Ondsauna Balneum Vaporarium by Taro Shimokawa is a highly esteemed winner of the very prestigious 2025 Praemium A' Design Award Aeneum in Architectura Competition Category.
AesArchitectura· 2025
Ondsauna Balneum Vaporarium
Client: Ondpark
Praemium A' Design Award Aeneum Winner in Architectura Category
Verified Award Winner
Verify Award Status for #165443The Design
About Ondsauna Balneum Vaporarium
Ondsauna est aedificium balnei vaporarii intra silvam positum. Parietes exteriores verticales circa cellam balnei congregantur, ascensum arborum referentes. Semita spiralis ad locum quietis in tecto ducit. Aditus 250 millimetra supra terram sedet, tabulatum mersionis frigidae ad 1000 millimetra et tectum ad 3250 millimetra, ita ut motus a balneo vaporario ad mersionem frigidam ad aerem apertum verticalis sit. Forma irregularis polygonalis et subsellia angulis obtusis instructa aciem oculorum dirigunt et visitatoribus optionem gradus commercii praebent.
The Recognition
About the Praemium A' Design Award Aeneum
Ondsauna Balneum Vaporarium victor est Praemii A' Design Award Aeneum, honoris multum aestimati formis egregiis, creandi ingenio, sollertia et acumine insignibus dati. Victores Aenei opera perita et mire creandi sunt, quae experientiam, imaginationem et solertiam auctorum suorum confirmant. Exspectatur Ondsauna Balneum Vaporarium rem multum aestimatam, admiratam et carissimam, notabiliter professionalem et novam fore. Haec forma Aeneo victa optimas consuetudines artis, scientiae, formandi rationis et technologiae amplectitur et in cura minutiarum excellit. Ondsauna Balneum Vaporarium necessitates egregie explet, cupiditates tangit, sensus capit et curiositatem allicit.
Behind the Design
Press Kit
Credits, team members and technical details provided by the designer.
- Unique Properties
- Trees grow endlessly upward, a concept reflected in the vertical exterior walls clustered around the sauna room. A spiraling path leads upward to a rooftop relaxation space, mirroring the building's form. The sauna entrance is at GL+250, the cold plunge deck at GL+1000, and the rooftop at GL+3250, so the transition from sauna to cold plunge to open air follows a vertical flow. Viewing the forest at treetop height allows one to share in its growth rhythm.
- Dimensions & Packaging
- The irregular plan was chosen to allow the passage and expansion of the line of sight and to adjust the degree of intimacy, which was rationally solved by the 150mm CLT floor slab. The elimination of beams has eliminated non-perpendicular joints in the structure, contributing to labor savings in site work. The rational walls of the scale module are discretely assembled and the CLT slab connects them. This structural form itself can be described as a sociopetal structure.
- Production Technology
- An irregular polygonal floor plan guides sightlines, creating varied scenic views. Research shows conversations are twice as frequent at 90 degrees versus side-by-side. Here, strangers sit together, so we chose obtuse-angled benches to balance interaction and privacy, encouraging conversation without intrusion. Varied seating allows for different levels of interaction, while the overall arrangement around a fire fosters a shared experience.
- Inspiration
- In a sauna, strangers sit nearly naked in close proximity, creating potential intimacy. Yet in Japan, public saunas haven’t fostered this sense of community. By aligning with Japan’s unique sense of closeness, we aim to create a sociopetal space, encouraging shared understanding without forced intimacy. “Non-intrusive” walls balance connection and separation; their verticality resonates with the forest, while their spacing draws nature in and modulates closeness among neighbors.
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