Construction Defects Switzerland 2026: 60-Day Rule under CO Art. 370

On 1 January 2026, a mandatory 60-day deadline took effect in Switzerland for written notification of construction defects. The legal basis is the new Art. 370(1bis) of the Swiss Code of Obligations (CO), introduced by parliamentary decision on 20 December 2024 and in force since 1 January 2026. Miss the deadline and you may forfeit your warranty rights.

A common misunderstanding: the 5-year warranty (CO Art. 371) is not a 2026 innovation — it existed well before. What is new in 2026 is, first, the 60-day deadline for written defect notification; second, the mandatory right to repair; and third, the non-derogable nature of the 5-year period.

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Key Takeaways

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What Actually Changed in 2026?

Many property owners read that the 5-year warranty is new. That is not accurate. Here is a clear overview:

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The 60-Day Deadline in Detail

When Does the Deadline Begin?

The 60-day deadline starts differently depending on the type of defect:

• Visible defects (apparent at acceptance): the deadline begins on the day of acceptance
• Hidden defects (only detectable later): the deadline begins on the day you discovered the defect or should have discovered it

The "should have discovered" standard matters. If you ignore damage or could reasonably have noticed it during regular inspection, you cannot claim the clock never started.

What Does "In Writing" Mean?

Oral notifications, text messages or casual site conversations do not constitute valid notice. The notification must be documented in writing:

• Registered mail — recommended (proof of delivery)
• E-mail with read receipt — possible, but less secure
• Site protocol countersigned by both parties — also valid

What Happens If You Miss the Deadline?

If you exceed 60 days, you may forfeit your warranty rights in whole or in part. The contractor can refuse the repair. You would then need to prove that the late notice did not disadvantage the contractor — a difficult standard to meet.

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Procedure When You Discover a Defect (3 Steps)

Step 1: Documentation

Before sending the notice, record the following:

• Photographs and videos with date and time
• Written description: location, type and extent of the defect
• Date of discovery
• Names of potential witnesses
• Copies of the construction contract and acceptance protocol

This documentation is decisive if the contractor disputes your claim.

Step 2: Defect Notice by Registered Mail

Your written defect notice should include:

• Your name and address, and those of the contractor
• Date of the construction contract and acceptance
• Precise description of the defect with location and date of discovery
• Demand for professional, cost-free repair
• Reasonable repair deadline (typically 30 days)
• Reservation of further legal remedies

Step 3: Follow Up

Keep the delivery receipt. Set a calendar reminder for the end of the repair deadline. If the contractor does not respond, engage a construction expert and notify your legal protection insurer.

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Defect Notice Template under CO Art. 370(1bis)

[Your Name and Address]
[Date]

By Registered Mail

[Contractor Company Name]
[Contractor Address]

Subject: Defect Notice under CO Art. 370(1bis)
Construction Project: [Address/Project]
Contract dated [Date] / Acceptance dated [Date]

Dear Sir or Madam,

Pursuant to Art. 370(1bis) of the Swiss Code of Obligations, I hereby notify
you within the legal 60-day deadline of the following defect:

DESCRIPTION OF DEFECT:
- Location: [precise location]
- Type: [description of the defect]
- Discovered on: [Date]
- Effects: [description]

PHOTO DOCUMENTATION:
See attachments: photographs 1 to X dated [Date]

DEMAND:
I request that you repair the above defect professionally and at no cost
by no later than [Date + 30 days].

Should the repair not occur within this deadline, I reserve the right to
arrange substitute performance at your cost and to pursue further legal
remedies.

Kind regards,

[Signature]
[Name]

Attachments:
- Photographs ([number] pieces, with date)
- Copy of construction contract
- Copy of acceptance protocol

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5-Year Warranty: Now Mandatory

The 5-year warranty under CO Art. 371 existed before 2026. New since 2026: it can no longer be reduced to your detriment by contract (CO Art. 371(3) — mandatory law). Previously, contracts could provide shorter periods — that is now void.

