The handoff from design coordination to construction is where unresolved issues in the design model become the GC's problem — and, quickly, the architecture firm's problem. A clean handoff does not guarantee a smooth construction phase, but it changes the starting conditions: the GC's BIM team begins with a federated model that has been systematically coordinated, a documented issue history, and a clear record of every resolution decision made before construction started. That record is the architecture firm's protection when field questions arise about design intent.
Most architecture firms have an implicit handoff process — some combination of the issued construction documents, a closeout coordination meeting, and the model files delivered on a USB drive or shared folder. What most firms lack is an explicit checklist that ensures the handoff package contains everything the GC's coordination team needs to understand the coordination state of the model they're receiving.
What the GC's Team Actually Needs from the Handoff
Before building the checklist, it is useful to think about the handoff from the GC's perspective. When a general contractor begins preconstruction on a project, their BIM team's first task is typically to assess the coordination state of the design models: what has been coordinated, what is still open, and what will need to be redone as the GC brings trade contractor models into a construction-phase coordination workflow.
The GC's BIM team will typically run their own clash detection against the design models — and they will find clashes that were identified and resolved in the design coordination process but are not visible in the issued documents because the model update confirming the resolution was not reflected in the CD set. They will also find clashes that were identified and assigned but not resolved before CDs were issued, because the coordination round completed with open items. Both of these findings generate RFIs that could have been avoided with better documentation.
What a GC BIM team can productively use at handoff:
- The coordinated federated model at the LOD achieved before CD issue (not just the individual discipline models)
- The coordination register — the complete record of every coordination issue identified, assigned, and resolved through the design phase
- Open items documentation — any coordination issues that remained open at CD issue, with responsible discipline, last status, and the resolution path the design team intended
- Model-to-document reconciliation confirmation — confirmation that the issued CDs reflect the coordination resolutions in the model
- LOD status per discipline at CD issue
The Checklist
1. Federated Model Package
Deliver the complete federated model in a format the GC can use. This means the individual discipline model files (not just the federated NWD or IFC) so the GC's BIM team can re-federate with their own trade contractor models. Include:
- Architectural model: Revit RVT (or IFC 4 if the GC's team prefers open format)
- Structural model: same format
- MEP models per discipline: mechanical, electrical, plumbing, fire protection (if modeled separately)
- Coordination NWD or IFC from the final design coordination round
- File revision index confirming each file corresponds to the issued CD set
Do not deliver the federated model without the file revision index. The GC's team needs to know that the model files you delivered match the documents you issued, not a previous coordination round. This is the single most common handoff documentation failure — model files delivered without revision confirmation, creating ambiguity about which models are CD-current.
2. Coordination Register
The coordination register should document every issue identified from Design Development through CD issue. Each entry: Clash ID, date identified, discipline pair, location, severity, responsible discipline, resolution description, model update confirmation date, and closure date. The register format should be accessible to the GC team without requiring access to the design team's project management platform — a PDF export or Excel file, not a login-required web link.
The coordination register is the primary reference when a field question references a design-phase coordination decision. The GC's superintendent asks why the HVAC main trunk routing on Level 3 takes a specific path — the coordination register entry explains that the original routing conflicted with the moment frame and was revised in coordination round 8 of Design Development. That entry is the documentation of design intent; without it, the question becomes an RFI and the architecture firm has to reconstruct the decision from meeting notes and email threads.
3. Open Items Log
Every coordination program has open items at CD issue. Some are deferred by design intent (items that will be coordinated by the GC through the shop drawing process). Some are genuinely unresolved issues that should have been resolved but weren't. Some are preliminary flags from earlier coordination rounds that were superseded by design changes but never formally closed.
The open items log should distinguish between these categories explicitly. Deferred-by-intent items should note who made the deferral decision and why. Genuinely unresolved items should be flagged as requiring resolution before construction proceeds in the affected zone. Items that were superseded should be documented as such — if the GC's team finds them in the model, they need to know these are not active issues.
Delivering an open items log that mixes deferred-by-intent items with genuinely unresolved coordination conflicts is a setup for CA disputes. The GC's team encounters what they believe is an unresolved design issue; the architect says it was deferred by intent; neither party can document that decision because the open items log doesn't distinguish the categories.
4. BIM Execution Plan Reference
The design-phase BIM Execution Plan documents the LOD targets, coordination protocol, and model delivery standards that governed the design coordination process. The GC should receive a copy — not because they are bound by the design BEP, but because it tells them the assumptions that underlie the coordination they're receiving.
Specifically: the GC's team needs to know what LOD was targeted and achieved per discipline, what coordination tolerance settings were used in the clash detection runs, and which discipline was responsible for which model categories. Without this context, the GC's BIM team cannot correctly evaluate the completeness of the coordination they've been handed.
5. CD-to-Model Reconciliation Confirmation
This is the confirmation that the issued construction documents reflect the coordination resolutions in the model. It does not need to be an exhaustive element-by-element audit — it needs to confirm the specific coordination items where model changes were made and CD drawing updates were required.
The practical form: a signed statement from the project architect confirming that coordination resolutions affecting issued drawing content have been incorporated into the CD set, with specific reference to any resolutions where the document update is pending (i.e., the model was updated, the CD update is in the next addendum). This gives the GC's team a documented baseline and clearly identifies any remaining document gaps.
The Handoff Meeting
The formal handoff is not a file transfer — it is a meeting. The BIM Coordinator and project architect should walk the GC's BIM manager through the coordination state of the model: the zones that received intensive coordination attention, the open items and their status, any known complex coordination conditions that the trade contractors will encounter. This meeting should happen before preconstruction starts, not after the GC has already run their own clash detection and found issues that weren't documented.
We are not saying the design team's coordination is perfect or that the GC should trust it without verification — GC preconstruction coordination will find things the design team missed, and that is appropriate. The goal of a clean handoff is not to prevent the GC from finding issues; it is to ensure they have the documentation context to evaluate what they find, distinguish new construction-phase conditions from unresolved design-phase issues, and start their own coordination process from a well-documented baseline rather than an undifferentiated model dump.
The firms that handle this handoff well consistently report shorter RFI volumes in the first 60 days of construction. That is not a coincidence — it reflects the difference between a GC team that starts construction knowing the coordination state of the model and one that discovers it by running their own analysis from scratch during preconstruction.