For more then twenty years I have been involved with various forms of D-B and I really enjoy the process. Unlike design-bid-build (DBB), better known at "plan and spec" and construction management (CM), the DB team can truly provide single-source responsibility. Certainly DBB doesn't provide this sense of ownership. In fact, DBB promotes an adversarial environment between the designer and the builder and here is why:
  • Design team complete the conceptual phase with no contractor participation.
  • Design team complete the schematic phase with no contractor participation.
  • Design team complete the design development phase with no contractor participation.
  • Design team complete the construction document phase with no contractor participation.
  • Design team architect completes the bid period with little contractor participation.
  • General contractor facilitates the construction phase with limited participation by the design team.
  • General contractor facilitates the project closeout with little participation by the design team.
  • In the warranty phase there is little to no participation by the design team or the general contractor unless there are project problems, and at that point in time, the design team and the construction team will probably have different points of view as to the solutions to the problems

CM can be a more rewarding job for the construction manager because they can control the project, something the designer can't do or the individual trade contractors. If the job goes well, the construction manager can lay claim to a job well done. If the job doesn't go well, this manager is in the position to save the job and, if needed, assign the blame to the design team or the trades. Single-source solutions don't occur with the CM process because:
  • Design team complete the conceptual phase, schematic phase, and design development phase while the CM may provide construction project pricing.
  • Design team complete the construction document phase while the CM provides a GMP (guaranteed maximum price), which will not be as low as an equivalent DBB project and not necessarily the optimum price for the job.
  • CM facilitates the bid period with limited participation by the design team.
  • CM facilitates the construction phase and project closeout with limited participation by the design team.
  • In the warranty phase, there is little to no participation by the design team or the CM unless there are project problems and at that point in time, the CM shall participate as a referee between the design team and the trade contractors who built the job to the design team documents.

DB begins inherently as a team as the name of the process implies: design team and building team participation. There are large variations of size and commitment by DB teams based on a job-by-job basis and not all these teams embrace the optimum opportunity, which is to achieve single-source responsibility but it can happen based on the following designer and builder team steps (not phases):
  • Concept and cost options
  • Project design-budget intent confirmation
  • Authorization to proceed
  • Finalize and purchase equipment
  • Finalize and purchase remaining trade services
  • Progressively complete field coordinated, record documents
  • Startup of equipment with client
  • Commissioning systems with client
  • Initiate first-year PM plan
  • Trend, assess, and report on project intent during the warranty phase

The designers and the builder along with participation by the owner and/or owner representative complete each of these activities together. Equally important is that the process doesn't have phases. DB has steps not phases and in a seamless process where teamwork is the foundation of the project delivery method. While the CM project delivery method can be successful, the DBB's only feature will probably be lowest first cost. This feature may not necessarily be a benefit because historically DBB will incur the most increase in scope/cost due to changeorders during construction.

My experience has frequently been the DB process approach can frequently create a better solution for less money then the DBB process when compared to design intent, team performance, and final product. The CM process fits somewhere in between DB and DBB.