Jun Igarashi Hat H

"Hat H", designed by Jun Igarashi, is a project produced from significant economic and climatic constraints for a family in Engaru, Hokkaido. The timber residence, measuring 5.460m x 5.460m at grade, is located on a spacious lot of 373.09 sqm, adjacent to the banks of a riverbed at the periphery of an urban area. Hokkaido's climate—known for its extreme seasonal variance—became the conceptual focus of the residence, which functions as both a viewing apparatus to appreciate seasonal change and a modifiable structure through which to thermally engage it.

Due to local frost depth codes, requiring foundations to be at least 900mm below grade, the project began with the intention of utilizing a minimal footprint to generate a rich environment in section. The basement level, capitalizing on the earth’s thermal mass, contains the project’s bedrooms, washroom, and study, and is joined to the remainder of the project via a steel spiral stair.

The first level supports an open floor plan containing a dining room, kitchen, and a lounge. Its birch floor plane cantilevers 1.8m in all directions, as a veranda, allowing the airy level to visually extend into the surrounding Hokkaido landscape.

A series of glazed double-doors are set into this level’s facades, lending them operability and the capacity for passive conditioning. The roof of the residence mirrors the veranda below, though extends further to function as a canopy (in addition to formally resembling a “hat”).

Coniferous plywood, with a 12mm substrate, is used for the project’s structural members, which are left exposed to suggest a clear construction logic while the project is navigated in section. This clarity of architectonics, in conjunction with the project’s ability to thermally adjust to its situation, enables the house’s inhabitants to live in their environment consciously and actively.

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