Design-build is a very old method that fell out of use until recent years. It is derived from what used to be called “turn-key” construction.
Under this approach, the municipality selects one contractor to both design and build the project. The basic principle of the design-build methodology is to place full or partial responsibility for both design and construction on the designer-builder. The latter is often a construction contractor who has teamed with a design firm. Alternatively, some of the larger design firms formed construction departments that specialize in the design-build approach.
According to the Design-Build Institute of America, the design-build form of project delivery is a system of contracting under which one entity undertakes to perform both architectural/engineering and construction.
The design-builder warrants to the contracting agency that it will produce design documents that are complete and free from error (the design-builder takes the risk). The selection process under design-build contracting can be in the form of a negotiated process involving one or more contracts or a competitive process based on some combination of price, duration and proposed qualifications.
Portions of the overall design or construction work can be performed by the design-build entity or subcontracted out to other companies that may or may not be part of the design-build team. One goal of the design-build approach is to save time.
Since the designers and builders work together from the beginning, the design effort can be substantially reduced. It is not necessary to prepare drawings in great detail if the builder already understands what needs to be done.
Time may be saved by using a fast-track schedule under which the builder begins working on each phase of the construction as soon as the design for that phase is complete.
Ideally the designers complete the next phase just as the builder is ready to start that phase. Design-build works very well when using standard designs that have been built repeatedly.
For instance, everyone knows what a gas station should look like. In much the same way, it is absolutely critical the municipality and builder have the same clear picture of the final project before construction begins. Unfortunately, many types of municipal public buildings are not of the cookie-cutter type design typical of a gas station.
The design-build approach requires the municipality to evaluate firms based on a plan and its presentation. However, any such plan has an inherent preliminary character. There is a risk of cost inflation during the transition from preliminary design to final design (and design approval).
Once a contract has been awarded based on evaluation of a plan, there is a risk the plan may include unattainable ends with the result it becomes in the contractor’s interest to follow through on everything in the plan.
No matter how carefully one crafts the evaluation criteria, the number of points awarded by members of the evaluation team is usually arrived at subjectively. The award of the contract on the basis of an overall “best value” compromises the competitive nature of the bidding process.
Since design-build contracts are usually awarded on the basis of preliminary plans, the design-build contractor has substantial control over what features will be incorporated into the buildings.
The process of finalizing the plan often leads to sacrificing the municipality’s interest. Often changes are incorporated into the final design that should have been incorporated under the “best practices” standard of the engineer or architect design professional.
Such features do not add value to the final buildings. Similarly, the design finalization process often results in changes being approved that enhance the profitability of the contract for the design-build contractor but simply deprive the municipality of the value that it hoped to obtain.
Such changes should be approved only where they were not implicit in the municipality’s original specifications.
