We live in a more tolerant society, but any experienced concrete contractor will tell you the opposite about the construction business. No building is ever built perfectly, yet contractors (and often, their invoices) are held to theoretical tolerances that are too tough and expensive to meet under real-world conditions. Is it time to consider relaxing design standards to help save money on rework, lost time and litigation?
Veteran industry authors Bruce Suprenant and Ward Malisch think so. The two concrete experts have spent decades helping builders overcome such problems as out-of-plumb doorways and curtain walls that cannot seem to square up because their specifications conflict with each other.
By measuring as-built tolerances over the years and comparing them with what was called for, the authors expose good and bad standards and suggest ways to make the onerous ones reasonable in “Tolerances for Cast-in-Place Concrete Buildings” (American Society of Concrete Contractors, 2009, $70).
Contractors “want to successfully build a project and get paid in a timely manner,” the authors say. That goal, however, is increasingly more difficult to achieve because the concrete contractor often is “held hostage” and forced to resolve tolerances that may not need to be met in the first place for the structure to perform safely and effectively.
Attention should be paid to relaxing tolerances so they are based on field data, measured in set procedures and written so they cannot be misunderstood, the authors advise. “Until there is one consistent set of interpretations…contractors cannot determine how to improve,” the book says.