The traditional U.S. project delivery method, which typically involves three sequential project phases: The design phase, which requires the services of a designer who will design the project; the bid phase, when a contractor is procured; and a build or construction phase, when the project is built by the contractor. This sequence usually leads to the sealed bid, fixed price contract.
The owner will select a contractor, usually based on the lowest responsive and responsible bid. The selected general contractor will then execute contracts with subcontractors to construct various specialty items. The contractor is responsible for constructing the facility in accordance with the contract documents. The designer typically maintains limited oversight of the work and responds to questions about the design on behalf of the owner.
In DBB, the owner has more control over the design content, relative to other delivery methods. However, this method typically involves a longer time period to execute, in that construction may not begin until the design and procurement phases are complete. DBB is prone to creating more adversarial relationships between all parties when issues develop, as there is no contractual relationship between the contractor and the designer and no opportunity for collaboration during the design phase.
- The majority of design activity fully precedes construction. The owner or other entity sets project goals and uses design services to produce extensive documentation about the project.
- Simpler selection process.
- Final price known (assuming no changes in plans and specifications or unforeseen conditions).
- Owner and contractor have opposite financial interests.
- Incomplete or conflicting contract documents will result in change orders or claims.
- Procedures required to process changes may result in cost to both parties.
- The process may have a longer duration when compared to other delivery methods since all design work must be completed prior to solicitation of the construction contract.
- The designer may have limited ability to assess scheduling and cost ramifications as the design is developed, which can lead to a more costly final product.