Thousands of examples of breathtaking architectural concrete structures prove that beyond providing strength, durability, sustainability, and economy, concrete can be a versatile medium of artistic expression. Achieving such art requires that the contractor orchestrate the right combination of formwork, materials, techniques, and timing, and does so uniformly throughout the architectural phases of the project.
But before even the most experienced contractor plans, estimates the cost, and executes an architectural masterpiece, the expectations of the architect and the owner must be absolutely clear. The contractor must know what it will take to make the owner happy on an architectural concrete project or be prepared for failure. Remember this rule: If the owner ain’t happy, ain’t nobody happy.
ACI defines architectural concrete as “concrete that will be permanently exposed to view and therefore requires special care in selection of the concrete materials, forming, placing, and finishing to obtain the desired architectural appearance.” In addition to any of the routine, yet critical, requirements for fresh and hardened concrete, such as slump, air, strength, temperature, and tolerances, acceptance of, and full payment for the finished product will depend on appearance as judged by someone’s eye. Measureable, numerical values are routinely obtained for strength and potential durability of concrete, and these values are then compared with specified criteria to judge acceptability. Those same kinds of objective measurements are not typically available to judge the appearance of hardened concrete, and that can make the question of contract compliance a judgment call.
The challenge for contractors is to divine the owner’s and architect’s genuine intent before establishing the bid price. Unfortunately, in some cases, the genuine intent only becomes clear when the contractor’s first efforts are declared unacceptable. The challenge for the specifier is to prepare bid documents that unambiguously define the required, yet subjective, qualities of color, tone, texture, and uniformity (or variability) of the concrete.
Where the challenge begins
Architectural concrete begins in the imagination of the owner. If the finished structure looks and feels like what the owner had imagined from the beginning, there is joy on the project and the retainer is paid. Getting to that blissful state requires first and foremost that the architect capture the owner’s dream and translate it into executable contract documents.
In reality, the contractor provides a finished structure that must be an acceptably close approximation of what is described in the contract documents—the design team’s challenge is to produce plans and specs that define what is an acceptably close approximation of what the owner wants. To satisfy the owner, therefore, requires that the contractor’s approximation of the designer’s approximation is close enough to the owner’s dream.
Skillful architects use artistic renderings, models, computer simulations, samples, mockups, and visits to existing structures to refine and confirm the owner’s desires. But despite these lengthy and expensive efforts, some owners can’t visualize the finished product until it’s finished. And despite the fact that the work may be in substantial conformance with the plans and specs, the owner might still say, “That’s not what I had in mind.”