Drawing set phases: SD, DD, CD, IFC, IFB
What each drawing phase contains, who it's for, and how to review documents appropriately at each phase.
Construction drawings are produced in phases, each serving a distinct purpose from design concept through construction. Understanding the phase determines what level of detail to expect, what issues are appropriate to flag, and how ready the documents are for bidding or building. Each phase has a standard abbreviation used in the industry.
SD: Schematic Design
Schematic Design is the earliest phase. The design team explores concepts, spatial layouts, and massing. SD drawings are preliminary sketches showing the architect's vision, not construction documents.
- Conceptual floor plans and exterior elevations
- Building massing and overall footprint
- General area breakdowns (no detailed rooms)
- Preliminary structural grid
- Approximate ceiling heights
- No MEP coordination yet
- Owner/Client, approve design direction
- Design Team, architect, engineers align on concept
- City/AHJ, preliminary zoning and code check
- GC/Estimators, rarely involved; too conceptual
SD drawings are NOT for bidding or construction. Many details change in later phases. Flag major code issues or infeasibility, but don't expect construction-level precision.
DD: Design Development
Design Development builds on Schematic Design. The design is refined, and systems (structure, MEP) are coordinated. DD is more detailed than SD but still not construction-ready.
- Detailed floor plans with most rooms defined
- Building sections and elevations
- Preliminary structural framing layouts
- Rough MEP routing and equipment sizes
- Materials and finish selections
- Detail callouts (not yet detailed)
- Owner/Client, approve design and budget
- Consultants, structural, MEP finalize approaches
- AHJ, preliminary building permit review
- GC/CM, constructability feedback (if hired early)
DD is the phase where major design changes still happen affordably. If a structural approach is wrong or MEP systems clash, fixing it in DD costs much less than fixing it in CD or during construction.
CD: Construction Documents
Construction Documents are the final, complete set of drawings used for bidding and construction. Every detail, connection, and specification is documented. This is the legal and technical basis for the project.
- Complete floor plans, elevations, sections
- All structural connections and details
- MEP systems fully coordinated and detailed
- Finishes, hardware, and equipment schedules
- Large-scale details (interior, exterior, connections)
- Written specifications (CSI format)
- Code compliance notes
- Building Official/AHJ, full permit review
- GC, creates bid estimate and schedule
- Subcontractors, bid on their scope
- Suppliers, order materials
- Owner, final approval before construction
CD is the "legal" document set. Changes after CD are formal Change Orders. This is the appropriate phase for detailed constructability review, code compliance checking, and clash detection. See constructability review and RFI prevention.
IFC: Issued for Construction
IFC marks the moment when drawings transition from design to execution. Once IFC is stamped and signed, the set is ready for on-site use. Typically, CD and IFC are nearly identical, but sometimes minor revisions happen between them.
IFB: Issued for Bidding
IFB (Issued for Bidding) is the set distributed to contractors and subcontractors to prepare their bids. It's usually the same as CD or IFC, but the terminology emphasizes the purpose: contractors are pricing the work.
- Contains all information needed to bid accurately
- Sent to multiple contractors for competitive bidding
- Includes Bid Documents: General Conditions, specifications, unit prices, schedule requirements
- Questions from bidders typically addressed in an Addendum before bid due date
- Becomes the basis for the Contract once a contractor is selected
Typical drawing phase timeline
Here's how the phases typically flow on a project timeline:
Month 1 to 2: SD, Design concept approved by owner
Month 3 to 5: DD, Systems coordinated, budget refined, preliminary permits (if needed)
Month 6 to 8: CD, Full construction documents completed
Month 9: IFB distributed, contractors bid for 2 to 4 weeks
Month 10: Contractor selected, IFC issued, construction begins
(This timeline varies widely based on project complexity, permit requirements, and procurement schedules.)
How to review each phase appropriately
The type of feedback you provide should match the phase:
Focus: Design intent, program fit, feasibility
Examples: Does the building meet the owner’s needs? Is the structural approach sensible? Are major code violations likely?
Guidance: Focus on big-picture issues. Don’t complain about missing details; they don’t exist yet.
Focus: Systems coordination, constructability, budget impact
Examples: Do MEP systems conflict with structure? Is the building method feasible? Are material choices cost-appropriate?
Guidance: This is the phase for constructability feedback. Suggest alternatives if current approach is problematic.
Focus: Completeness, accuracy, code compliance, constructability
Examples: Are all details shown? Does electrical match the single-line? Are schedules consistent with plans? Any conflicts?
Guidance: Detailed review is appropriate here. Flag any missing information, contradictions, or code issues. This is formal review phase.
Focus: Bid readiness, no major changes allowed
Examples: Are all sheets current? Can bidders understand the scope? Any ambiguous areas that will generate RFIs?
Guidance: Focus on clarity and completeness. Major changes require formal Addenda. Minor clarifications can be handled in Addenda.
Common phase-related issues
Watch for these mistakes:
- Treating SD as construction documents: Expecting precision in schematic drawings. Wait for CD for detailed review.
- Making major scope changes in CD/IFC: Large changes require reversion to DD, affecting schedule and budget. Changes after IFC are expensive.
- Issuing IFB with unresolved plan review comments: Bidders don’t know which issues are addressed. Results in RFIs and claim risk.
- Missing the DD phase for constructability input: The best time to flag feasibility issues is DD. In CD, options are limited.
- Not stamping IFC: Unstamped drawings aren’t legal for construction. Always confirm IFC is signed by the design team.
Keep exploring
Related references for reading and reviewing drawing sets.
Plans, elevations, sections, details, and schedules.
What to look for in design and construction documents.
Verifying completeness and accuracy of drawing sets.
Reading revision clouds across drawing sets and phases.