Wedge House: Ingenious Living on a Steep Slope

Innovative architecture maximizes space and views on challenging terrain

Wedge House stands as a testament to adaptive architecture, addressing the complexities of building on a steep, narrow plot at the foot of Mt. Satsuki. The residence’s unique wedge-shaped profile is a direct response to the site’s constraints—over half of the land sits on a steep incline, and the structure must avoid placing stress on an aging, tall retaining wall. This innovative form enables the building to expand upward, with the smallest footprint at the basement level and the largest at the uppermost floor, maximizing both space and panoramic views.

To comply with strict area regulations, including a 40% building coverage limit, the design employs a three-story mixed structure. The lower level, constructed in reinforced concrete, provides a secure, slope-hugging bedroom, while the two upper floors utilize wood for lighter construction. The second floor, boasting the best vistas, serves as the main living area, featuring a sky terrace that offers sweeping views of the Osaka plains. The first floor accommodates essential functions such as water areas and a study, with deep eaves framing the lush parkland behind.

Materiality plays a crucial role in both aesthetics and engineering. The east and west facades are clad in silver galvalume steel plates, which not only support the cantilevered upper floors but also frame the southern views, blending durability with visual lightness. This approach allows the upper wooden structure to project outward, maintaining the necessary living area without overburdening the retaining wall below.

Underlying the project is extensive research into stable, protruding structures in wooden buildings—a necessity given the site’s limitations. The design team, led by Kiyoshi Sugimoto, overcame significant challenges, including ensuring structural stability on a narrow, sloped site and integrating a pop-out floor system that preserves the integrity of the existing retaining wall. The result is a harmonious blend of regulation, innovation, and scenic integration.

Wedge House has garnered recognition for its creative ingenuity, winning Bronze in the 2025 A' Architecture, Building and Structure Design Award. The project exemplifies how thoughtful design can elevate quality of life, making the most of difficult sites while celebrating the surrounding landscape.

This residence not only meets the demands of its environment but also sets a benchmark for future hillside homes, proving that architectural challenges can inspire truly exceptional solutions.