The most common problems in mass timber construction documents are penetrations that are not fully coordinated, tolerances at concrete and steel interfaces that no trade was told about, hardware and coating scopes split unclearly between suppliers, and delegated design scopes without clear criteria. Each one can be found by comparing specific documents before the fabrication release.
Where the problems come from
Mass timber moves decisions earlier, and documents that would be complete enough for concrete or steel can leave gaps. In a Think Wood interview, SmartLam North America CEO Derek Ratchford says that a building designed for concrete and steel and then converted to timber rarely works well. WoodWorks notes in its Index of Mass Timber Connections (updated March 2025) that products vary by supplier in species, geometry, and maximum fabrication size, so early supplier conversations help set grids and connection geometry.
The WoodWorks BC and Seagate Mass Timber checklist (April 2025) collects the questions contractors ask most often. Most of the problems below come from it. Sources verified October 22, 2026. To catch these problems in time, see why mass timber needs earlier drawing reviews. Envelope gaps are covered in mass timber building enclosure details.
Nine common problems and how to check for them
| Problem | Where it shows up | How to check |
|---|---|---|
| Penetrations not fully coordinated | MEP plans show routing lines but not exact opening sizes and locations. | Compare every MEP penetration with the structural panel layout, and confirm each has a size and dimensioned location. |
| No field-cut limit | Specifications are silent on openings cut on site. | Check whether the supplier has defined a maximum field-cut size and whether the trades have been told. |
| Interface tolerances not passed on | Concrete and steel specifications use their normal tolerances at timber bearing points. | Ask whether tighter tolerances are needed at mass timber interfaces, and check that they appear in the concrete and steel scopes. |
| Hardware scope split unclear | Beam hangers, drag plates, and other steel hardware appear in both or neither supplier scope. | Compare the mass timber and structural steel specification sections item by item. |
| Coatings and finishes undefined | Timber and steel coatings are missing from the architectural or structural specifications. | Check that coatings are specified in both sets and that shop versus field application is agreed. |
| Visual expectations not agreed | Exposed delegated-design elements have no stated appearance requirement. | Confirm the design team and owner have agreed what acceptable gaps, checks, and finishes look like. |
| Crane openings missing | The structural set has no detail for crane openings and their infill. | Check that the structure shows where temporary openings go and how they are closed. |
| Delegated design scope unclear | Connection, member, or lateral design is delegated without stated criteria. | Check that the contract documents state performance requirements, load maps, and reactions for the delegated scope. |
| Grids not matched to the supplier | Panel widths and spans do not suit the supplier’s production sizes. | Ask the supplier to review grids and panel layouts before the design is fixed. |
Delegated design is a common gap
Mass timber connections, members, or lateral systems are often delegated to a specialty engineer. WoodWorks explains in its guide to delegated design and design assist that the structural engineer of record remains responsible for code compliance and overall structural integrity, and that the contract drawings and specifications should detail all performance requirements and clearly define scope. It lists load maps for each floor and roof and design reactions by load case as information the delegated designer needs.
When that information is missing, shop drawings stall. Check the structural general notes and the mass timber specification section for the delegated scope, the criteria, and who approves the submittal. The site’s delegated design guide explains the general process.
Find the gaps before the fabrication release
Run the checks above when the design is complete enough to bid, and again before the panel shop drawings are approved. Record each problem with both source sheets and revisions, who must answer, and whether the answer changes the fabrication package. The mass timber drawing coordination checklist covers the full set of items to verify at release.
Where Groundbook fits
Upload the architectural, structural, and MEP drawings with the relevant specification sections, and run a cross-discipline review. Groundbook flags potential disagreements, such as an opening shown on an MEP plan but missing from the structural panel layout, with links to each source sheet. Your team decides what each finding means for the fabrication package. Groundbook does not check structural capacity, fire ratings, or the fabricator’s model.