Swiss second-home law
Wellness, fitness and leisure areas may count as principal usable floor area
Federal Supreme Court judgment 1C_317/2025 and 1C_319/2025 of 11 August 2026
Decision at a glance
In its judgment 1C_317/2025 and 1C_319/2025 of 11 August 2026, the Swiss Federal Supreme Court clarified a key issue in Swiss second-home law. Wellness, spa, pool, jacuzzi, sauna, fitness and games areas may qualify as principal usable floor area. This may materially restrict the expansion capacity that remains available without a second-home use restriction.
The ruling is particularly relevant to owners, buyers, sellers, developers and investors in holiday and second homes located in municipalities where second homes exceed 20 percent of the housing stock.
Legal framework
An old-law home is generally a dwelling that lawfully existed or had been finally permitted on 11 March 2012. Within building zones, old-law homes may be renovated, converted, demolished and rebuilt. Their principal usable floor area may, however, only be expanded without a new use restriction by up to 30 percent of the principal usable floor area existing on 11 March 2012.
Maximum unrestricted second-home floor area = principal usable floor area on 11 March 2012 × 1.30
Area exceeding that threshold is only permissible if it is declared as a primary residence or qualifying tourist-managed accommodation and the restriction is recorded in the land register.
What the Court decided
The case concerned a chalet with two apartments, a wellness area with swimming pool and jacuzzi, sauna, fitness room, changing and shower facilities, and a games room. The owners and the municipality classified these spaces as ancillary areas. The Federal Supreme Court rejected that approach.
The Court focused on the rooms’ function for residential use, comfort and recreation, their actual design and their suitability for prolonged occupation. Such spaces cannot simply be equated with typical ancillary rooms such as storage rooms, cellars, laundry rooms, garages or technical rooms.
Private villas and single-family homes
The decision is not limited to shared facilities or multi-unit buildings. The Court expressly stated that shared use was not decisive. The same approach may therefore apply to private villas and single-family homes.
A privately used pool, spa, gym, home cinema, games room or high-quality hobby and leisure area may count as principal usable floor area where it objectively serves a residential and recreational function and is designed for prolonged occupation.
Relevant practical factors
The plan label or basement location alone is not decisive. Relevant factors include size, ceiling height, natural light, windows or light wells, heating, ventilation, sanitary installations, interior finish, furnishing potential, access to terraces or gardens, designation in the plans and actual use.
Consequences for new and pending projects
For new construction, renovation, conversion, extension and replacement-building projects, total principal usable floor area must be calculated carefully and in accordance with the applicable SIA standards. Wellness, fitness and leisure areas must be counted where they serve a residential and long-stay function.
Example: if the home had 200 m² of principal usable floor area on 11 March 2012, the unrestricted second-home limit is generally 260 m². A new 70 m² wellness area and 40 m² games room may therefore not only consume but exceed the 60 m² expansion allowance.
The judgment is not a statutory amendment; it is a binding interpretation of existing law. It must be applied to applications not yet decided at first instance and, in principle, to permits and appeal proceedings that are not yet final.
Existing permits and later amendments
A final building permit is not automatically revoked or subjected to a new second-home restriction because of the judgment. Construction lawfully approved and completed in accordance with the approved plans remains protected in principle.
However, the finality of a permit extends only to the approved project: its plans, areas, designated uses, permit conditions and any land-register restrictions. It does not automatically authorise material departures or additional residential, wellness or leisure areas.
An amendment application or a new building application may therefore be required where wellness, fitness or games rooms are enlarged; cellars or ancillary rooms are converted into long-stay spaces; a sauna, jacuzzi, indoor pool or gym is added; or originally open, unheated or non-residential areas are enclosed, glazed, heated or repurposed.
Such amendments must be assessed under Article 11 of the Second Homes Act as now interpreted by the Federal Supreme Court. If the additional space serves a residential function and is intended for prolonged occupation, it will normally count as principal usable floor area and may reduce or exhaust the remaining 30 percent allowance.
Valuation and transactions
The ruling may affect valuations, financing, price negotiations and due diligence. It does not reduce the amenity value of a high-quality wellness installation. A pool, spa or gym may increase the appeal of a holiday property.
The issue is the legal value of the development reserve. A zoning reserve is not necessarily the same as unrestricted second-home development capacity. If wellness, leisure or long-stay areas consume the latter, the freely usable future potential may be reduced or eliminated.
We would be pleased to assist with any questions or with a property-specific review:
Source: Swiss Federal Supreme Court, judgment 1C_317/2025 and 1C_319/2025 of 11 August 2026; Article 11 of the Swiss Second Homes Act.
Disclaimer: This newsletter provides general information only and does not constitute legal advice. Every property and project requires an individual review of the approved plans, the lawful historical condition as at 11 March 2012, the building permit, the land register, the applicable cantonal and municipal rules, and the intended use of the relevant rooms.
