When building components won't fit because of dimensional variations in cast-in-place concrete, concrete products, and other materials, someone has to pay for correcting the interferences. Concrete constructors and material fabricators will probably have to pay if their products are not within specified tolerances. If all materials are within specified tolerances but the variations still cause an interference, the architect or engineer may have to pay for the correction. Ambiguous situations or situations not covered by specified tolerances may become a free-for-all of claims and counterclaims.

This article briefly describes five projects that illustrate these ideas and provide illuminating lessons. The architect or engineer must specify details that account for tolerances. The contractor must build to meet the specified tolerances. Wise contractors try to anticipate problems even when their work meets specifications. If a project requires tolerances that are tighter than the industry standard as represented by ACI 117, then the owner must be willing to pay a substantially higher price for concrete construction.