DIY Foam Insulated Footings

Excavate the area where the foundation of the house will be placed. Rent a 1 1/2-ton excavator or hire a contractor to do it.

Dig a trench for the footings around the outer edges of the foundation site. Dig the trench deep enough to extend beneath the frost line. This depth can vary, from a few inches in the southern United States to several feet in the northern U.S. Make the trench at least twice as wide as the walls of the foundation, plus an extra foot so you have room to place the forms for the footings.

Construct the framing for the footings by driving wooden stakes into the ground every 3 feet on both sides of the trench and 1 foot away from the trench walls. Place 2-by-4 boards along the ground inside the stakes, standing them on edge, and nail them to the stakes. Lay a second course of 2-by-4s on top of the first course. These boards are the sides for the forms.

Cut strips of foam insulation boards to fit along the inner edges of the footer forms with a utility knife. Place them inside the forms.

Place 1-by-4 boards across the forms every 3 feet and nail them to the 2-by-4 boards and into the top edge of the foam boards to lock them into place. The 1-by-4s provide extra structural support to the forms while the concrete is being poured.

Pour concrete into the footing forms and smooth the surface of the concrete with a 2-by-4 board. For a project of this size, you'll want to hire a concrete supplier that can produce the amount of concrete you need.

Remove the forms after the concrete has cured for at least four to five days.