Project Owner and Lead Designer: Who Does What on a Construction Project
Lead designer (maître d'œuvre) vs project owner (maître d'ouvrage): clear differences, duties, responsibilities and how to choose the right partner to make your construction project a success.
💡 In brief
The project owner (MOA, maître d’ouvrage) commissions the work: they carry the need, provide the funding and make the final calls. The lead designer (MOE, maître d’œuvre) designs the project and coordinates its execution on the owner’s behalf. Telling these two roles apart avoids contractual misunderstandings and keeps the project running smoothly. On modern projects, BIM and a French collaborative platform such as Kroqi make collaboration between them easier, from design through to handover.
Are you starting a construction project and the roles are getting muddled? The terms lead designer and project owner are often wrongly used as synonyms, yet the distinction between them is the cornerstone of every contractual relationship in the building industry. This article clarifies who does what, sets out the precise duties of each, gives practical advice for working well together and shows how BIM, on a collaborative platform like Kroqi, now makes this dialogue easier from the programming stage through to the handover of the building.
What is the fundamental difference between a lead designer and a project owner
The distinction fits in one sentence. The project owner is the one who has the building built. The lead designer is the one who has it built for them. The former carries the decision and the funding, the latter the design and the coordination. The table below sets the two roles side by side on the practical questions that arise on every project.
| Question | Project owner (MOA) | Lead designer (MOE) |
|---|---|---|
| Who decides? | The client: they commission the work | The designer: they propose and carry out the technical side |
| Who pays? | They fund the project and pay for the services | They are paid by the MOA under a project management contract |
| Who defines the need? | They write the functional brief | They turn the brief into a buildable project |
| Who runs the construction site? | They approve and arbitrate strategic choices | They are in charge of directing the execution of the works (DET) |
| Who signs the contracts? | They sign with the contractors | They assist the MOA but do not sign on its behalf |
| Who accepts the works? | They sign the acceptance report | They assist the MOA and support the clearing of reservations |
| Legal framework | Public procurement code (CCP, book IV); Civil Code for private contracts | MOE contract governed by the CCAG-MOE in public contracts |
The project owner, the client who gives the orders
The MOA is the individual or legal entity for whom the building is built. They decide what to build, where, at what cost and on what timetable. In practical terms, they are the client who gives the orders.
This role covers a wide variety of profiles: a municipality having a school built, a social landlord refurbishing a block, a developer launching a residential scheme, or simply a private individual building their own home. All of them hold the same legal role, under different regulatory frameworks.
The key decisions belong to the MOA: functional brief, budget, schedule, choice of the lead designer, approval of the design phases. They are the one who accepts the building at handover.
The lead designer, the conductor of the design
The MOE designs and coordinates the project on behalf of the MOA. They turn the statement of need into a buildable project, direct the technical studies and supervise execution on the construction site.
The project management team brings together several technical profiles: lead architect, technical engineering offices (structure, MEP, thermal), construction cost consultant, OPC. On complex projects, several providers join forces in a joint-contracting group.
The MOE makes the technical decisions: architectural choices, structural sizing, development of the execution drawings, organization of the construction site. But they never sign contracts in place of the MOA. They assist, advise and coordinate.
What exactly is the role of the project owner on a project
Before construction: programming and funding
Before anything starts, the project owner takes on five key tasks:
- Define the functional brief: intended use of the building, floor areas, environmental requirements, site constraints.
- Set the financial envelope with a realistic estimate and margins for contingencies.
- Draw up the provisional schedule, taking administrative lead times into account (permits, appeals).
- Choose the lead designer and the other service providers (AMO, technical inspection, SPS coordinator).
- Start the formalities: permit application, insurance, prior declarations.
This early phase conditions everything that follows. A vague brief produces a vague project. A poorly framed budget produces a string of change orders. To steer these decisions and trace every trade-off, you can rely on the platform dedicated to project owners, which centralizes the project documents in a shared repository.
During and after construction: arbitrating and accepting the works
Once the construction site is under way, the MOA no longer intervenes directly in the works. They do, however, continue to arbitrate strategic decisions: significant contingencies, variant requests, changes to the brief.
At handover, the MOA is the central player in the acceptance of the works. They sign the acceptance report, draw up the list of reservations and follow their clearing. This step is crucial: acceptance triggers the warranty periods set out in articles 1792 and following of the French Civil Code: the completion warranty (1 year), the two-year functional warranty (2 years) and the ten-year warranty (10 years).
Beyond acceptance, the MOA inherits the building. They become its operator or entrust it to a third party. The project therefore does not really end at handover: it enters its operating phase, which can last several decades.
