Awaji, Hyogo Prefecture, Japan

Ryuichi Ashizawa and his team are responsible for the Spiral Garden, a residential project dedicated to a four-member family that resides on the slope of Awaji Island, Japan. The design considers the temperate nature of the Island, as well as the family’s distinctive, nature-conscious approach to all aspects of life.

The Spiral Garden project was short-listed for a 2021 International Architecture Award from The Chicago Athenaeum and The European Centre for Architecture Art Design and Urban Studies.

In response to its context, the house employs local timber construction. It has a unique form, consisting of a continuous spiral that rises towards the central space. This space has an openable skylight. In summer, an open skylight lets air Circulate as a Chimney effect. In winter, the soil floor will collect heat from the sun, heat will rise up toward the spiral structure and warm up the whole house.

The project is on a 1,000 m sqm site on Awaji Island, Hyogo, Japan. To make use of the site to its’ maximum extent, the house and its’ landscape were planned at the same time. The client, a family of four, requested, “Instead of a finished house, we want a house which we can complete on our own; a house that grows along with the family.” The request prompts the office to re-think the ideal residence for the family. Three years of the design process has stripped away the excess while keeping the essentials intact.

The office explored a more primitive architectural approach based on a family gathering. It resulted in a spiral, continuous plan that is in contact with the exterior at all sides, with rooms such as storage and bedroom on its’ fringes. Extension for children’s bedrooms in the future is also accommodated. Various possibilities between the house and the garden emerged upon inspection of the plan.

At the core of the house is an unassigned space, Niha, with a diameter of about 2.4 m and a height of 7.5 m. From the kitchen and dining room where the family would gather, the Niha is hidden from sight. During the day sunlight seeps through the skylight atop the Niha, with a diameter of 600 mm.

At night darkness sinks as there are no lights installed. When opened, the skylight also functions as a tunnel to which the wind ascends from the ground. As it is unassigned to a pre-defined function, the center of the house is free to be used for miscellaneous activities, be it meditation or gathering with friends. Its’ existence is significant in which it caters to the family’s life dynamics.

The roof is planned as a spiral garden, in which the ground rises towards the sky.

The roof forms a spiral whose edge touches the ground, connecting the second floor to the garden below, seemingly integrating the house and its’ environment. This form collects the rainwater and will flow through the garden to out of the premises immediately, a system in which water penetrated throughout the site.

To support the roof, timber beams follow the spiral and ‘radiate’ from the central space, exposed in the interior. Every part of the timber construction was hand-carved by carpenters.

The inner and outer walls finishing is as same as traditional Japanese houses, made of soil from Awaji Island. It is a hard-packed earthen floor consisting of earth, lime, and water that is beaten until solidification and is extremely resistant to high foot traffic. Its’ interior wall was finished with Awaji Island’s Earth on top of an interwoven lattice of Bamboo collected around the site. The outer wall is scraped with a finishing of soil and mortar, while the floor used a technique called “Tataki”. The interior earth finishing is able to store heat and control humidity.

The roof is a spiral garden where growers raise their spirals while the ecology continues from the ground. Since the shape is spiral, various directions and heights can be obtained, so that various plants can be planted according to the sunshine and humidity.

In addition, water falling on the roof gradually descends without sweeping down by the planned swirl and is led to the reservoir while moistening everything. The water in the irrigation pond delivers cold air into the house in the summer. Using trees and soil, the architects decided to create a place of living where they always felt the assets of light, wind, water, and green. In the summer, the incoming wind will be cooled by the pond before it enters the house.

Throughout the garden, trees to be planted have been planned accordingly. It is hoped that by introducing natural phenomena as inseparable parts of the house, the family would be one with nature; in the form of a house where the earth and trees grow, in which the house and the garden complement each other. When the house is complete, the story of the growing house and garden has only just begun.

Project: Spiral Garden
Architects: Ryuichi Ashizawa Architects & Associates
Client: Ryuichi Ashizawa Architects & Associates
Contractor: Ryuichi Ashizawa Architects & Associates
Photographers: Kaori Ichikawa