Construction Defect Liability in Switzerland: the 2026 Right to Rectification and What Owners, Contractors and Insurers Must Do

Last reviewed: 15 May 2026

Construction defect liability in Switzerland underwent its most significant statutory overhaul in decades when the partial revision of the Code of Obligations (CO) took effect on 1 January 2026, introducing a mandatory right to rectification for works contracts and reshaping the remedies available to building owners, developers and purchasers. The reform, driven by longstanding criticism that the previous regime left owners with an unsatisfactory choice between price reduction and contract rescission, now requires contractors to be given the opportunity to cure defects before other remedies may be pursued. Alongside the new rectification right, the revision adjusts defect-notice obligations, realigns limitation periods, and creates knock-on consequences for insurance coverage, subcontractor indemnities and standard-form contracts such as SIA 118.

This guide explains the changes in practical terms, provides compliance checklists and sample clauses, and identifies the priority actions that owners, contractors and insurers should take now. For jurisdiction-specific advice, find a Swiss lawyer through the Global Law Experts directory.

Executive summary, what changed and what to do now

The 2026 partial revision of warranty and defect-liability rules under the Swiss Code of Obligations (CO) applies to all works contracts (and certain sales contracts) governed by Swiss law from 1 January 2026 onward. The reform was enacted by the Federal Assembly following broad industry consultation and is confirmed by the Chambers Practice Guides country update for Switzerland and the International Bar Association’s Construction Law International report of March 2026.

The key changes at a glance:

• Mandatory right to rectification. The contractor now has a statutory right, and obligation, to offer substitute performance (rectification or repair) before the owner may pursue alternative remedies such as price reduction or rescission (new Art. 368 para. 2^bis CO).
• Adjusted defect-notice obligations. The rules governing immediate notice for obvious defects and discovery-triggered notice for hidden defects have been tightened, with clearer requirements for written, substantiated notifications.
• Realigned limitation periods. The interplay between the two-year and five-year warranty/limitation windows has been recalibrated to reflect the rectification procedure and to protect owners who discover hidden defects late.
• Expanded remedy hierarchy. Remedies now follow a structured sequence: rectification first, then price reduction, rescission (for serious defects) or damages, each with specific preconditions.
• Insurance and indemnity implications. Policies written under the previous regime may not automatically respond to mandatory rectification costs, creating gaps that require immediate review.
• SIA 118 interface. Contracts incorporating SIA 118 must be reviewed against the new CO provisions to ensure complaint periods and remedy sequences do not conflict with mandatory law.

Three priority actions:

• Owners and developers: Review all pending and new construction contracts to ensure defect-notice clauses comply with the revised CO and that the mandatory rectification procedure is reflected in the works contract.
• Contractors and subcontractors: Update internal defect-response procedures, train site teams on rectification timelines, and review downstream supplier indemnities to ensure back-to-back coverage.
• Insurers and brokers: Audit existing construction-liability and professional-indemnity policies against the new rectification obligation; adjust policy wordings, notification triggers and subrogation clauses.

Legal framework: the 2026 revision to construction contract law in Switzerland

The partial revision amends the warranty provisions of the Swiss Code of Obligations applicable to works contracts (Art. 363–379 CO) and, in parallel, adjusts certain rules governing sales-contract warranties (Art. 197 ff. CO) to harmonise the two regimes. The reform entered into force on 1 January 2026 by Federal Council decree, as confirmed by Fedlex. The legislative purpose, according to the Federal Council’s explanatory report (Botschaft), was threefold: to give contractors a fair opportunity to cure defects before facing harsher remedies; to strengthen the owner’s position by formalising notice and evidence obligations; and to modernise limitation rules that had become outdated.

Key new provisions, article-by-article overview

Interaction with SIA standards and sales warranty rules

SIA 118, the General Conditions for Construction Works issued by the Swiss Society of Engineers and Architects (SIA), remains the dominant standard-form contract in Swiss construction. SIA 118 already contained its own complaint periods (typically a two-year guarantee period with specific notice requirements). Industry observers expect that the mandatory character of Art. 368 para. 2bis CO will override any SIA 118 provision that permits the owner to bypass rectification and proceed directly to price reduction. Parties using SIA 118 should therefore insert a supplementary clause confirming compliance with the revised CO remedy hierarchy. The parallel amendments to the sales-contract warranty provisions (Art. 197 ff.

CO) introduce a similar right to substitute performance for sellers, which is relevant where building components are purchased under a standalone supply agreement rather than a works contract.

