Optical Glass House / Hiroshi Nakamura & NAP

Textual content description offered by the architects. This home is sited amongst tall buildings in downtown Hiroshima, overlooking a avenue with many passing automobiles and trams. To acquire privateness and tranquility in these environment, we positioned a backyard and optical glass façade on the road facet of the home. The backyard is seen from all rooms, and the serene soundless surroundings of the passing automobiles and trams imparts richness to life in the home. Daylight from the east, refracting by way of the glass, creates stunning mild patterns. Rain putting the water-basin skylight manifests water patterns on the doorway ground. Filtered mild by way of the backyard timber glints on the lounge ground, and an excellent light-weight curtain of sputter-coated steel dances within the wind. Though situated downtown in a metropolis, the home permits residents to benefit from the altering mild and metropolis moods, because the day passes, and reside in consciousness of the altering seasons.

Optical Glass Façade
A façade of some 6,000 pure-glass blocks (50mm x 235mm x 50mm) was employed. The pure-glass blocks, with their giant mass-per-unit space, successfully shut out sound and allow the creation of an open, clearly articulated backyard that admits the town surroundings. To comprehend such a façade, glass casting was employed to provide glass of extraordinarily excessive transparency from borosilicate, the uncooked materials for optical glass. The casting course of was exceedingly tough, for it required each gradual cooling to take away residual stress from throughout the glass, and excessive dimensional accuracy. Even then, nonetheless, the glass retained micro-level floor asperities, however we actively welcomed this impact, for it could produce sudden optical illusions within the inside house.

Waterfall
So giant was the 8.6m x 8.6m façade, it couldn’t stand independently if constructed by laying rows of glass blocks a mere 50mm deep. We subsequently punctured the glass blocks with holes and strung them on 75 chrome steel bolts suspended from the beam above the façade. Such a construction can be weak to lateral stress, nonetheless, so together with the glass blocks, we additionally strung on chrome steel flat bars (40mm x 4mm) at 10 centimeter intervals. The flat bar is seated throughout the 50mm-thick glass block to render it invisible, and thus a uniform 6mm sealing joint between the glass blocks was achieved. The consequence　—a clear façade when seen from both the backyard or the road. The façade seems like a waterfall flowing downward, scattering mild and filling the air with freshness.

Captions
The glass block façade weighs round 13 tons. The supporting beam, if constructed of concrete, would subsequently be of large dimension. Using metal body bolstered concrete, we pre-tensioned the metal beam and gave it an upward camber. Then, after giving it the load of the façade, we forged concrete across the beam and, on this manner, minimized its dimension.