Phase Milestones Create Checkpoints That Protect Everyone
The five phases of basic architectural services - Schematic Design, Design Development, Construction Documents, Procurement, and Construction Administration - are defined in AIA B101 Article 3. But milestones within and between phases are equally important: they create formal checkpoints where the owner reviews, comments on, and approves the design before the team proceeds. Understanding what each phase produces, when owner review occurs, and what approval at a milestone means is a core PjM management concept.
Schematic Design (SD)
Schematic Design is the conceptual phase where the architect develops the overall design concept, explores options, and establishes the basic organization and character of the project. SD deliverables typically include floor plans, sections, exterior elevations, site plan, area calculations, preliminary structural system selection, and a schematic estimate of construction cost. The SD phase concludes with an owner review and formal approval to proceed to DD.
Owner approval at SD is significant: it signals that the design concept is acceptable and authorized the team to develop it further. Scope changes requested after SD approval may trigger additional services.
Design Development (DD)
Design Development builds on the approved SD concept to develop systems, materials, and details to a point where the design is substantially resolved. DD deliverables include more detailed floor plans, sections and elevations, structural system design, MEP system design and layouts, outline specifications, updated cost estimate, and identification of long-lead items. The DD owner review is a critical milestone: at DD, the owner should be able to make firm commitments about scope and program before the expensive CD phase begins.
Construction Documents (CD)
CDs are the complete set of drawings and specifications from which the building will be bid and built. The CD phase produces the complete instruments of service: architectural drawings (all disciplines), structural drawings, MEP drawings, civil drawings, geotechnical specifications, and complete project manual (Division 00-49 specifications). CDs are submitted for building permit and issued for bidding. A cost estimate at CD completion should be within 5–10% of the eventual construction bids.
Procurement (Bidding)
During procurement, the architect assists the owner in soliciting and evaluating bids or negotiating with contractors. The architect responds to bidder RFIs, issues addenda to clarify or correct the CDs, reviews bids for completeness, and assists the owner in selecting a contractor. The architect does not typically recommend acceptance of a specific bid (unless requested), as bid evaluation is ultimately the owner's decision.
Design Phase Cost Estimates
| Phase | Estimate Type | Typical Accuracy |
|---|---|---|
| Programming | Order of magnitude | ±30–50% |
| Schematic Design | Conceptual | ±20–30% |
| Design Development | Preliminary | ±10–20% |
| Construction Documents | Definitive | ±5–10% |
| Bids received | Actual | Market price |
Key Exam Points
- Owner approval at each phase milestone authorizes proceeding - scope changes after approval may be additional services.
- SD: concept established. DD: systems resolved. CD: complete instruments of service.
- Cost estimates improve in accuracy through the phases - early estimates have wide tolerances.
- Bidding is a separate phase from CDs - the architect assists the owner during procurement.
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