Who is liable? Allocation of construction defect liability in Switzerland

Under Swiss construction contract law, the primary contractor owes the owner a works contract obligation to deliver a defect-free result. This fundamental principle is unchanged by the 2026 revision. Contractor liability under Art. 368 CO is contractual and strict in character, the owner need not prove fault, only the existence of a defect and timely notification. Where multiple contractors are engaged (general contractor plus subcontractors), the general contractor bears primary liability towards the owner and must manage its own downstream claims.

Downstream supplier and subcontractor claims

The 2026 revision has a cascading effect on subcontractor liability. Because the general contractor must now first offer rectification to the owner, it needs corresponding back-to-back obligations from its subcontractors and suppliers. Industry observers expect a market-wide push to update subcontract templates so that the subcontractor’s rectification obligation mirrors the general contractor’s duty under the revised CO. Without such alignment, the general contractor risks being unable to pass through rectification costs within the statutory limitation periods.

Joint and several liability scenarios

Where a defect is attributable to multiple parties, for example, a design professional and a contractor, Swiss law permits the owner to claim against either party for the full loss (Art. 50/51 CO, tortious joint liability). The 2026 changes do not alter these rules, but they do add a procedural step: before pursuing damages from either party, the owner must first allow the party responsible for the defective work to attempt rectification. Where the defect results from a defective product incorporated into the building, the owner may also pursue a product-liability claim against the manufacturer under the Swiss Product Liability Act (PrHG), which operates independently of the works-contract regime.

The mandatory right to rectification (substitute performance)

Art. 368 para. 2^bis CO introduces a mandatory right to rectification: the contractor must be given a reasonable opportunity to cure any notified defect before the owner may exercise alternative remedies. This provision, confirmed by the Schellenberg Wittmer firm analysis, represents the centrepiece of the 2026 reform. Under the prior regime, the owner could move directly to price reduction or rescission without offering the contractor the chance to repair, a result widely criticised as economically wasteful.

When rectification is mandatory vs discretionary

Rectification is mandatory in all cases unless one of the following exceptions applies:

• Disproportionate cost. If the cost of rectification is grossly disproportionate to the benefit gained by the owner, the contractor may refuse and the owner proceeds to other remedies.
• Impossibility. If the defect cannot physically be rectified without dismantling or destroying the entire work.
• Unreasonableness for the owner. If the owner can demonstrate that further work by the contractor is unreasonable, for example, where the contractor has demonstrated persistent incompetence or the relationship has irretrievably broken down.
• Contractor refusal or failure. If the contractor expressly refuses to rectify or does not commence rectification within the reasonable period set by the owner.

Outside these exceptions, the owner who bypasses rectification and directly claims price reduction or damages risks having the claim rejected or reduced by the court.

Practical checklist for offering rectification

Contractors should adopt a documented rectification protocol to comply with the new builders liability obligations under the 2026 regime:

1. Acknowledge receipt of the defect notice in writing within 5 business days.
2. Inspect the defect jointly with the owner (or the owner’s representative) and document findings with photographs and a signed inspection report.
3. Submit a rectification proposal specifying the method, timeline, estimated cost (borne by the contractor) and any access requirements.
4. Agree a reasonable rectification period in writing, industry practice suggests 30 to 90 days depending on defect severity.
5. Execute the rectification and request the owner’s sign-off upon completion.
6. Reserve downstream claims against subcontractors or suppliers within the applicable limitation period.

Owners, conversely, should keep a parallel record: the defect notice, the deadline granted, the contractor’s response and the result of the rectification attempt. This documentation will be decisive if the matter proceeds to litigation or arbitration.

Defect notice period in Switzerland: limitation rules and practical workflow

Under the revised Art. 367 CO, the owner must inspect the work upon delivery and notify any apparent defects without delay; hidden defects must be reported immediately upon discovery, subject to a five-year overall limitation period for immovable works (Art. 371 CO). The Homburger insight on modified warranty rights confirms this framework and notes the practical importance of written, substantiated notifications.

Evidence standards for notices

A defect notice that preserves rights should contain the following elements:

• Date of discovery (or date of delivery inspection for apparent defects).
• Precise description of the defect, its location and visible manifestation.
• Photographic or video evidence taken at the time of discovery.
• Express reservation of all warranty rights under the CO and the applicable contract.
• A deadline for the contractor to respond and propose rectification (typically 10–14 days for the response; 30–90 days for the repair itself).
• Delivery method: registered post or other traceable means with proof of receipt.

Sample defect-notice template

The following is illustrative only and should be adapted to the specific contract and circumstances with the assistance of qualified counsel.

[Registered post / Email with read-receipt]

“Dear [Contractor],

We refer to Works Contract dated [date], Project [name/number]. During [inspection on delivery / routine use on [date]], we identified the following defect(s): [description, location, reference to plans/specifications]. Photographic evidence is enclosed.

