Not every seller stands on equal legal footing. When the seller has construction expertise, either professionally or by having worked on their own home for years, the burden of proof shifts in favour of the buyer. In this article, we explain when this regime applies, what it means in practice, and how you can demonstrate it.
The legal starting point
In an ordinary sale between private individuals, the burden of proof rests, in principle, on the buyer. You must prove that there is a hidden defect, that it existed at the time of the sale, that it was hidden — and, to obtain additional damages, that the seller knew about the defect. That last element is usually particularly difficult to prove.
But for two categories of sellers, the system works differently. For manufacturers and specialised sellers, a presumption of knowledge applies. The Court of Cassation established this rule in an important judgment of 19 September 1997: if a defect is proven, the specialised seller must compensate, unless he proves that the defect was undetectable.
For you as a buyer, that is invaluable. You no longer need to prove the seller's knowledge. The seller must prove that he could not possibly have discovered the defect.
Who is a specialised seller?
In an important judgment of 15 January 2021, the Court of Cassation refined the definition: the presumption does not rest on every professional seller, but on the manufacturer and the specialised seller, regardless of whether the latter is a professional seller (Cass., 15 January 2021, AR C.20.0241.N).
That is an important nuance. Not every business automatically falls under the regime. The judge assesses on the facts whether a seller can be regarded as specialised, applying the following criteria:
- The degree of specialisation. What specific expertise does this seller have in relation to the type of defect?
- Technical competencies. Does he have knowledge, training, equipment, or experience that would have enabled him to detect the defect?
A contractor who builds homes and sells his own house will almost certainly fall under the regime — especially for construction-related defects. An architect who has realised his own design, equally so. A real estate developer who regularly trades in properties, likewise.
But a dentist who happens to sell a house does not fall under it, however wealthy he may be. The specialisation must directly relate to the type of defect.
And the self-builder?
Here it gets interesting. A DIY enthusiast is generally not considered a specialised seller. But in 2019, the Court of Cassation delivered an important judgment that significantly increased the responsibility of the self-builder.
The facts concerned non-professional sellers who had built their property themselves, without the assistance of a contractor or architect. They had deviated from the original concept of a watertight concrete basement tank. When water infiltration occurred after the sale, the Brussels Court of Appeal — confirmed by the Court of Cassation — ruled that the sellers "should at least have realised that their way of building would give rise to problems", while every prudent self-builder must know that appropriate measures are required to make a basement watertight (Cass., 18 February 2019, AR C.18.0346.N).
The exoneration clause was set aside. The self-builder could no longer hide behind the standard clause.
The lesson: a self-builder is presumed to have minimum basic knowledge of what he is doing. Anyone who deviates from construction standards without consulting a specialist takes a risk — and that risk returns as liability after the sale.
Other examples from case law
Application of the regime against a self-builder:
In a case concerning a house with damp problems, the Liège Court of Appeal ruled that the professional seller who was aware of the defect (damp) and who nevertheless sold the property "as being a normal matter" did not act in good faith and could therefore not rely on the exoneration clause (Liège, 23 July 2021, TBBR 2022, issue 4, 227).
No application — proof of knowledge missing:
A DIY enthusiast who had himself carried out defective works a few years before the sale escaped the warranty obligation because no proof was provided that the deficiencies were already noticeable before the sale (Mons, 31 October 2013, JLMB 2015, 322).
No application — no intent to camouflage:
A seller who had useless roof repair works carried out also escaped, because the court ruled that he thought he had solved the problem — there was no intent to camouflage (Mons, 16 May 2013).
The case law is therefore nuanced: even a DIY enthusiast is given the opportunity to demonstrate that he did not know, and did not reasonably need to know, of the defect.
What does this mean in practice for the buyer?
If you can demonstrate that the seller is to be regarded as specialised, the burden of proof shifts. You still need to prove:
- That there is a hidden defect.
- That it is sufficiently serious.
- That it existed at the time of the sale.
- That it was hidden from you (assessed in abstracto, with your knowledge as the reference).
But you do not need to prove that the seller knew about it. The seller must himself prove that the defect was undetectable for him, and that is a heavy burden of proof.
Moreover, the regime opens the door to additional damages (Article 1645 of the former Civil Code). You can obtain not only a price reduction or refund, but also full compensation — moving costs, temporary rent, professional expert costs, and so on.
How do you prove the seller is a specialist?
Three typical avenues:
Professional activity. Registration in the Crossroads Bank for Enterprises, a diploma or professional association membership, the website or LinkedIn profile, old invoices to other clients — anything that shows the seller is professionally active in the construction sector.
Demonstrable self-performed works. Photos of construction work in progress, permit applications signed by the seller, testimonies from neighbours or suppliers, the post-intervention file included in the sale documents. Anyone who has demonstrably worked on their home for years bears increased responsibility.
The post-intervention file. Since the obligation to include the PIF (post-intervention file) in the sale of houses, this file contains an overview of all works carried out on the property since 2001. It can be a treasure trove of information about who did what and when.
Practical tips
For the buyer: carefully document the seller's status. Ask for the PIF before signing the compromise and read it. Anyone buying a house from a contractor or DIY builder is well advised to have that in writing.
For the specialist-seller: be extra careful with exoneration clauses. A general clause offers you little protection. Work with a lawyer on a specific clause that correctly identifies the known limitations of your property and documents the buyer's acceptance of the risks.
For the full framework of the warranty obligation for hidden defects, consult our pillar on hidden defects in real estate.
Have you bought a house from a contractor, architect, or DIY builder, and encountered a defect? The specialised seller regime can significantly strengthen your position. Contact us at info@reius.be for an initial assessment.