Keiji Ashizawa transformed a cramped two-bedroom apartment set on a steep street incline in Tokyo into two open and airy units for a family and their grandparents. Dubbed the Sky Garden House, the project overcame strict limitations due to Tokyo building codes that discourage redesign by creating two volumes that are split by an open air spiral staircase and united by a common green roof garden.
The original home on the site was a small two bedroom with tiny windows and no connection to the outside. Ashizawa and the family sought to add a light and airy feeling to the new home, so the interior glass encased open courtyard was installed, stretching through three floors of the home. The courtyard serves as a lightwell, bringing plentiful sunlight to each floor. It also features a spiral staircase that adds another connection to the grandparents’ dwelling on the third floor. The lightwell also keeps each floor feeling open.
The roof, which initially held air conditioning units, was transformed into a lush roof garden, adding an extra storey to the home. The roof deck is used for family dining with the grandparents, as well as raising edible plants for the whole household to enjoy. In addition to that green feature, the incline into which the home is built varies in over 16 feet from each side. This leaves half of the first floor submerged and the insulation from the natural land helps to block solar gain and control interior temperatures saving the family utility costs. With its smart new design, the new home is a far cry from the cramped building that once occupied the same plot.
Via Arch Daily