It is generally recognized and accepted fact that the steel industry frequently underwrites the cost of structural steel designs to try to achieve an over all cost advantage over reinforced concrete construction. It would seem only logical, therefore, to assume that the steel industry is aware that reinforced concrete frequently has a cost advantage over structural steel. Nobody expects any blanket admissions on this subject from the steel industry, but there is an abundance of supportive evidence in the form of case histories. Rebar availability can often be an important factor in determining cost. But what if Number 3 isn't available, as often happens? A good option is to increase slab thickness to 6 and one-half inches, open up column spacing and use Number 4 bars at 13 inches as the base mat. This not only results in better utilization of steel but also gives the architect some increased flexibility. It is now possible to paint right over as-cast interior concrete surfaces without applying drywall. Some extra care may be called for in concrete forming, placing, and vibrating to achieve a suitable finish, but the saving in gypsum wallboard and labor is significant and wholly attributable to the concrete frame. Interior concrete wall and ceiling surfaces are being painted with good results even in luxury apartment buildings, giving reinforced concrete construction still another cost advantage. Tolerances are an important factor in determining the ultimate cost of a concrete structure. Costs inevitably rise as tolerances are tightened, so a good rule to follow is not to demand unnecessarily close tolerances. Specified tolerances should always be a function of the adjacent or surrounding elements, including precast concrete, whose placing may depend in large measure on the accuracy of the concrete work.