Design-Bid-Build (DBB) is the traditional, linear project-delivery model: the owner first contracts an architect/engineer (A/E) to complete the design, then competitively bids the finished construction documents to general contractors, then contracts a winning builder to construct exactly what was drawn. Three parties, three separate contracts, three sequential phases — design fully resolved before price is fixed and before a shovel moves.

DBB is defined by separate, sequential contracts between three parties

The defining structural feature of DBB is the absence of a single point of responsibility for both design and construction. The owner holds two prime contracts that never touch each other:

• Owner ↔ A/E (design contract) — typically an AIA B-series owner/architect agreement (e.g., B101). The A/E produces the design and the construction documents and usually provides construction-phase services (submittal review, RFI responses, payment certification).
• Owner ↔ General Contractor (construction contract) — typically an AIA A-series owner/contractor agreement (e.g., A101 with A201 general conditions), awarded after design is complete and bids are received.

The general contractor in turn holds subcontracts with trade subcontractors (mechanical, electrical, plumbing, fire protection, low-voltage, etc.) and purchase orders with suppliers. The A/E and the GC have no contract with each other — they coordinate through the owner and the documents.

This three-party / two-prime arrangement is the root cause of nearly every DBB characteristic discussed across this Part: the owner sits between design and construction, carries the design risk (the "spearin doctrine" implied warranty that the documents are buildable), and absorbs the gap whenever the drawings and the field disagree. (Risk allocation is covered in depth in the Contract & Risk sibling Article; this Article focuses on the model and its sequence.)

The model runs as three strictly sequential phases

DBB's name is its sequence. Unlike collaborative models that overlap design and construction, DBB completes each phase substantially before the next begins.

The key consequence: in pure DBB, the builder has no input into the design and the price is not known until design is essentially finished. Cost certainty arrives late, collaboration arrives never (during design), and any constructability or pricing problem discovered after award becomes a change order rather than a pre-construction conversation.

Phase 1 — Design: the A/E completes the documents through escalating detail

The design phase itself is conventionally broken into progressing levels of resolution. Each stage adds detail and typically gets an owner cost check and approval before proceeding:

• Programming — the owner (often with the A/E or a separate planner) defines the functional program: department adjacencies, room-by-room requirements, departmental gross square footage, and operational assumptions. For healthcare, this is where the program is reconciled against clinical workflow and code-driven space needs.
• Schematic Design (SD) — overall building organization, massing, major systems articles, and a first-order cost estimate.
• Design Development (DD) — systems and assemblies are fixed: structural grid, MEP system selection and sizing, envelope, key sections and details. Estimates tighten.
• Construction Documents (CDs) — the full drawing set and project manual (specifications) drawn to a biddable, buildable, permittable level of completeness. In DBB, this set must be essentially complete because the contractor will bid and build from it with no design authorship.
• Permitting / AHJ review — the completed documents are submitted to the authority having jurisdiction (the local building department, the state hospital-construction review agency where one exists, the fire marshal, and the health department). The documents must satisfy the applicable building code (IBC) and the health-occupancy overlays before construction can begin.

Because DBB hands the contractor a finished, owner-warranted document set, the completeness and coordination quality of the CDs is the single biggest driver of DBB outcome. Gaps, conflicts, and missing details that a collaborative model would surface during preconstruction instead surface in the field as RFIs and change orders.

Phase 2 — Bid: price is competed against the completed documents