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Garden sauna in the canton of Solothurn: do you need a building permit?
Which rules apply to an outdoor sauna in the canton of Solothurn, which sizes are possible without a permit and how to proceed.
Updated: September 2026 · independent guide, sources linked
In short
Usually yes. Only unheated small buildings may be put up without a permit – a sauna is heated and therefore doesn't qualify.
The rule in the canton of Solothurn
Single unheated buildings with up to 10 m² covered area (including roof overhangs) and 2.50 m facade height, neither inhabited nor used commercially (§ 3ter para. 1 let. b Cantonal Building Ordinance, in force since 1 October 2024).
What this means for your sauna
A sauna – barrel or cabin, wood or electric – is a heated building. It therefore doesn't fall under the exemption, even if it is smaller than the limit. Expect to file a building application and allow time for it.
Which garden sauna suits the canton of Solothurn?
Whether you need a permit depends a lot on the design and the heater. A compact barrel sauna is smaller than a sauna cabin with a changing room, and a mobile sauna on wheels raises questions of its own. A wood-burning heater adds a chimney and firing rules – see the comparison in Wood or electric heater.
Budget for permit fees and documents (cost of an outdoor sauna) and check boundary distance and ground early (location & foundation).
Living near the cantonal border? Compare with the neighbouring cantons: Aargau and Jura.
For sauna dealers and landscapers in the canton of Solothurn: SEO in the canton of Solothurn.
Procedure and responsible authority
The responsible authority is usually your municipality. Many cantons have a simplified procedure (notification) for minor projects; otherwise the ordinary procedure with public notice applies.
Step by step
Note the dimensions
External dimensions including roof and chimney, heater type, planned location and distance to the boundary.
Check the zone
On the cantonal geoportal or at the municipality: is the plot in a core or protected zone?
Ask the building office
A short enquiry with a sketch and product sheet tells you whether and which procedure applies.
Paperwork
Good suppliers provide plans and data sheets you can use directly for the application.
Important: this page summarises the rules in plain language and does not replace information from the responsible authority. The legal texts in force and your municipality's decision are binding; municipalities may have stricter rules. Updated: September 2026.
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