A Sauna for the People

The history of the Trosten Sauna began eight years before it opened. In 2016, the nonprofit Oslo Badstu­forening was founded by an unusual mix of artists and diplo­mats from the Norwe­gian Ministry of Foreign Affairs’ ice-swim­ming club. The members built their first sauna, Måken, them­selves using drift­wood they had found in Bjør­vika.

That makes­hift raft gave rise to a move­ment. Saunas and ice baths became incre­asingly popular in Oslo, and Måken grew into an entire floa­ting sauna village. The Trosten Sauna is an archi­tec­tu­rally ambi­tious evolu­tion of that concept and, when it opened in 2024, was already the association’s 19th sauna. In 2023 alone, the Oslo Badstu­forening had around 15,000 members and 250,000 visits. To this day, its motto remains delightfully straight­for­ward: “Badstue til folket”—sauna for the people.

From an urban plan­ning perspec­tive, this deve­lo­p­ment is also part of a larger context. The Sauna Village is located at the mouth of the Aker­selva River and is part of the trans­for­ma­tion of Oslo’s former container port. Along the fjord, a roughly seven-kilo­meter-long harbor prome­nade has been created, featuring paths for walking, running, and biking, as well as recrea­tional areas, beaches, and swim­ming plat­forms. The saunas extend this public space out onto the water.

For Trosten, estudio Herreros returned to a very fami­liar loca­tion. The Spanish firm had already desi­gned the Munch Museum, which opened in 2021, just a few meters away. During cons­truc­tion, the small sauna was ther­e­fore nick­named “Munch’s baby.”

The compa­rison holds true at least in terms of simi­la­rity, though less so in terms of scale. Trosten is a small but deli­bera­tely distinc­tive buil­ding with a striking silhou­ette and a vibrant green or turquoise shim­me­ring aluminum exte­rior. It can accom­mo­date up to 24 people inside.

The complex also features its own swim­ming terrace with direct access to the fjord and an outdoor amphi­theater that seats about 50 people. This amphi­theater remains open to the public, making Trosten a gathe­ring place by the water even when the sauna is not in opera­tion. The tiered seating area thus extends the sauna’s social func­tion to the outdoors and creates a small audi­to­rium with the fjord and the city as a back­drop.

Trosten was Norway’s first floa­ting sauna to be desi­gned enti­rely in accordance with the prin­ci­ples of universal design. The sauna room can accom­mo­date two wheel­chairs at the same time. To make room for them, parts of the lower bench can be slid in.

However, that alone would not solve the actual problem with a sauna. Heat rises, which is why the higher benches are the hottest spots. For people who have to stay on the lower level, a formally acces­sible sauna would ther­e­fore be far from equally usable.

Elec­tric fans circu­late the warm air in the room and ensure adequate tempe­ra­tures even in the lower areas. In addi­tion, there are heated exte­rior surfaces, handrails, and an auto­matic door opener. The front row of the amphi­theater is also acces­sible to wheel­chair users. Thus, acces­si­bi­lity here extends beyond mere access routes and circu­la­tion areas to the very func­tion of the buil­ding itself.

The cons­truc­tion process also followed an unusual sequence. The wooden struc­ture was first assem­bled in a dry dock outside central Oslo and then placed on a prefa­bri­cated floa­ting concrete plat­form. The facade and inte­rior finishes were completed there. Only then was the entire struc­ture towed across the water to its loca­tion at Sukk­er­biten and anchored there. This allowed the already heavily used sauna village to continue opera­ting largely undis­turbed during the cons­truc­tion phase.

The supporting struc­ture is made of certi­fied wood. Large-format terrazzo slabs are used in the inte­rior, and their mass also helps to store heat. The exte­rior clad­ding is made of recy­cled, anodized aluminum. The profiles used are parti­cu­larly inte­res­ting: they were origi­nally deve­loped for truck side­wall systems and have been repur­posed for the Trosten Sauna.

The name, too, reflects a connec­tion between the archi­tects’ origins and their loca­tion. “Trosten” is the Norwe­gian word for thrush. This migra­tory bird travels between the Iberian Penin­sula and Nort­hern Europe, symbo­li­zing the connec­tion between the Spanish estudio Herreros and Oslo. Its annual return is tradi­tio­nally considered a good omen in Norway.