Abstract: A method of constructing a building includes erecting a wall panel extending vertically. A hollow post form attaches to one side of the wall panel, and an insulation panel is placed adjacent to the inner wall panel. The method includes attaching an outer wall panel to the hollow post form on a side opposite the inner wall. The panels are sandwiched together by connecting the panels with a fastener that extends through all of the panels. The hollow post form is filled with a structural binder such as concrete. A ceiling structure is attached to the wall structure and includes layered panels. The ceiling structure defines a floor beam void and, along with the wall structure, defines a tie beam void. The hollow posts and the beam voids are filled with a structural binder such as concrete after the walls and ceiling are constructed.