Swiss law governs construction work differently from French law. Two differences often catch people out: there is no ten-year structural warranty, and an overrun estimate does not always bind the client. Knowing these rules before signing avoids most disputes.

Estimate or fixed price: a decisive distinction

Article 373 of the Code of Obligations covers fixed prices: once agreed, the contractor must complete the work for that amount, even if it proves more demanding than expected. Article 375 covers the approximate estimate.

If an approximate estimate is exceeded disproportionately through no fault of the client, the client may withdraw from the contract. Whether an overrun is disproportionate is assessed case by case, depending on the nature of the work and the circumstances: the law sets no percentage.

Checking the company before signing

• UID number in CHE-xxx.xxx.xxx format, free to check on the federal register
• Entry in the cantonal commercial register, with exact company name and authorised signatories
• Valid certificate of business liability insurance
• SUVA affiliation or equivalent from the first employee onwards
• Professional qualification: federal certificate, diploma or master craftsman title depending on the trade
• Debt collection register extract, an indicator of the company's financial health

There is no ten-year structural warranty in Switzerland

This is a common misunderstanding among clients from France or those working with cross-border companies. The ten-year warranty comes from the French Civil Code and has no Swiss equivalent.

The Swiss system rests on article 371 CO: defects in immovable works become time-barred five years after acceptance. Many contracts also refer to SIA standard 118, which provides a two-year warranty period during which any defect may be reported, followed by up to five years for hidden defects.

Notice of defects: the rule changed in 2026

A revision of the Code of Obligations came into force on 1 January 2026 and substantially changes this rule. Previously the client had to report defects immediately, a deadline the courts set at just a few days. Now, for immovable works, sixty days apply from delivery or from discovery of the defect.

• The sixty-day period is mandatory: no contract may shorten it
• Notice must be given in writing
• It covers both apparent and hidden defects, the latter running from discovery
• A right to free rectification becomes mandatory for new buildings or those under two years old
• The new rules apply only to contracts concluded from 1 January 2026; earlier contracts remain under the previous law
• For movable works not integrated into a building, the duty to report immediately remains

Deposits, VAT and right of withdrawal

Swiss practice puts the deposit at around one third of the amount, with staged payments following progress. No statute sets a ceiling, but a demand for full payment before work begins is never justified.

Swiss VAT has stood at 8.1 % since 2024. The quote must clearly state whether amounts are exclusive or inclusive of VAT, along with the company's VAT number where applicable.

For contracts concluded at your home, workplace or through doorstep selling, articles 40a et seq. CO grant a fourteen-day right of withdrawal where the service exceeds one hundred francs. It does not apply if you requested the visit yourself.