Here is a high-level comparison of the three construction delivery methods. The table below shows, in simple terms, who the district hires, when the builder becomes involved, and how the project moves from design to construction.
In simplest terms:
- Design-Bid-Build (DBB): Design, then one bid, then build (construction)
- General Contractor/Construction Management (GC/CM): Hire the designer and builder separately, but bring the builder in early
- Progressive Design-Build (PDB): Hire one team to design and build the project
High-Level Comparison of DBB, GC/CM, and PDB
| Characteristic | Design-Bid-Build (DBB) | General Contractor/Construction Management (GC/CM) | Progressive Design-Build (PDB) |
|---|---|---|---|
| Basic approach | Design first, then bid construction | Bring the contractor into the project during design | Bring a combined design and construction team into the project during design |
| School District's contracts | Separate contract with designer and contractor | Separate contract with designer and GC/CM | One contract with a design-builder |
| Who designs the projects? | District's Architect/Engineer | District's Architect/Engineer | Design-builder |
| When is the contractor involved? | After design and competitive bidding | During design | During design from the early stages of the project |
| Does the contractor participate in design? | Generally not | Yes | Yes |
| Who does the designer work for? | School District | School District | Design-builder |
| Relationship between designer and contractor | Separate | Separate, but they work together during design | Part of the same team |
| How is construction cost established? | Competitive bids based on completed construction documents | MACC negotiated with the GC/CM as the design progresses | Final GMP is developed after the design-builder has been selected and the project is further developed collaboratively. |
| Can construction begin before the entire design is complete? | Generally, no, and not when applying for SCAP funding. | Yes, in general. GC/CM can use early construction packages to begin portions of the work before the entire design is complete. For SCAP-funded projects, however, building construction cannot begin until the Final GMP Amendment and D-10 or D-10(1) have been issued. | Yes, in general. PDB can overlap design and construction, using construction packages as the design develops. For SCAP-funded projects, however, building construction cannot begin until the Final GMP Amendment and D-10 or D-10(1) have been issued. |
| Defining characteristic | The building is generally designed before construction begins, with one competitive construction bid. | The contractor is involved early, but the designer and contractor remain separately contracted with the district. | The designer and contractor are part of one team under a single contract with the district. |