Pursuant to Art. 367 and Art. 368 CO (as revised), we hereby formally notify the above defect(s) and reserve all our warranty rights, including rectification, price reduction, rescission and damages. We invite you to inspect the defect(s) within [10] days and to submit a rectification proposal within [14] days of inspection. If no proposal is received, or if rectification is not completed within a reasonable period, we reserve the right to pursue alternative remedies without further notice.

Yours faithfully, [Owner / Owner’s representative]”

Remedies explained: repair, replacement, price reduction, rescission and damages

The 2026 revision establishes a clear hierarchy of warranty rights for construction in Switzerland. Under the revised Art. 368 CO, the remedy sequence operates as follows:

1. Rectification (substitute performance), the primary remedy. The contractor must be given the chance to cure.
2. Price reduction, available if rectification fails, is refused, or falls within one of the exceptions noted above.
3. Rescission (Wandelung), available only for serious defects that render the work essentially unusable or fundamentally impair the purpose of the contract.
4. Damages, available in parallel with rectification (for consequential loss) or as a standalone claim where the owner has suffered loss beyond the defect itself (e.g., business interruption, alternative accommodation costs).

When to seek damages instead of rectification

Damages become the more strategic remedy where the defect has caused consequential losses that rectification alone will not compensate, for instance, rental income lost during a prolonged repair period, or costs of emergency temporary works. Owners should be aware that damages claims require proof of fault (Art. 368 para. 1 CO read with Art. 97 CO), whereas rectification and price reduction do not. Early engagement of a forensic quantity surveyor or construction expert is advisable where damage quantum is likely to be contested.

Set-off and reduction calculations

Price reduction under Swiss law is calculated by comparing the value of the work as delivered (with the defect) against the value it would have had if delivered defect-free. In practice, courts often use the estimated cost of cure as a proxy. Contractors should be alert to owner claims for price reduction that exceed the actual rectification cost, a point frequently disputed in Swiss construction litigation. The likely practical effect of the 2026 reform will be to make such disputes less common, because rectification must now be attempted first, providing a concrete cost reference.

Insurer and indemnity considerations: construction defect liability and coverage

The 2026 reform has direct implications for construction-liability insurers. Policies written before the revision may not explicitly cover the contractor’s cost of mandatory rectification, because many older wordings treat “repair” as an excluded betterment cost rather than an insured liability event. Insurers and brokers should audit all active construction-related policies immediately.

Subrogation and product-component insurers

Where a contractor’s insurer covers the cost of rectification, the insurer may subrogate against the subcontractor or product manufacturer whose defective workmanship or component caused the defect. The 2026 changes strengthen the subrogation pathway, because the mandatory rectification procedure generates documented evidence of the defect, the attempted cure and the resulting cost, all of which facilitate downstream recovery. Product-component insurers (e.g., fire-protection system manufacturers’ liability policies) should anticipate increased subrogation activity and ensure their own policies contain adequate reserves.

Insurer notification and reservation of rights

Best practice for claims handling under the new regime includes the following steps:

• Immediate notification to the insurer upon receipt of any defect notice from the owner, do not wait for the rectification outcome.
• Reservation of rights letter issued by the insurer within 14 days, confirming coverage investigation is ongoing.
• Joint inspection involving the insurer’s appointed expert alongside the contractor and owner.
• Coordination between the contractor’s liability insurer and any product-component insurer before rectification is attempted.
• Post-rectification review of costs to confirm they fall within policy coverage and do not constitute excluded betterment.

Contract drafting and risk-transfer: sample clauses for construction defect liability in Switzerland

The 2026 revision requires parties to update both new and existing construction contracts. The following sample clauses illustrate how to integrate the new mandatory provisions. Each clause is annotated with its purpose and enforceability considerations.

Note: Art. 368 para. 2^bis CO is mandatory law and cannot be contractually excluded. Clauses that purport to waive the contractor’s right to rectification, or the owner’s obligation to permit it, are likely unenforceable.

