Is the seller liable for building materials containing asbestos if he himself did not know of their existence?

Asbestos liability 2026

In principle, a private seller in Switzerland is not liable if he demonstrably had no knowledge of the asbestos-containing building materials and a warranty disclaimer was agreed in the purchase contract. In buildings built before 1990, a buyer must now assume that asbestos may be present. Liability only occurs when the seller has fraudulently concealed the defect or has given a specific assurance that it is free from harmful substances.

The disclaimer of warranty in the standard contract

In Swiss legal practice in 2026, it is absolutely common for liability for physical defects to be contractually waived when selling existing real estate. This clause protects the seller from having to take responsibility for defects that he himself was not aware of. Since asbestos-containing substances are usually firmly bound and invisible to the naked eye, they are considered hidden defects. If the seller can therefore demonstrate that he had no evidence of a charge during his period of possession, the agreed disclaimer usually applies in full.

For the buyer, this means that he largely bears the risk of future restructuring costs himself. The Federal Supreme Court has confirmed in settled case law that the mere presence of firmly bound asbestos (e.g. in eternite plates or tile adhesive) does not constitute a defect that restricts the normal use of the apartment. Only when the fibers are released as a result of damage or aging and there is an immediate health risk does the legal assessment change. But even here, the burden of proof remains with the buyer, unless the seller was aware of it.

Malicious as the only breach of immunity

A buyer's only effective weapon against the exclusion of warranty is proof of fraudulent misrepresentation in accordance with Art. 199 OR. Fraud is used when the seller was aware of the defect or at least had a specific suspicion and deliberately concealed this from the buyer. A typical example in 2026 would be an owner who had an analysis carried out before the sale, which was positive, but omitted this report in the data room of the sales platform. In such a case, the disclaimer is void and the seller must pay for the restructuring costs.

However, it is extremely difficult to prove malice in practice. A seller does not have to explain potential risks “out in the blue” as long as he has no reliable knowledge. He can rely on the buyer to carry out due diligence himself on a property from the 1970s. Only if the buyer explicitly asks about asbestos and the seller guarantees the absence of harmful substances against his better knowledge, is there an assurance that triggers liability even without fault. So anyone who wants to be on the safe side as a seller always answers such questions with reference to the year of construction and their own ignorance.

The buyer's duty of care in 2026

In the current market environment, expectations of buyers have changed massively. According to many experts, anyone who purchases a property built before 1990 in 2026 without commissioning their own pollutant report is acting negligently. Since the risk of asbestos in buildings of this period is now part of “general knowledge,” a buyer can hardly claim that he was surprised by the discovery. When granting mortgages for older properties, many banks now proactively require a GEAK plus or a pollutant check in order to check the value of the security.

This development indirectly relieves the seller. The more obvious a potential risk is due to the age of a property, the less there can be talk of a “hidden” defect. Thorough buyer due diligence today includes budgeting for sampling by specialized laboratories. If this is not done, the court usually assumes that the buyer has accepted the condition of the property “as is.” The seller's legal risk is therefore limited almost exclusively to cases of active manipulation or concealment of existing reports.

Energy-related renovations and the VVEA regulations

A new aspect of the liability discussion in 2026 is the stricter cantonal building regulations and the Waste Handling Ordinance (VVEA). With every major renovation, the client is now required to test the affected components for pollutants. If a seller converted himself shortly before the sale and failed to comply with legal investigation obligations, this could be regarded as an indication of misconduct giving rise to liability. If asbestos waste is illegally disposed of or covered up, there are not only civil claims but also criminal consequences.

For buyers, this means that they should have the appropriate disposal certificates and inspection reports shown to them for newly renovated old buildings. If these documents are missing, extreme caution is required. The seller, in turn, should make transparent in the sales documents which areas were renovated and whether pollutant controls took place. This transparency is the best protection against subsequent recourse claims, as it gives the buyer the basis for an informed purchase decision and nips the allegation of concealment in the bud.

Conclusion: Transparency protects both parties

Is the seller liable for asbestos in case of ignorance? No, usually not, provided that the contract is drawn up correctly. In Swiss tenancy and real estate law of 2026, the buyer's personal responsibility for old buildings remains central. A seller is well advised not to give guarantees that he cannot keep and instead openly point out the year of construction and the associated uncertainties.

In summary, it can be stated that a clean warranty exclusion in the purchase contract is life insurance for the seller against unforeseeable pollutant costs. For buyers, investing in professional asbestos screening before purchase is the only way to avoid unpleasant financial surprises. Anyone who follows the rules of owner due diligence and communicates objectively based on the facts minimizes the risk of lengthy legal disputes after handing over the keys.

glossary

• Malicious deception: The deliberate concealment of a defect in order to influence the conclusion of the contract, which removes the disclaimer.
• Asbestos screening: A technical examination of material samples by a specialist laboratory to determine pollutant loads.
• Due diligence: The due care with which a buyer checks a property for legal, technical and ecological risks before purchasing it.
• VVEA: The Ordinance on Waste Traffic, which, among other things, regulates the obligation to inspect construction activities.
• Disclaimer of warranties: A contractual agreement that largely excludes the seller's liability for defects in the property.