A system is provided for retaining a flowable and curable building material to form a portion of a foundation of a structure of interest. A first and second side wall receive and retain the building material in a channel bound by the side walls. At least one of the side walls defines an interior cavity. A venting conduit is disposed within the structure of interest and coupled to the interior cavity to form a first passage. A bracket assembly retains the side walls in the predetermined configuration and includes two or more reinforcement posts and a separator bar. The separator bar has a first and second set of apertures proximate a first and second end that are sized to receive and retain a pair of the reinforcement posts at locations to establish a width of the components of the side walls and the channel being formed therebetween.