Abstract: A wall system utilizing a plurality of precast concrete panels so that a parallel inside wall and outside wall is created. Each panel of the plurality has a continuous slot on all four perimeter sides that mutually oppose slots on adjacent panels. A strip fits into the slot formed by the two abutting panels, thus aligning, reinforcing, and sealing the plurality. The outside wall is connected to the inside wall by one or more embedded protrusions from said opposite panels so that said protrusions overlap upon each other. The overlap is then fastened together by a chosen method, for example a bolt and nut which may include washers or spot welding areas of intersection yielding a rigid bridge between the opposite panels.