Client : private
Architect : Takuto Ihara
Program : holiday house
Location : Aso-Ubuyama, Japan
Size : 149 m²
Status : on going

In Japan, many traditional houses with cultural value are gradually being lost as they remain unused and deteriorate over time.
This project transforms a traditional wooden house, built approximately 100 years ago in Aso Ubuyama Village into a private holiday accommodation called “YADOYA”. Surrounded by Mount Aso and the Kuju mountain range, the village is known for its rich natural environment, vast grasslands, hot springs, and abundant spring water. All water used in the house is supplied from Ikeyama Spring, one of Japan’s 100 most famous water sources.
The renovation respects the cultural value of the existing house while restoring its original character, which had been altered over time. The existing timber structure is preserved, while locally sourced Oguni cedar is used for new structural elements and flooring. Traditional materials such as earthen walls, lime plaster, and roof tiles are combined with contemporary construction methods to maintain the simple beauty of Japanese architecture.
The original stone foundation system (ishiba-date) is also retained. Rather than replacing it with a modern concrete foundation, this traditional method is valued for its adaptability to the Japanese climate, allowing natural drainage and airflow beneath the floor while providing flexibility against seismic movement.
By combining local resources, traditional craftsmanship, and contemporary comfort, “YADOYA” aims to create a sustainable form of architectural regeneration, a place where people, culture, and nature can exist together in harmony.

Yadoya Aso-Ubuyama

Client : private
Architect : Takuto Ihara
Program : Single-Family House
Location : Berlin, Germany
Size : 255 m²
Status : on going

This project is an extension and renovation of a house built in the 1930s, located in a residential area on the outskirts of Berlin. The existing house stands on a long and narrow plot, and the main challenge was to maximise the living space for the family while preserving, as much as possible, the existing garden and a pine tree over 100 years old.
The client wished to create a clear contrast between the existing house and the new extension. Therefore, the original street-facing house, including its characteristic roof form, was carefully preserved. The extension was constructed using a prefabricated timber structure combined with straw insulation panels. The existing house is finished with rendered walls that relate to the surrounding buildings, while the extension is clad in charred timber boards, expressing the different periods and construction methods in a straightforward way.
At the same time, the aim was not only to create contrast but also to bring the two parts together as one house. Although different materials are used, both the rendered facade and the charred timber cladding share a vertical expression, creating a common rhythm across the entire facade. The roofs of both the existing house and the extension are finished with zinc, allowing the different roof forms to be unified through a single material and creating a coherent overall silhouette. In addition, a continuous eaves line wrapping around the building connects the existing and new parts, like a straw hat placed over the house, bringing the two volumes together as one unified home.
This idea is also reflected in the internal layout, where an open and continuous circulation route gently connects each space. Views and movement extend from the existing house through the extension and towards the garden and the woodland beyond, creating a spatial experience where architecture and landscape become closely connected.

House K

Client : private
Architect : Takuto Ihara
Program : Small office/apartment
Location : Berlin, Germany
Size : 63 m²
Status : on going

The client has a compact 30 m² commercial unit which he wants to transform into his private workspace. The space consists of two rooms, one facing the street and the other the inner courtyard. With a ceiling height of approximately 4.5m, the groundfloor property offered significant potential for vertical expansion.
The design introduces a new mezzanine level, making full use of the generous ceiling height to expand the usable floor area. While the new floor is divided by the existing structural wall, new openings and two staircases connect the different levels and rooms, allowing the spaces to flow seamlessly both vertically and horizontally as a single, continuous interior.
The proposal also incorporates the existing basement beneath the street-facing room, creating a spatial sequence across three levels: basement, ground floor, and mezzanine. Within a limited footprint, the design maximises vertical openness and spatial continuity, creating an interior that feels significantly more expansive than its actual size.

Small Apartment Berlin