Mass timber needs drawing reviews earlier because penetrations, connections, and interfaces are fixed when the panels are fabricated, long before installation. Plan reviews at design milestones and before the shop drawing push, so coordination is finished while changes are still cheap.
Coordination moves months earlier
In a WoodWorks workshop presentation on mass timber schedule management (November 2019), Swinerton Mass Timber described the goal as coordination occurring 3 to 6 months earlier in the project than conventional practice, and called it a big shift. The same presentation says all factory penetrations must be finalized during the shop drawing process, and that other structural trades must have their shop drawings and 3D model approved and locked for fabrication before timber detailing starts, or risk rework.
WoodWorks guidance on holes and penetrations recommends modeling as many openings as possible so the manufacturer cuts them. The WoodWorks BC Mass Timber Construction Success Checklist (April 2025) warns that penetrations not fully coordinated before tender can delay fabrication. Sources verified October 22, 2026.
What late coordination costs
The Swinerton presentation lists the effects of late answers. Lingering questions from shop drawing review could drag on for weeks or months if not addressed definitively. If the delivery method does not allow early constructability review, the team should budget more time for RFIs and shop drawings. It also notes that manufacturer availability was ranging 3 to 10 months out at the time, so a delay in the drawings can push a production slot.
Once a panel is cut, a missing opening becomes a field cut that the engineer and supplier must accept, or a replacement panel. Both cost more than a comment on a drawing.
When to review, and what each review settles
| Milestone | Review focus | Why it matters for timber |
|---|---|---|
| Schematic design | Grid, spans, panel direction, and the structural system across disciplines. | Grid and span choices drive panel sizes, repetition, and cost. |
| Design development | Construction type, exposed and protected timber, main MEP routes, shafts, and large openings. | Major openings and service zones are easiest to change before structure is detailed. |
| Construction documents | Every penetration, connection, and interface with concrete and steel across all disciplines. | This is the set the fabricator details from. |
| Before shop drawings | Open questions and RFIs from earlier reviews, plus any late MEP changes. | The presentation says factory penetrations are finalized during shop drawings. |
| Shop drawing review | Fabricator drawings against the contract drawings and specifications. | The last chance to fix information before the panels are cut. |
Make early reviews count
- Review all disciplines together. Most timber problems sit between the MEP plans and the structural panel layout, so a single-discipline review misses them.
- Include the specifications. Field-cut limits, hardware scope, moisture limits, and finish requirements often live only in the specifications.
- Close every comment. Track each question to a decision and a revised sheet. An open comment at shop drawings is the kind of lingering question the Swinerton presentation warns about.
- Recheck each revision. A design change after a review can reopen interfaces that were already settled.
Where Groundbook fits
Groundbook reviews the drawings, specifications, and references you upload and flags potential conflicts with links to each source sheet. Use a cross-discipline review at each milestone. When the revised set comes back, a recheck shows which earlier issues are Fixed, Still Open, or New, and keeps every review version. Your team decides what each finding means. Groundbook does not check structural capacity, fire ratings, or the fabricator’s model.