The architect, the consulting engineer, the cost consultant and the project manager

Each party is judged on three questions: what must they do on cost, on what basis, and what do they not guarantee. The table can be used as a checklist for reading agreements before signing.

The first obligation is one of form: a written agreement. Under Article 8 of the Grand-Ducal Regulation (règlement grand-ducal) of 17 June 1992, "for every brief, an agreement must be drawn up in writing and signed by both parties, at the latest when the brief has been defined" (unofficial translation). It is in this agreement that the budget becomes enforceable.

The second is one of substance: staying within the budget. Article 9 requires the submission of "designs which remain within the limits of the programme set in the brief and of the budget that follows from it, in accordance with the agreement concluded between the parties". Any significant change to the programme, during design or on site, calls for an additional agreement "which shall state its financial impact". The obligation therefore applies to the budget in writing; a verbal or undated budget makes it hard to rely on.

The third concerns the tender process. The architect assists the client in choosing the firms involved "with a view to carrying out the project on the best terms of price and quality" (Art. 13); in a tender, the architect ensures "equal opportunity for competitors, while assisting the client" (Art. 14). For a developer building to sell, Article 12 also asks the architect to look after the legitimate interests of users and future buyers, which may weigh on some cost-saving decisions.

What the architect does not guarantee: tender prices. The architect estimates; contractors price. When the gap exceeds what the agreement allows the client to accept, the remedies are covered in the article on when the architect exceeds the budget; no numerical tolerance has been identified in the Luxembourg texts and decisions reviewed.

Using an architect is sometimes compulsory. The cases and the content of the file belong to the building permit: see the article on assembling a permit application. The professions concerned and the position of firms established abroad are set out in the article on the construction professions concerned.

The 1992 regulation applies to architects and consulting engineers in the same terms. The consulting engineer also owes a written agreement (Art. 8) and designs within the budget (Art. 9), and is subject to the same incompatibility with contracting.

Its weight in the budget is often underestimated. Structure, foundations, building services and energy performance account for a large share of the cost, and the related choices sometimes come late in the design. The client has every interest in requiring the consulting engineer's estimate to be prepared at the same base date and with the same breakdown as the architect's, so that the two add up with no gaps and no double counting.

When the consulting engineer is the architect's subconsultant, the client has a contract only with the architect; when the engineer is appointed directly, the client has two agreements to coordinate. In both cases, the rule in Article 15 applies: where members work together, roles, responsibilities, insurance and fees are set out in writing.

The incompatibility is absolute in principle. Practising on an independent basis is "always incompatible with the profession of contractor for any construction works", whether directly or through an intermediary (Art. 4 and 5). The designer therefore cannot itself be a party, as contractor, to the works contracts it designs.

Independence is not accuracy. It rules out conflicts of interest, not estimating errors or an optimistic preliminary design. That is the reason for a check by a third party, described in the article on the independent counter-estimate.

On fees, Article 19 must be read together with the 2024 decision. Article 19 of the regulation prohibits members from taking part in tenders that put the price of their services in competition; but in the commitments made binding by decision No 2024-E-01 of the Competition Authority (Autorité de la concurrence), the OAI, the order of architects and consulting engineers, undertook not to bring any disciplinary proceedings on that basis and reminded its members that they are free to negotiate their fees with public-sector clients.

No regulation specific to the cost consultant has been identified in the texts reviewed. The title alone therefore guarantees neither training, nor insurance, nor independence: these points must be checked and written into the agreement.

The role breaks down into dated deliverables. Estimate at each stage (sketch design, preliminary design, detailed design), counter-estimate, check of the quantities and the bill of quantities before tender, tender analysis, monitoring of the forecast final cost, preparation of the final account. Each deliverable should state its basis (drawings of which date), its base date, its scope (works only or total cost) and the expected level of accuracy.

In a public contract, two clauses matter. First, the cost consultant's estimate may serve as the basis for the contracting authority's estimate (devis), which must not be disclosed to tenderers (Grand-Ducal Regulation of 8 April 2018, Art. 45 (5)): the agreement must therefore impose confidentiality. Second, the examination of tenders may call on experts (Art. 80 (1)): the brief must say whether the cost consultant assists at that stage and in what form.

Independence is a matter of contract. In the absence of any legal incompatibility identified, the client can require a declaration that there are no links with the contractors invited to tender, and a ban on working for them on the same project.

The project manager has no specific legal status identified either. The role is defined by what it involves: programme, flow of information, preparation of decisions, keeping the cost dashboard, meeting reports.

The critical point is the limit of the mandate. Can the project manager approve a change of programme, accept a price, sign an amendment (avenant)? Without a written mandate setting its scope and a ceiling, the answer should be no: the project manager prepares, the client signs. A mandate that is too broad shifts the budget decision without the client noticing.

The client is better off setting the split of roles itself, rather than inferring it from separate agreements.

Ten-year liability does not cover the budget. Article 1792 of the Civil Code makes architects, contractors and other persons bound "to the client" (maître de l'ouvrage) by a contract for works (louage d'ouvrage) liable for 10 years where the building is destroyed through a construction defect. Keeping to the budget, by contrast, is a matter for the agreement. The insurance regime, including whether certain cover is compulsory, which has not been checked here, is covered in the article on insurance and liability: ask each party for their certificate and the scope of their cover.