Who does what in a Belgian construction project?
A Belgian construction project mobilises a dozen professional actors whose roles, responsibilities and warranties differ profoundly. Properly identifying who does what is the condition for a good contract, checking the right certificates and activating the right warranty in case of issue.
At the heart of the system, four actors structure almost every new-build project: the architect (designer and controller, ten-year liability), the contractor (works executor, ten-year and two-year liability), the developer (project seller, subject to the Breyne Law in off-plan sales), and the notary (public officer guaranteeing legal regularity of the deed).
Around them gravitate peripheral but essential actors: engineering office (structure, HVAC techniques, acoustics), surveyor-expert (boundary marking, parcel division), technical inspection body (BCCA, SECO, AIB-Vinçotte for compliance), independent expert (buyer’s assistance) and — in case of dispute — specialised lawyer, judicial expert and business court.
The architect: designer and controller
The architect is the central actor of any project subject to building permit in Belgium. Their mission is framed by the Act of 20 February 1939 on architect title protection (Belgian Official Gazette) and by the ethical regulation of the Order of Architects.
Three main missions:
- Design: sketches, preliminary project, execution plans, permit file
- Coordination: dialogue with engineering office, inspection body, contractors
- Execution control: regular site visits, validation of key phases (foundations, weatherproofing, framing), assistance at reception
Mandatory ten-year insurance. Since the Act of 15 February 2006, all Belgian architects must subscribe to ten-year liability insurance. Demand the certificate before signing the contract — without it, the architect cannot practice.
Fees. Free since 2013, on average 8 to 12% of works cost for a complete mission. Negotiable and to compare with at least 2 other colleagues.
Turnkey case. In a turnkey contract, the architect is part of the package offered by the developer or contractor. You do not choose the architect. Their control mission can be limited, raising questions about defending your interests.
Cluster: Construction architect, Architect ten-year liability.
The contractor: who executes the works
The contractor is the technical actor executing the works. Several configurations exist in practice.
The general contractor coordinates the various trades on the site themselves. They are your single contact and bear overall site responsibility. This is the most common format in Belgium for single-family houses.
The contractor in separate trades: you (or your architect) contract with each trade (shell, carpenter, electrician, plumber, etc.). More complex to coordinate, but more flexibility on choices and sometimes more economical.
The turnkey contractor is a specific format: they sell a finished product (the delivered house or apartment) at a fixed price, under Breyne Law regime. They provide plans, handle permits, execute works and deliver keys in hand.
Mandatory checks before signing:
- Active BCE number for at least 5 years
- VAT registration certificate
- Ten-year insurance certificate in force
- ONSS situation up to date
- 5% security deposit if Breyne Law applies
- Filed balance sheet and financial capacity
Pilot cluster: Construction contractor, New-build house builder, Compare builders.
The developer: project seller
The property developer is the economic actor developing a project from A to Z: they identify the land, buy it, design the programme, mobilise financing, have it built and sell lots (apartments, houses, subdivisions).
Legal framework. The developer operates under sale regime (Article 1583 of the Civil Code). When selling a new-build or under-construction home to a private buyer, they are subject to the Breyne Law: obligation to provide a completion guarantee, payment instalment cap, 5% security deposit, strict formalism of the authentic deed.
Independent developer versus builder subsidiary. In Belgium, many developers are independent SMEs (modest capital, projects targeted on one municipality or region). Others are subsidiaries of large groups (BPI, Matexi, Eaglestone, Cordeel, Thomas & Piron) developing several hundred homes per year. Size is no absolute guarantee but conditions financial solidity and after-sales service.
Pre-signing checks. Beyond standard certificates, examine: 5-year delivery history, average delays between signing and delivery, customer reviews (Trustpilot, Google, forums), judicial disputes (Belgian Official Gazette), the company’s NBB rating. See our developers analysis grid.
Clusters: Property developer, New-build house developer.
“The choice of developer or builder conditions 80% of the quality of the final result. Twenty minutes of upstream analysis avoid twenty months of downstream dispute.”
