapse. Using tried and proven methods to build sufficient footers will save you time and heartache in the end.

Things You'll Need

• Shovel
• Pick
• Tape measure
• Level
• Rebar
• Concrete

Instructions

1. 

   Dig your footers.

   Dig the footers at least twice the thickness of the foundation walls for your garage. For example, if your walls are 8 inches thick, dig the footer trench 16 inches wide. Square the trench on all four sides and 12 to 16 inches deep. The dept of the footer is important to ensure the weight of the garage walls will not collapse the footer. Level the footer trench with a builders level or a 4-foot hand level.

2. 

   Use rebar for strength.

   Lay two lengths of 1/2-inch rebar along the entire length of the footers. Set the rebar on rebar chairs so the rebar is two to four inches off of the ground. Tie the rebar together using rebar ties. Place 16-inch cross bars 24 inches apart along the rebar. Tie the rebar at all corners and at the rebar chairs to prevent the rebar from falling of the chairs.

3. Drive 16-inch rebar into the ground between the horizontal rebar that has been laid for reinforcement. Space the rebar 48 inches apart. Drive the first one in at any corner leaving 12 inches aboveground. Use a level to check and drive the remaining rebar into the ground. These rebar will be grade stakes for your concrete height. You will pour concrete to the top of these rebar pins.

4. Clean out all dirt debris that has fallen into the footer ditch in the process of setting and tying the reinforcing horizontal rebar. Use a small mason's trowel to reach between the rebar on the rebar chairs and scoop away the extra dirt that may have fallen into the footer ditch. Paint the top of the vertical rebar grade pins that you drove into the ground. This will help you find them while you are pouring the concrete.

5. 

   Pour concrete to build footings.

   Pour 3,000 psi concrete into the footers and rake the concrete around in the footer until the concrete height is to the top of the rebar grade pins. Smooth the concrete with a concrete trowel. Allow the concrete to cure for 48 hours before placing foundation walls on top of the concrete.

References

• "The Black & Decker Complete Guide to Home Masonry: Step-by-Step;" Editors of Creative Publishing; 2000