a residential or light industrial cast - in - place building foundation system including a form insert made of polymer foam , wood or plastic meant to stand upright within a typical removable concrete form side by side with poured concrete . once assembled for use , a series of channels and voids are formed on one side of the normally flat removable forms . each channel is designed to flare toward the outside of the concrete form to transfer energy and pressure through the concrete to be placed within the forms . after the concrete cures and the form panels will be removed , the form insert can be left in place for thermal efficiency or remove and reused on another project .