UPC Belgium, Buyer’s Guide 2025
The notary: guaranteeing public officer
The notary is the public officer responsible for officially recording legal acts in real estate. Their mission is not limited to signing the compromise: they verify the legal, fiscal and town-planning regularity of the transaction.
Four main missions:
- Verification of the seller’s title and absence of easements or mortgages
- Calculation and collection of duties (VAT, registration duty, notary fees)
- Drafting of the authentic deed in compliance with the Civil Code and the Breyne Law
- Custody of funds (deposits, 5% security deposit, completion guarantee)
Notary fees. Rates set by Royal Decree, 1 to 2% of the sale price according to degressive scale.
Choice of notary. You always have the choice of your notary, even if the developer proposes one. In case of disagreement, a notary is appointed by each party and the commission is shared. Never sign with only the developer’s notary if you have doubts.
Technical and inspection actors
Beyond the main legal actors, several technical actors intervene on any complex site:
Engineering office (BET). Calculates structure (concrete, steel, framing), sizes building services (heating, ventilation, electricity), validates acoustics. Fees: 1 to 3% of works cost.
Surveyor-expert. Marks the land, draws up parcel division plans, prepares measurement minutes. Mandatory for any parcel division or disputed boundary.
Technical inspection body (BCCA, SECO, AIB-Vinçotte, OCB). Independent inspection validating compliance with standards (structure, weatherproofing, fire safety, electricity). Mandatory for multi-unit buildings and public buildings, optional but strongly recommended for individual.
EPC officer. Establishes the provisional EPC note then the final certificate. Mandatory for any building permit. Often the architect is also EPC officer.
Safety-health coordinator. Mandatory as soon as at least 2 companies operate on the site (Royal Decree of 25 January 2001). Ensures compliance with safety rules.
The independent expert: your ally
The independent expert is the actor many buyers neglect — wrongly. It is an expert architect or construction engineer appointed personally by the client, independently of all other project actors.
Their added value:
- Total independence: they exclusively defend your interests, unlike the developer’s architect
- Method: systematic checklist, technical measurements, costed valuation of defects
- Experience: has seen dozens or hundreds of sites, identifies recurring pitfalls
- Legal capacity: their report is admissible in court and stands as evidence to start proceedings
When to appoint them:
- Before signing: specifications and contract audit
- Before pre-completion: preparatory visit
- At provisional reception: contradictory assistance and minutes drafting
- At final reception: check on lifting of reservations
- In case of dispute: amicable expert appraisal prior to any judicial action
Cost. Between €450 and €1,200 for a stand-alone reception visit, €1,800 to €2,800 for full advisory (audit + pre-completion + provisional + final). See Breyne Law advisory and Construction audit.
The dispute actors: lawyer, judicial expert, court
When amicable resolution fails, three additional actors step in.
The construction law lawyer. Specialised in Breyne Law, ten-year liability and contractor-developer disputes. Free fees, generally hourly (€180 to €320 excl. VAT in provinces, €250 to €450 excl. VAT in Brussels) or fixed depending on the case. See Construction lawyer.
The judicial expert. Appointed by the judge at a party’s request, they prepare an objective technical report on the defects. Costs advanced by the claimant, generally between €2,000 and €8,000 for a complete expertise. Their mission is defined by summary order. See Judicial construction expertise.
The business court (formerly commercial court). Competent for disputes between buyer and construction professional. Multi-step procedure: introduction by summons, exchange of conclusions, possible expertise, pleadings, judgment. Average duration: 18 to 36 months in first instance.
Conclusion
Building or buying new-build in Belgium mobilises a chain of professional actors each with a specific role, obligations and responsibilities. Properly identifying and choosing them conditions 80% of the quality of the final result.
For the non-professional client, two investments radically change the equation: choosing a solid developer or contractor (verified on at least 6 criteria) and surrounding yourself with an independent expert who exclusively defends your interests at each key step.