How to Create a Footing

Excavate the site where the structure will be built to 1 foot under the frost line (if present at your location). Mark off the center lines where the walls will eventually be. This center line will also be the center line of the footing.

Determine the thickness your foundation walls will be and double it to get the width of your footing, with the depth being at least the same thickness as the wall. One industry standard is to build your footings so they are 30 inches wide and 10 inches deep.

Build the footing form work. Cut your plywood sheets into strips at least 12 inches wide and hold them in place using stakes made from 2-by-4s hammered into the soil, or use purpose-built foundation stakes. Ensure corners are square and that the center line laid out earlier is in the center of the footing framework.

Lay rebar rods into the frame, resting on sections of 2-by-4s so they will be completely submerged when the concrete is poured. There should be at least two rods side by side throughout the entire framework. If any drain work needs to be routed through the footing, this should be done now. Any footings for columns, chimneys or other load bearing appendages should be made now as well.

Pour the concrete directly into the footing framework onto the excavated soil floor -- held in place by the plywood form work. Pour to a level of determined depth or roughly 10 inches. Use a scrap piece of 2-by-4 plank to smooth the top of the footing, then lay lengths of 2-by-4s along the center line of the footing, pressed into the top of the concrete to create the key the foundation walls will lock into later. Also press in vertical sections of rebar along the center line to aid in adhering the walls to the footing.

Allow appropriate time for curing. Remove the framework and backfill with gravel before erecting the framework for the foundation walls.