Abstract: An apparatus and method for constructing pre-insulated structural panels is disclosed that has a tongue and groove assembly arrangement. Each panel may include one or more c-channels or profiles embedded in expandable polystyrene (EPS) foam to provide structural integrity to the panels, and resulting wall. The panels may be covered with siding, stucco, or similar materials. A chase may be formed horizontally in the panels to provide a wiring conduit through the panel. The panel may also provide when assembled, a vertical chase formed between the mated panels along the length of the panel for wiring. Acoustical properties may be formed in the surface of the EPS portions to provided added acoustical damping measures.