Because total precast concrete systems allow the architectural panels to serve structural functions, this limits the need to incorporate multiple materials and trades. Cost benefits include shifting up to 75% of the labor and related risk from the jobsite to a quality-controlled precast concrete plant environment. Reduced detailing and complexities such as spandrel panels can support floor systems and windows while providing final exterior finishes or sill panels that can be used as grade beams to retain soil, support windows, provide the architectural exterior finish, and help avoid complex cladding systems. Combining exterior spandrels into the structural system also provides deeper elements, limiting deflections and the complexities of designing for relative movements between frame and cladding systems.