For every connection type, confirm that the structural details, the fire-resistance basis, the architectural intent for exposed hardware, the specifications, and the installer’s method all describe the same connection. Settle who supplies each piece of hardware, how the connection is protected for its required rating, and what the special inspector will check before the drawings are released.
Why connections need their own review
WoodWorks’ March 2026 paper Fire Design of Mass Timber Connections (David Barber and Scott Breneman) says the right connection meets several goals at once: finished appearance, structural capacity, price, ease of installation, and demonstrated fire resistance. The architect and structural engineer usually develop the options through design, with input from the contractor or installer, a fire engineer or code consultant, and the authority having jurisdiction (AHJ).
Because so many people shape one detail, each set of drawings can carry a different version of it. The paper also notes that the connection documentation must work for design, pricing, permitting, construction, and inspection. Sources verified October 22, 2026.
Connection types and what to ask about each
| Connection type | What the WoodWorks paper notes | Questions to settle in the drawings |
|---|---|---|
| External metal connectors (hangers, buckets, plates) | Simple to install, but unprotected external steel offers minimal fire resistance. To be fire rated, they are encapsulated with Type X gypsum board, timber, or other designed protection. | Is the connector exposed or covered? If covered, which detail shows the protection, and how are gaps at the board edges sealed as the timber chars? |
| Fully concealed metal connectors | Often proprietary and often pre-installed at the fabrication facility. They usually leave a gap between members that grows with normal timber shrinkage. | Which product is basis of design? Who installs it in the factory? How is the gap between members treated in the fire and finish details? |
| Connections relying on intumescent paint | The paper says intumescent paint has limited use on mass timber connections, because it may not protect the timber and fasteners in contact with the steel. | If paint is proposed, who has analyzed it for this connection, and where is that analysis referenced? |
| Tested connection assemblies | Manufacturers increasingly fire test their connectors. A test report’s criteria, tested parameters, and limitations must be checked against the project. | Do the project details match the tested assembly, including screws, edge distances, and seals? |
Eight questions to answer before the drawings are issued
- Rating. What fire-resistance rating does each connection need, and does the structural detail say so? The paper notes that a connection between rated members needs protection achieving at least the rating of the supported member.
- Compliance path. Is the rating shown by a fire test or by calculation? If by calculation, the paper recommends a pre-submission meeting with the AHJ.
- Exposed or covered. Do the architectural plans, reflected ceiling plans, and details agree on which connections are visible?
- Appearance. For exposed connections, are coatings and finishes stated? The WoodWorks BC and Seagate Mass Timber checklist asks whether exterior or exposed connections are coated to avoid staining, and whether primed steel is acceptable where timber is concealed or encapsulated.
- Hardware scope. Do the specifications split items such as beam hangers and drag plates clearly between the mass timber supplier and the steel supplier?
- Installation. Can the installer reach every fastener after the member is set? Has the installer reviewed connections that need a specific setting order?
- Temporary bracing. Can members be braced without fastening into exposed faces? The checklist also asks whether patching requirements are defined if fastening is needed.
- Inspection. Do the documents state what the special inspector checks? The paper lists items such as screw type and number, minimum edge distances, and the location and type of fire-sealing product, agreed before construction.
Record each question so it can be closed
For each connection type, record the detail references on the structural, architectural, and fire sheets, the specification article, the open question, and who must answer. When a connection changes, check every sheet that shows it, including reflected ceiling plans and finish details. The mass timber drawing coordination checklist covers the rest of the package.
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.