Where APD sits, and why it matters
APD holds a particular place in the sequence. Behind it, ESQ and APS have defined the project and tested whether it is economically feasible. Ahead of it, PRO and DCE will produce the contractual documents that go out to tender.
APD is therefore the last design stage before the definitive contractual commitments: the design team's commitment to the forecast cost, settled on the terms of the appointment and no later than the works tender, the client's commitment in lodging the planning application, and the progressive commitment towards construction.
What changes between APS and APD
| Technical options | APS: broad directions. APD: settled choices with sizing data, insulation thickness, duct sections, roof structure type, foundation depth. |
|---|---|
| Economic precision | APS: a global estimate at ±15–20 %. APD: quantities measured element by element at ±10 %, the definitive estimate of the forecast cost. |
| Planning application | APS: not enough data for the application. APD: the complete planning file is produced, site plan, floor plans at 1:100, elevations, sections and description. |
| Coordination of consultants | APS: general coordination. APD: precise coordination between packages, structure and façade interfaces, builder's work openings for services. |
| Contractual liability | APS: a provisional estimate, no commitment. APD: the definitive estimate; the appointment can place the commitment here. |
These levels of precision are orders of magnitude drawn from practice: neither the Public Procurement Code nor the order of 22 March 2019 sets a level of precision for each stage.
The APD deliverables
Architectural deliverables
- ℹ Floor plans, sections and elevations at 1:100: the definitive drawings that make up the planning file. Every opening is dimensioned, floor-to-ceiling heights confirmed, principal builder's work openings shown.
- ℹ Outline specification of the works: a technical description, package by package, of everything provided for. It is the textual base from which the PRO specifications will be written.
- ℹ Planning file: the application form, the planning drawings, site plan, floor plans, elevations, roofs, contextual view and graphic document, the descriptive note, and the preliminary thermal certificate where applicable.
- ℹ First report of the technical control body: on public-access and high-rise buildings, the control body issues a first report at APD. Its observations must be taken up before the application is lodged.
Consultants' deliverables
- ℹ Principle notes by technical package: mechanical and plumbing, covering heating, ventilation and hot water; electrical, covering the load assessment and supply arrangement; structural, covering the foundation system, structure type and loadings.
- ℹ Principle drawings by package at 1:100: schematic layouts of the services, location drawings for the plant rooms, and first coordination drawings showing the interfaces between packages.
- ℹ APD estimates by technical package: each consultant produces its own package estimate, which feeds the economist's overall APD quantities.
The APD quantities: the central cost deliverable
The APD quantities are the most structured economic document of the design stages. Unlike the APS estimate, built on ratios by trade, they descend to the level of individual elements: measurable units, square metres, cubic metres, linear metres or lump sums, each carrying a unit rate.
From an APS estimate to APD quantities: descending to individual elements
APS estimate, by trade: structural works 450,000 € excluding VAT; external joinery 85,000 €; mechanical services 120,000 € and so on.
Structural works, 200 mm reinforced concrete slab: 480 m² × 85 €/m² = 40,800 €
Structural works, 200 mm reinforced concrete wall: 340 m² × 120 €/m² = 40,800 €
Structural works, 400 mm circular column: 18 no. × 1,200 € = 21,600 €
External joinery, single-leaf aluminium window 1 × 1.2 m: 24 no. × 850 € = 20,400 €
This level of detail exposes the items that carry the budget and allows targeted trade-offs where the envelope is exceeded.
Well-built APD quantities are accurate to around ±10 %, an order of magnitude drawn from practice. Set that against the tolerance fixed by the design appointment: failing any mention in the appointment, and where it refers to the 2021 CCAG-MOE, the tolerance attached to the forecast cost is that cost excluding VAT multiplied by 1.05 on new build (art. 13.2), i.e. 5 % above it, a ceiling narrower than this precision.
The design team's commitment on cost: what is contractually at stake
In public procurement, the code does not tie the commitment to the end of APD: the design appointment sets how the forecast works cost to which the design team commits, with its tolerance, is settled (R2432-2), and that cost must be settled no later than the launch of the procedure for awarding the works contracts (R2432-3). The appointment can base it on the definitive APD estimate, or later on the forecast cost the client settles in the light of the detailed design studies (R2431-12, 5°). The settled forecast cost is recorded on the terms of the appointment and is the reference for the first commitment. The appointment may provide for no commitment where it is established that technical data needed to make it cannot be known in time (R2432-5).
