From the architect. JUUL House, a two-generation residence designed by NKS Architects, sits adjacent to a river running through the suburbs of a small city in Fukuoka Prefecture. The client, a musician involved with music education in the local community, wanted a home that could also function as a small music hall. Because the client works in the cement business – a major regional industry – the architects used concrete as the primary construction material.
Give us an overview of the project.
The lot is a long, slightly irregular rectangle aligned north-to-south, with a river running along the south-east side. The river’s mouth is not far away and so it is quite wide at the point where the house stands. Although the lot is surrounded by houses on three sides, the view towards the river and rice fields on the far side is completely open. The setting is rich in natural beauty, with the Chikuhou Mountains visible to the west.
The character of the interior spaces differs on each floor. The first floor, which opens onto a garden that runs from north to south, includes a large entryway that also serves as a gallery and a living room that doubles as the music hall, as well as a dining room, kitchen, and bedroom used primarily by the younger generation. The distinctive curved ceiling is interspersed with skylights that bring soft light into the space. In contrast, the second floor, where the older generation lives, opens to the east and west overlooking the river and the rich natural scenery. Compared to the first floor the scale of the spaces upstairs is much smaller and more enclosed, but because of the expansive views they do not feel oppressively closed-off. The cubicle-like rooms were designed as places to relax sitting on the floor.
The two very different areas of the house are divided by curved concrete that forms the ceiling downstairs and the floor and walls upstairs. Painted white, these curved walls softly scatter the light from the skylights, and do the same for sound when concerts are held in the home.
What was most important for you during the design process?
One central point was that the space functions not only as a home but also as a small cultural facility (both a music hall and gallery). Another point that I always think about is the need for the spatial design to logically mesh with the structural framework of the building. This time, I also explored the potential of concrete spaces.
What challenges did you face in the project? How did you respond to them?
As part of our goal of creating a structure that expresses the possibilities of concrete, we focused in particular on technical innovations to ensure a high-quality thermal and acoustic environment.
In terms of the thermal environment, we stabilized the interior temperature by completely enclosing the concrete – which functions as a heat storage body – with exterior wall insulation. On the east and west sides we added another layer of concrete on top of the insulation in order to unify the design. To keep the interior from overheating in summer, we installed awnings over the large windows and doors, used low-emissivity glass in the skylights, and created pathways for heat to escape.
In order to ensure acoustic performance, primarily for classical music, we focused on making sure the convex surfaces of the concrete ceiling diffuse sound properly. To control reverberation time, we opened numerous holes in the surface of the concrete and inserted acoustic absorbent material. The type of acoustic environment needed varies depending on the size of the audience and the types of instruments, among other factors, and here it can be adjusted to a certain degree by opening or closing the sound-absorbing doors and curtains in the room.
What did you learn from this project? What will you take from it to future projects?
I was able to confirm the effectiveness of skylights for bringing in natural light, as well as of external wall insulation in concrete buildings. On the other hand, I realized that I need to think further about the balance between the quality and cost of architecture.
How does this project fit into current architectural trends such as sustainability, social function, or technology?
When I think about creating sustainable architecture, I focus on using materials in a way that allows their character to emerge as they age. Contemporary architecture tends towards the minimalistic, inorganic forms representative of standardized factory products. In this project, although I used concrete, which is an inorganic material, and modern construction techniques to create a new kind of space, I tried to incorporate a human warmth into it.
I also thought about how a residence, while belonging to one individual, can also be open to the local community and serve as a cultural resource that is used long into the future. Perhaps it is only within the framework of such a local community that the long-term value of culture can be preserved in an era dominated by the short-sighted principles of the global economy.
What is the societal role of the architect?
Architecture has the potential to become a cultural and social asset, and I think architects have a responsibility to stay conscious of that when they design buildings. Even residences can go beyond their role as the space for individual lives and serve as community assets. If you think about it, just a few generations ago homes in Japan were used as sites for the ceremonial gatherings that helped create communities. In this project the space not only enriches the life of the client, but through its function as a concert hall and gallery it becomes a center-point for enriching the entire community.