What exactly is the role of the lead designer on a project
Design phases
On the project management side, the basic mission for building works is defined in article R2431-7 of the Public Procurement Code. It comprises eight successive regulatory elements: ESQ (sketch design), APS (preliminary design), APD (detailed preliminary design), PRO (project design), ACT (assistance with the award of works contracts), EXE/VISA (execution studies or approval of the studies made by the contractors), DET (direction of the execution of the works contracts) and AOR (assistance during acceptance operations and during the completion warranty period). OPC (scheduling, steering and coordination) can be added as an option, depending on the complexity of the project.
During the design phases, the MOE progressively produces the project documentation, from the initial intent through to the tender documents for contractors. Each phase is explicitly approved by the MOA before moving on to the next.
Coordination between disciplines is the other critical dimension. Architect, structure, MEP, thermal: each specialty must be aligned with the others. The Kroqi module dedicated to project management centralizes this coordination and tracks every version of the drawings.
Execution and closing phases
During execution, the MOE directs the works. They visit the construction site regularly, run the weekly meetings, approve the execution drawings produced by the contractors and validate the progress payment statements.
Document approvals are one of the characteristic outputs of the MOE during execution. Every drawing, every data sheet, every method goes through an approval workflow: approval issued, approval with comments, rejection. This discipline structures the quality of the delivered project.
At handover, the MOE supports the MOA. They draw up the list of reservations, follow their clearing and formally close the project management missions.
How to work effectively with a lead designer when you are the project owner
Frame the need before signing
Express your need clearly before signing the project management contract. The more precise the brief is up front, the fewer costly trade-offs will arise during the project.
Frame your budget envelope realistically: an underestimated envelope creates constant tension during execution and opens the door to a string of change orders.
Finally, specify the expected level of finish (standard, superior, high-end). These choices drive costs but also the final feel of the delivered project, and must be explicit from the outset.
Steer the relationship during the project
Hold regular meetings with your lead designer. Monthly during the design phase, weekly during the construction phase. Each meeting produces dated minutes that formalize the decisions and the actions to be taken.
Explicitly approve each phase before moving on to the next. This discipline avoids costly backtracking. A validation traced by electronic signature gives legal value to the successive trade-offs.
Share a common platform with your project management team. All the project documents (drawings, minutes, data sheets, approvals) are versioned and traceable there. This way you avoid divergent versions and loss of information.
How BIM transforms collaboration between lead designer and project owner
A shared digital model as the common reference
BIM (Building Information Modeling) changes the very nature of the dialogue between MOA and MOE. The 3D digital model becomes the reference shared by everyone involved in the project.
For the project owner, this is a considerable gain. 3D visualization makes it possible to understand the project without interpreting technical 2D drawings, to spot what does not match the initial expectation and to make decisions with full knowledge of the facts. The methodological framework for this collaboration is set by the ISO 19650 standard, which structures BIM information exchanges throughout the project.
BCF annotations placed on the model replace the vague remarks of paper minutes. A change request becomes a located ticket, linked to a trade package and a deadline for handling.
A common data environment to trace every decision
The common data environment (CDE) provided for by the ISO 19650 standard centralizes all the project documents. Drawings, models, minutes, photos, approvals: each item carries a status, a timestamp and an identified author.
This discipline transforms the traceability of the project. At any time, you can find out who approved what, on what date and with what comments. This is valuable during the project, and indispensable in the event of a later dispute.
The history remains auditable through to operation. The delivered model becomes the basis of the digital twin of the building, which extends the value of the project over its entire lifetime.
How to choose the right platform to steer your project
For a public or private project owner
If you are a project owner, several criteria guide your choice. Data sovereignty comes first: for public contracts and sensitive projects, hosting on French territory and GDPR compliance are essential, complemented by the NIS2 directive (transposed in France in October 2024) and, for the most critical workloads, by the ANSSI SecNumCloud 3.2 qualification, which requires immunity from extraterritorial laws.
The ability to bring the whole project team together matters just as much: MOA, project management team, contractors and operator must all be able to access it with differentiated rights. A proprietary platform that requires the use of a single business software excludes some of the stakeholders.
Steering of trade-offs and traceability completes these criteria: you must be able to check at any time the progress of the project, the decisions taken and the versioned documents.
For a project management team
If you are a lead designer, your criteria are complementary. Compatibility with the engineering offices’ business tools is paramount. The platform must support IFC imports and exports and exchange smoothly with modeling tools and calculation solutions.
Coordination and document approval tools are at the heart of the job: configurable approval workflows, auditable statuses, electronic signature compliant with the eIDAS regulation (EU 910/2014). These functions structure the quality of execution.
Finally, the mobile app for the field has become indispensable. Site visits, geolocated photos, annotations directly on the model: all from a smartphone or tablet, with synchronization when connectivity returns.
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