charred cedar facade enfolds kiln-inspired sauna in japan

Ujizono Architects + bench Craft a Kiln-Inspired Sauna in Kasama

Ujizono Architects has completed Kasamabi Sauna in Kasama City, Japan, a region historically recognized for Kasama ware and ceramics production. The sauna facility is situated within a mixed urban context that includes ceramics schools, art museums, golf grounds, and densely arranged residential buildings. As a program requiring privacy, the site is treated as an enclosed condition bordered by surrounding structures and open fields.

The project considers architecture as a combination of places for lingering and places for circulation, aligning these with areas that preserve cultural context and areas that introduce movement. Its overall concept references the climbing kilns dispersed throughout Kasama, using them as a formal and spatial model to connect the building to its setting. The design allows air and people to move through the spaces while also creating points of pause.

The exterior walls are finished in charred cedar, and the building is topped with a single-sloped roof constructed from flat-laid metal sheets. The roof pitch follows a locally prevalent 3:5 proportion, further linking the design to regional construction practices. An approach path of Inada stone gravel surrounds the structure, establishing a visual boundary for the site. Approach steps in black concrete create continuity between the charred cedar facade and the stone paving.

all images by Yosuke Ohtake

Natural Elements Shape Kasamabi Sauna’s Interior Experience

Inside, the plan integrates horizontal circulation routes and vertical axes, organizing the changing rooms, indoor air bath, and toilets/showers. The arrangement produces a clear layout in which the sauna is visible upon entering from the approach path. The open-air bathing area includes a square atrium that shields views from the adjacent hillside while permitting wind and daylight to enter. On either side of the sauna, a cold plunge pool and a warm bath are symmetrically positioned. A ceramic bathtub beneath the stairs uses well water, ensuring stable year-round temperatures for the cold bath.

The design incorporates natural elements through the light admitted by the atrium, the presence of well water, and the flow of outdoor air within the open bathing zones. These features are paired with the flame of the wood stove, establishing sensory conditions distinct from the surrounding urban environment. Similar to the spatial sequence of a tea house, the building introduces a linear axis that leads toward the sauna, framing the transition from warming to cooling zones.

Through the kiln-inspired roof form, material palette, and spatial organization, Kasamabi Sauna by Kyoto-based firm, Ujizono Architects and interior design practice bench, aims to create a unified architectural environment that aligns with its regional context and facilitates a clear, structured experience for users.

Kasamabi Sauna sits within Kasama City’s mixed cultural and residential context

charred cedar cladding defines the building’s exterior expression

black concrete stairs echo the tones of the charred cedar facade

the project references the region’s long history of Kasama ware and ceramics

interior circulation is organized through horizontal paths and vertical axes

a square atrium brings daylight and airflow into the open-air bath area

the atrium shields views from the hillside while maintaining openness

natural elements, light, air, and water, shape the interior atmosphere

the kiln-inspired form and material palette create a unified architectural environment

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project info:

name: Kasamabi Sauna
architect: Ujizono Architects | @ujizono_architects

interior designers: Shota Ueno – bench | @benchdesign_team

location: Kasama City, Ibaraki, Japan

area: 81 sqm

photographer: Yosuke Ohtake | @yosukeohtake_archiphoto

designboom has received this project from our DIY submissions feature, where we welcome our readers to submit their own work for publication. see more project submissions from our readers here.

edited by: christina vergopoulou | designboom