Pour the footers before pouring the walls.
A home's foundation may be a basement, a crawl space or just a slab-on-grade. Before the contractor forms and pours the foundation, he will pour the footers to reduce future foundation movement due to soil shifting or settling. Poured directly onto the ground, the footers serve as the base that will support the rest of the foundation.
Instructions
1. Excavate the footer trenches. The standard footer is 1 foot deep and 2 feet wide and it is directly beneath the foundation wall. In addition, footers must be below frost line to prevent foundation shifting that may occur when the soil swells and contracts from temperature changes. Your local codes will tell you how deep you must pour footers.
2. Add steel reinforcement to your footer trenches. Although building code determines the amount of steel reinforcement in the footers, a standard practice is to install three rebar rods, running parallel to each other, approximately 6 inches apart. Additionally,18-inch rebar rods, placed at 3-foot intervals, cross the longer rods.
3. Secure the long rebar rods to the shorter rods that cross at right angles with rebar ties. Place one tie beneath each "T" where the rods intersect, and bring it up on both sides, twisting it together tightly. Repeat with every intersection.
4. Raise the rebar off the ground with rebar chairs. These small plastic units have indentations in the tops to hold the bars. Rebar chairs raise the level of the rods a couple of inches off the ground, allowing the wet concrete to fill in around the rebar.
5. Pour the concrete and level the footers. Unlike concrete walls, footers rarely have exterior forms so the concrete truck dumps the wet concrete into the trenches and the workers spread it out from side to side with shovels, leveling it as they go with large hand trowels.
6. Insert the vertical rebar for the future basement walls or stem walls before the wet concrete sets. As soon as the concrete thickens enough to support the rods, drive each one in, by hand, near the center of the footer. The exact placement is not vital as long as the rods are within a couple inches of the center on either side. Local code may regulate the distance between rods but a standard distance is 3 feet apart.