• Clause 1, Defect-notice procedure. “The Owner shall notify the Contractor of any defect in writing within [10] days of discovery, specifying the nature and location of the defect and enclosing supporting evidence. Failure to provide timely notice does not extinguish the Owner’s warranty rights but may affect the assessment of damages.” Purpose: Implements Art. 367 CO. Enforceable provided the notice period is reasonable.
• Clause 2, Mandatory rectification window. “Upon receipt of a defect notice, the Contractor shall inspect the defect within [10] days and submit a rectification proposal within [14] days of inspection. Rectification shall be completed within [60] days unless a longer period is agreed in writing. The Owner shall provide reasonable access.” Purpose: Implements Art. 368 para. 2^bis CO. Enforceable; recommended as a minimum.
• Clause 3, Consequences of failed rectification. “If the Contractor fails to complete rectification within the agreed period, or if the rectification does not cure the defect, the Owner may at its election: (a) demand a price reduction; (b) rescind the contract (for serious defects only); or (c) claim damages, in each case without further notice.” Purpose: Implements Art. 368 para. 3 CO.
• Clause 4, Back-to-back subcontractor rectification. “The Subcontractor’s rectification obligations mirror those of the Contractor under the Main Contract. The Subcontractor shall commence rectification within [5] days of receiving notice from the Contractor.” Purpose: Ensures cascading compliance down the supply chain.
• Clause 5, Insurer cooperation. “Each party shall notify its insurer of any defect claim within [5] business days. The parties shall cooperate to facilitate joint inspections and shall not settle any insured claim without the insurer’s prior written consent.” Purpose: Prevents coverage loss through late notification.
• Clause 6, Limitation and preservation of rights. “Nothing in this Contract reduces or excludes the statutory limitation periods under Art. 371 CO. All warranty rights are cumulative and are in addition to any claims in tort or under the Product Liability Act.” Purpose: Prevents inadvertent exclusion of mandatory limitation rules.

Clauses to avoid

• Any clause purporting to waive the mandatory right to rectification under Art. 368 para. 2^bis CO.
• Clauses that shorten limitation periods below the statutory minimum for immovable works (five years).
• Blanket exclusion of consequential damages, Swiss courts may strike such clauses if they effectively deprive the owner of the benefit of the warranty regime.

Checklist: what to insert in new and existing contracts

• Updated defect-notice clause (written, substantiated, with deadline).
• Mandatory rectification procedure with defined timeline.
• Remedy escalation clause (rectification → reduction → rescission → damages).
• Back-to-back subcontractor/supplier rectification obligations.
• Insurer notification and cooperation clause.
• Express preservation of statutory limitation periods.
• SIA 118 compatibility confirmation (if SIA 118 is incorporated by reference).

Practical litigation and dispute resolution tips

Evidence checklist for proving construction defects

Successful defect claims depend on contemporaneous evidence. The following items should be preserved from the earliest stage:

• Dated photographs and video of the defect in situ, with scale reference.
• Written defect notice with proof of delivery (registered post receipt or email read-receipt).
• Independent expert report, commission a qualified construction expert (court-appointed or party-appointed) to inspect and report before any repair attempt alters the evidence.
• Contractor correspondence, all responses, rectification proposals, access requests and completion confirmations.
• Cost records, invoices, quotations and payment records for the original works and any rectification.
• Contract documents, the works contract, SIA 118 (if applicable), specifications, drawings and any amendments.

Sample timeline for escalation

1. Day 0: Defect discovered, photograph, document, notify contractor.
2. Day 10: Contractor inspects; joint report signed.
3. Day 24: Contractor submits rectification proposal.
4. Day 25–84: Rectification period (60 days standard).
5. Day 85: Owner inspects completed rectification; if satisfactory, matter closed.
6. Day 85+: If rectification fails or is refused, owner issues written notice of alternative remedy election (price reduction / damages / rescission) and refers to conciliation or arbitration.

Practice scenario: An owner of a residential development discovers water ingress through a flat-roof membrane 18 months after acceptance. The owner sends a written defect notice with photographs and grants the contractor 60 days to rectify. The contractor attempts a patch repair, but the ingress recurs within two weeks. The owner commissions an independent expert report confirming a systemic membrane installation defect. Having satisfied the mandatory rectification requirement, the owner now elects to claim damages covering full membrane replacement, consequential water-damage repair and alternative accommodation costs for affected tenants. The documented rectification attempt, and its documented failure, provides compelling evidence of the defect’s severity and the owner’s reasonableness.

Comparison table: reporting obligations and defect notice deadlines by entity type

Sources

1. Swiss Code of Obligations (Fedlex), works contract and warranty provisions
2. Schellenberg Wittmer, Partial Revision of Defect Warranty Rights
3. Walder Wyss, Newsletter on Construction Defects: Partial Revision of Warranty Law
4. Homburger, Modified Warranty Rights for Construction Defects
5. International Bar Association, Construction Law International, March 2026 Switzerland Update
6. Chambers Practice Guides, Construction Law (Switzerland)
7. SIA (Swiss Society of Engineers and Architects), SIA 118 Standards
8. UBS, The Builder’s Rights (Client Guide)
9. BMapp, Construction Defects Liability: Procedure and Notification of Defects Template