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Common Construction Defects and Typical Discovery Periods

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Legal Protection for Homeowners

Construction defects frequently lead to disputes. Legal protection insurance can help:

• Construction legal protection: coverage for disputes with tradespeople or general contractors
• Contract legal protection: for problems around the construction contract
• Lawyer and court costs: covered according to the policy

Note: most insurers only cover disputes that arise after the contract is concluded. Take out the insurance before construction begins — not only when a conflict already exists.

If you are dealing with a defect dispute involving collection or enforcement matters, our article on debt collection and deletion 2026 covers related ground. For property-law changes affecting your construction project, see our guide on noise protection rules 2026.

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Dispute with the Contractor: What to Do?

Engage an Independent Construction Expert

An independent expert can assess the defect objectively, determine the cause and estimate repair costs. This assessment is valuable whether you seek a settlement or proceed to court.

Mediation

Before going to court, mediation is often worth attempting:

• Faster than litigation
• Less expensive
• Amicable solutions possible

Court Proceedings

As a last resort: file a claim, notify your legal protection insurer, engage a lawyer. Cantonal courts hear construction matters; some cantons have specialised chambers.

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5 Tips for Homeowners

1. Review the acceptance protocol carefully — note every visible defect. Items not recorded are harder to claim later.
2. Set a calendar reminder — mark the end of the period (5 years after acceptance) for an annual inspection.
3. Keep the documentation — contracts, protocols, all correspondence — for at least 10 years.
4. Insure before construction begins — legal protection insurance in good time.
5. Engage an expert at acceptance — for larger projects, an independent construction expert spots defects that laypeople miss.

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Glossary

Construction contract (Werkvertrag): contract under which a contractor undertakes to produce a work; governed by CO Art. 363 et seq.

Defect notice (Rügeobliegenheit): the customer's burden to notify discovered defects to the contractor in writing within the deadline; from 2026 governed by CO Art. 370(1bis).

Warranty period: period within which the customer can assert defects; for construction works, 5 years under CO Art. 371.

Right to repair (Nachbesserungsrecht): contractor's right to first remedy discovered defects; mandatory from 2026 for immovable works.

Substitute performance: customer's right, after unsuccessful expiry of the deadline, to have the repair carried out by a third party at the contractor's cost.

Burden (Obliegenheit): duty to notify in writing within the deadline; failure can lead to forfeiture of warranty rights.

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FAQ

What happens if I miss the 60-day deadline?

Your warranty claims can be wholly or partially forfeited. The contractor can refuse the repair. You would need to prove that the late notice did not disadvantage the contractor — a difficult standard to meet. The recommendation: act immediately when you discover a defect.

Did the 5-year warranty exist before 2026?

Yes. The 5-year warranty under CO Art. 371 existed before the legal revision. The change since 1 January 2026 is that this period can no longer be shortened to your detriment by contract. Shorter periods in contracts are now void.

Does the deadline apply to projects already underway?

The new rules apply to contracts concluded after 1 January 2026. For contracts signed before that date, the previous law applies. Check the date of your contract if you are unsure.

Can the contractor contractually exclude the right to repair?

No — since 1 January 2026, the right to free repair of defects is mandatory for immovable works. A contractual exclusion of this right is void. The contractor must be given the opportunity to repair before you take other measures.

Do I have to repair myself and claim the costs?

In principle, the contractor has the right to repair first. Only if the repair is refused, fails or appears unreasonable can you arrange substitute performance — engage a third party and claim the costs from the contractor. Without a prior deadline being set, there is no claim for cost reimbursement.

Which construction works does the 60-day deadline apply to?

It applies to immovable works (buildings, extensions), to movable elements permanently integrated into a building (e.g. built-in kitchens, sanitary installations) and to planning services by architects and engineers, provided these formed the basis of the construction. For simple repairs to movable objects, other CO provisions apply.

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Conclusion

The 2026 legal revision strengthens the position of homeowners — but only if they know and apply the new rules. The 60-day deadline for defect notification is mandatory, must be in writing and runs from the discovery of the defect. Those who act too late lose their right.

Document discovered defects immediately, send the notice by registered mail and set the contractor a reasonable repair deadline. Legal protection insurance offers additional security in case of disputes. For broader insurance context for your property, see our insurance overview or return to the blog index.

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