Kazahana.

At almost every level, the building has had to address significant challenges, and the process tested the capabilities of all involved. The result is an achievement in terms of building, engineering, services and teamwork. It is a very technical building in a forest towards the top of a mountain that can only be accessed by road for 6 months/year.

The house addresses an extreme range of climatic conditions. In summer, it faces very high humidity and moderate temperatures. In winter it faces cold dry air and some of the highest snow loads on earth. The entirely timber structure is designed to carry up to 4m of snow on the roof (approximately 1.2 tonnes/m2). This is particularly relevant in an earthquake prone location. Snow can build up around the house to 5m requiring careful negotiation of entry points according to the season.

It is designed to Passiv Haus level of airtightness (0.6 ACH), with 400-500mm of insulation in the walls and roof. Systems required to manage fresh air, temperature and humidity in such conditions are complex and customised to the particular requirements of the owners.

The roof is detailed to minimise icicle build up and to manage snow retention or removal as the situation dictates.

The client committed to the preservation of almost all of the 200 year old Japanese Beech trees on site which governed the siting and form of the house, as well as the excavation and footing method.

Externally the house is clad in copper for longevity and for the subtle patina which echoes the trunk colouration of the Beech trees. Internally it is lined almost entirely in Hinoki and Japanese plaster. Stonework, joinery and basins are all produced locally.

Working between Australia and Japan with architects and consultants based in both countries presented obvious pragmatic challenges, however these were undoubtedly outweighed by the richness that resulted. It is definitely the most complex project any of the architectural offices have been involved with, and there is a corresponding level of satisfaction to come from its completion.