| Tolerance | Set by the design appointment (R2432-2). Failing any mention in the appointment, and where it refers to the 2021 CCAG-MOE, art. 13.2 calculates it excluding VAT: forecast works cost x 1.05 on new build, x 1.1 on refurbishment, i.e. 5 % or 10 % above the forecast cost, compared with the tender result. A ceiling on overrun, not a band. |
|---|---|
| First commitment exceeded | Where the appointment covers assistance with awarding the works contracts, the commitment is checked at the end of the works tender: if the tolerance is exceeded, the client can ask the design team to adapt its studies at no extra fee (R2432-3). For design appointments whose tender was launched, or contract notice sent for publication, on or after 1 January 2023, the client can only do so if the overrun does not result from circumstances the design team could not foresee (decree no. 2022-1683). The code attaches no other consequence to this first commitment. |
| Second commitment | Where the appointment also covers site direction of the works contracts and assistance at handover, the design team also commits to the cost resulting from the works contracts, with a new tolerance; failing any mention in the appointment, and where it refers to the 2021 CCAG-MOE, that tolerance is the cost excluding VAT multiplied by 1.03 on new build and by 1.05 on refurbishment (art. 13.2). It is checked after full completion of the works, against the final total cost resulting from the contractors' final accounts and invoices, using the arrangements for changes in economic conditions that the appointment sets. If the tolerance is exceeded, the fee is reduced, using the calculation method set by the appointment, by up to 15 % of the fee for the elements after award of the works contracts (R2432-4). For design appointments whose tender was launched, or contract notice sent for publication, on or after 1 January 2023, only an overrun caused by a failing of the design team in those two duties triggers the reduction; before that, any overrun beyond the tolerance did (decree no. 2022-1683). |
| Outside causes | A change of brief or of services decided by the client goes through a negotiated amendment of the design appointment, which settles the amended brief and the forecast works cost and adjusts the fee and the commitment (L2432-2). Where circumstances arise that the design team could not foresee, the commitment stands, but for design appointments whose tender was launched, or contract notice sent for publication, on or after 1 January 2023, the client cannot ask the design team to adapt its studies at no extra fee if the overrun results from them (R2432-3). Price movements are handled through the arrangements for changes in economic conditions set by the design appointment: the code requires them for the second commitment (R2432-4), and the 2021 CCAG-MOE, where referred to, leaves them to the specific contract documents (art. 13.1). |
Under loi MOP the design team's final remuneration is not fixed when the contract is signed. It is set on the terms of the appointment, APD having to allow the lump-sum fee to be set (R2431-11, 6°): that fee takes account of the forecast works cost, based on either the APS or the APD estimate (R2432-6, 3°), and, until that cost is known, the fee is calculated provisionally on the share of the client's provisional financial envelope allocated to the works (R2432-7). A project dearer than envisaged at the bidding stage can therefore generate higher fees, but the design team then commits to that cost.
APD and the planning application: what to watch
The planning file produced at APD must take up every regulatory constraint identified during the design stages. Several points deserve particular attention.
- ℹ Conditions attached to the permission: requirements from the heritage architect, the fire service or the regional environment authority can force design changes after the application is lodged. Those changes feed back into the APD work and can affect the quantities.
- ℹ Floor area and footprint: conformity with the local plan must be checked. Calculating the regulated floor area, excluding the thickness of insulated external walls and unusable basements, is a frequent source of error.
- ℹ Thermal and environmental certificates: the certificate confirming that the thermal regulation has been taken into account must be produced at application stage. New buildings do not obtain permission without it.
- ℹ Fire safety note: mandatory for public-access buildings. It is examined by the safety commission and can force design changes, compartmentation, smoke extraction, escape routes.
Coordination at APD: the critical interfaces
APD is the stage at which the interfaces between technical packages must be identified and resolved. An interface left unresolved at APD becomes a problem on site, and a source of variations.
| Structure and façade | Openings in concrete walls for the joinery, the junction between concrete frame and cladding, thermal break details: all to be coordinated between the structural consultant and the architect. |
|---|---|
| Structure and mechanical services | Risers for ductwork, suspension points for services at high level, plant rooms and their area, height and access: all to be sized and confirmed by the structural consultant. |
| Mechanical and electrical | Power supplies to the mechanical plant, air handling units, heat pumps, ventilation plant, to be coordinated between the mechanical and electrical consultants. |
| Architect and economist | The schedule of elements in the APD quantities must match the drawings. Anything drawn but not measured is an omission, and an overrun waiting to appear at tender. |
Sources: Léonard Hamburger, Maître d'œuvre Bâtiment, 3rd ed., Eyrolles, 2016 · Yves Widloecher and David Cusant, Manuel d'analyse d'un dossier de bâtiment, 2nd ed., Eyrolles, 2018.
Reference basis of the figures
These bands are orders of magnitude for framing. Unless the page names another area, their reference market is standard provincial France, outside the major cities (regional cost factor 1.00). They serve to place a budget at the earliest stages and to compare building types with one another. They replace neither a tender exercise nor an estimate prepared on drawings, and they are not a record of prices actually charged.
The ratios per square metre and per unit on this page are stated in January 2026 values. They were updated from January 2025 values, the basis retained for this whole group of articles, using the BT01 all-trades index published monthly by INSEE on its 2010 base: 132.0 in January 2025, 134.7 in January 2026, a rise of about 2 %.
Global amounts quoted in worked examples, along with rents, running costs and revenues expressed per year or per night, stay at their original basis: a building cost index does not apply to them.
To bring the ratios forward, apply the usual revision formula: updated value = page value × (BT01 for the month in question / 134.7). The index has kept rising since: it stood at 138.3 in June 2026, the last value published when this page was checked, that is 2.7 % above the reference base. BT01 measures contractors' input costs, wages and social charges, materials, plant and energy, not the prices actually tendered.