Slur House in Suburban Tokyo Connects Old and New Homes with Shifted Roofs

In a suburban residential neighborhood of Tokyo, Japan, Yohei Ikai of icai architects has completed Slur House, a detached annex added to a 15-year-old single-family home. Built on a 140-square-meter lot, the project expands the existing property to accommodate a growing family that requires greater individual independence while preserving visual and spatial connection to the original near-square, pointed-roof house with its simple white exterior walls.

The architectural layout references the musical concept of a slur, where separate musical notes are played in a smooth and continuous manner. The design establishes a deliberate gap between the two buildings, serving as both a spatial boundary and a connecting device that organizes the fragmented landscape typical of suburban Tokyo developments.

Stock photo for illustration only, not from the actual event

A key spatial feature of the annex is its ridge beam, which shifts toward the existing house to create a higher ceiling height and draw focus toward the older residence. A high-level side window captures sunlight bouncing off the large white wall of the original home, which previously functioned as a rear elevation facing a neighboring property. This architectural interaction transforms the former back wall into a dynamic light-reflecting surface that illuminates the interior during morning hours.

Inside the compact 30-square-meter interior, two lofts, freestanding columns, and a looping circulation path organize the vertical space. South-facing windows are arranged in an upward sequence leading toward the high window overlooking the main house. Collaborating with textile designer some/to, the design team created gradient curtains in a pink tone that connect windows of varying dimensions and heights, filtering daylight differently throughout the day.