When the architect exceeds the budget: what the client can do

The budget is part of the design framework. The code of ethics of the Order of Architects of 16 November 2022 requires the architect to submit designs "within the limits of the programme set in the appointment and of the budget" (art. 16, unofficial translation). Any change to the programme "must be the subject of an additional agreement stating its financial impact". The same code requires a written agreement "at the latest once the appointment has been defined" (art. 20).

It is an obligation of means. The architect does not guarantee that the final cost will equal the budget: the architect undertakes to design with the diligence of a professional so that the project stays within the envelope. The commentary by Dirk De Keuster published by Legal News (2019) nevertheless stresses that, within that framework, the burden of proof weighs heavily on the architect when an overrun has to be explained.

The architect's agreement remains the central document. What it says about the budget (amount, price date, items included, any tolerance) takes precedence over any general assessment. How it fits with the works contract is covered in the article on architect and works contracts.

The architect's involvement is required by law, which rules out "replacing" the architect with another party for the design: the article on the architect and mandatory involvement sets out its scope. The client therefore acts within the existing relationship, not alongside it.

No Belgian text sets a percentage beyond which the architect would automatically be liable. The figures in circulation come from court decisions known through secondary sources: they shed light on how judges reason, without binding the judge hearing another case.

The trend in published decisions puts the tolerance at around 10 to 15%. One decision presented 10% of an approximate budget as the admissible limit; others did not accept overruns of 15% and more, or held 17% unacceptable. These decisions have not been read in full here: they are reported by actualitesdroitbelge.be and by the Legal News commentary, and they are cited subject to that reservation.

The Court of Cassation judgment limits the reach of the code of ethics. According to the same secondary source, on 4 November 2004 the Court held that the architect's ethical obligations are not enough to make the budget an essential element of the contract. For the client, the consequence is practical: if the budget matters, it must be stated in the agreement, rather than relying on the Order's code to do so in its place.

The client's cooperation is examined. The source also reports that a client who does not cooperate shares liability for the overrun. A client who has multiplied requests, delayed decisions or refused the savings proposed cannot attribute the whole gap to the architect.

This trend has its limits. It sets no automatic threshold, says nothing about the basis of calculation (works budget or total cost, excluding VAT or not, at which price date) and holds only for the facts judged. Each case is argued on its own documents.

Cases are rarely lost on principle; they are lost on evidence. Four situations recur.

An unwritten budget. An amount mentioned in a meeting, never recorded in the agreement or in minutes, is hard to rely on. The court will then look for what the parties had actually agreed, and doubt does not always favour the party making the claim.

Unrecorded changes. An added room, a higher finish, a building service requested during design: each alters the reference budget. If it was not the subject of the priced additional agreement provided for in article 16, it becomes impossible to separate what lies with the architect from what lies with the client.

An imprecise budget. A bare amount, stating neither exclusion of VAT (HTVA), nor items included, nor price month, compares poorly with a tender. The architect may argue that the gap is explained by price movements or by items the budget never covered.

A warning accepted without reaction. If the architect flagged in writing that the estimate exceeded the budget and the client went ahead without deciding, the argument of non-cooperation becomes serious. A written warning therefore calls for a written decision, even a provisional one.

The logic is gradual: first obtain a project that fits the budget, and only then look at liability. The five steps that follow come in this order, each one leaving a written record.

Before taking any step, quantify the gap properly. Same quantity base, same price date, same items, excluding VAT: without that levelling, the percentage put forward is worthless. The client may have a second estimate prepared by a third party (a métreur, that is a quantity surveyor or construction economist) to document the gap, without that third party taking the architect's place.

The first request is a design request. Since the architect must design within the limits of the programme and the budget, the client can ask in writing for the project to be revised to come back within the envelope, distinguishing what concerns the programme (which the client is or is not prepared to reduce) from what concerns the design. The method is set out in the article on the estimate that exceeds the budget before tendering.

Gather the documents. Architect's agreement, minutes, successive estimates, additional agreements, written exchanges on changes of programme. It is on that basis that the client will show that the budget was part of the appointment and that the gap does not stem from the client's own requests.

If the adaptation is not obtained, put it on a formal footing. A written formal notice recalls the agreed budget, quantifies the gap, refers to the documents and sets a reasonable deadline for presenting a compliant design. It also fixes the date from which the disagreement is established.

Court action comes last. It presupposes a solid file and a gap exceeding what the trend in published decisions accepts, assessed in the light of the client's cooperation. The choice of route and the precise claim are a matter for a lawyer, on the basis of the contract and the facts.

The best protection is built at the start of the appointment. Write the budget into the agreement, with its price date and its items; require a broken-down estimate at each phase; sign a priced additional agreement for each change of programme; decide in writing when a warning is given. The division of roles on cost between architect, quantity surveyor and project manager is explained in the article on the architect, the quantity surveyor and the project manager.

Phase-by-phase checking avoids litigation. A gap spotted at preliminary design stage is corrected by a decision; the same gap discovered when the tenders are opened is settled by a dispute. The checking method is set out in the article on checking the architect's estimate.