Buyer guides · Procurement and contracts · 12 min
Modular building responsibility matrix: close the gap between factory and site
Most modular disputes begin at an interface both parties assumed the other owned. A responsibility matrix turns those assumptions into named work and evidence.
Published by AeroPodHomes · Updated 30 August 2026
Write activities, not department names
A useful matrix does not say factory, contractor or client in broad blocks. It lists the action: issue support loads, design foundations, book freight, verify access, provide crane, inspect receiving condition, make the roof joint, connect water, test drainage and close defects. Each line gets one accountable owner.
Add the supporting roles that provide information, review or perform work. Record the required input, due date and acceptance evidence. A name without a deliverable still leaves room for two parties to believe the same task sits elsewhere.
Divide design by interface
Separate product design from site design. The manufacturer defines the module, agreed structure and envelope, service terminations, support points, weights and installation requirements. Local professionals normally address surveys, ground conditions, foundations, site drainage, utility networks, local code coordination and external works.
Name who checks the combined condition. A support drawing can be correct and a foundation design can be correct while their grids or levels still conflict. The matrix should include a coordination and approval line for every physical interface.
Carry ownership through logistics
Assign export packing, loading, commercial documents, carrier booking, insurance, import, port handling, final haulage, route permits, escorts, crane, forklift, laydown and waste removal. State the Incoterm separately; it allocates commercial delivery obligations but does not by itself describe every technical site activity.
Record who inspects condition at handover points and the time allowed to report damage. Match the loading plan to the receiving sequence so the site can reach the units and loose components in the order they are needed.
Make installation boundaries physical
List supports and shims, module positioning, temporary stability, opening or assembly, structural joints, roof and wall seals, loose panels, external trims, doors and windows, service connections, stairs, decks, skirting and reinstatement. Mark the exact point where factory scope ends and local work begins.
For every site connection, identify the drawing, material supplier, installer, inspection and test. Weatherproofing and drainage deserve special attention because a small unowned joint can create a large defect across product and site scope.
Use commissioning to prove the handover
Assign electrical tests, water pressure and flushing, drainage, hot water, HVAC start-up, controls, ventilation, alarms, doors, windows, seals and snagging as applicable. State who provides power, water, consumables, instruments and access for each test.
Handover should include results, as-built records, manuals, equipment data, training, spares, warranty start and the open-item register. Occupancy is a project outcome; no single supplier can declare it without the site and local systems being ready.
Keep the matrix alive after the contract
Update the matrix when scope, route, installer or design changes. Review it at design freeze, before shipment, before site mobilisation and before commissioning. Closed activities can carry links to their records rather than disappearing from view.
For defects, name the first diagnostic owner and required evidence. A leak, electrical trip or damaged finish can cross manufacturing, transport and installation boundaries. The response path should begin with facts and inspection, not an argument over who answers the first email.
Decision table
| Interface | Factory-side output | Destination-side output |
|---|---|---|
| Ground and supports | Loads, points and tolerances | Survey, design and constructed supports |
| Utilities | Termination locations and loads | Networks, connections and local tests |
| Logistics | Packing, loading and shipment documents | Import, route, haulage and receiving |
| Installation | Instructions and product materials | Plant, labour, method and site safety |
| Approval | Agreed technical product documents | Local design, application and authority liaison |
| Commissioning | Product test requirements and records | Site systems, final tests and occupancy release |
| Warranty | Covered product scope and response route | Site records, access and local-work evidence |
Common questions
What is a modular building responsibility matrix?
It is a line-by-line allocation of design, approvals, factory, logistics, site, installation, testing, handover and warranty activities, with one accountable owner for each.
What is normally outside a modular manufacturer’s scope?
Local surveys, foundations, roads, cranes, utility networks and connections, installation labour and permits are commonly buyer-side unless the contract explicitly includes them.
Does an Incoterm define the installation scope?
No. Incoterms allocate named commercial delivery obligations and risk points. A separate technical scope and responsibility matrix are still required.
Who designs the foundations?
The manufacturer supplies agreed loads, support points and tolerances. A qualified local professional normally designs the ground solution for site conditions and local requirements.
When should the matrix be updated?
Review it at design freeze, route confirmation, shipment release, site mobilisation and commissioning, and whenever a design, contractor, scope or sequence changes.
Technical references
External references support the process and standards context. Project-specific design and approval remain subject to the appointed destination professionals.