Japanese Prefab Housing

The case for considering aluminum material for prefab homes

BY DR. AVI FRIEDMAN

DID YOU EVER WONDER why prefab houses are sought after by Japanese homebuyers but not looked upon more favourably in Canada? The answer may lie in innovation, use of new materials and in placing buyers’ comfort front and centre.

The Japanese prefabricated housing industry is a world leader in building innovation, featuring efficient production processes, targeted marketing strategies and high-quality designs. Contrary to popular North American beliefs, Japanese society perceives factory-manufactured housing to have quality superior to that of conventionally built housing. Fully computerized to maximize efficiency, the process takes advantage of advanced digitization to allow for a cataloguing system that end users can use to customize their homes using standardized components.

Manufacturers have developed an innovative user-oriented approach that allows clients to interact with and learn more about the product before purchasing. Homeowners, for example, are willing to spend slightly more money to reap the benefits of lower extended maintenance costs.

Japanese prefab houses accommodate the need of families in the flexibility they offer while recognizing that lifestyles may grow and change. They are also environmentally sustainable due to the minimal waste produced in an optimized factory production setting. Consider the A-Ring House in Ishikawa.

Architectural firm Atelier Tekuto worked with several universities and companies to develop materials and technologies to help create an environmentally friendly home. The 1,471 sq. ft. project focused on developing a single aluminum component that can serve various functions at once.

The main structure is composed of an aluminum ring and aluminum column and beam frame. There are four aluminum moulds, developed by the architects and their partners, that interlock to form the ring shape. In addition, modified deck plate moulds are composed of columns, walls and binding joists held together using ordinary bolts. As a result of these interventions, the design firm was able to achieve higher construction quality, reuse materials and reduce waste.

Furthermore, composite units that combine structure, a radiant heating/cooling system and water section were developed. The ring fully integrates the heating/cooling system into the structure by passing a pipe through the prefabricated aluminum components to create a large radiator and further structural elements. The home’s “wet functions” (bath and kitchen units) were also built into the aluminum rings.

To minimize the running costs and environmental footprint, the home relies on renewable energy systems. An energy-harnessing unit was developed to obtain heat from groundwater and geothermal energy using solar power. Embedded into the ring, the system reduces energy costs by half. Furthermore, LED lights are incorporated into the structure, using aluminum’s reflective properties to illuminate a greater area. All other light fixtures were replaced with LEDs.

In addition, “green curtains” were developed as part of a second-floor roof garden to reuse captured rainwater. By passing a hemp cord through an aluminum frame, the plants wrap around the cord to create the natural curtain. The rainwater collection tanks were installed to allow water to circulate inside the frame while a portion of the water is used to mist the plants and cool the inside of the house.

While aluminum is still uncommon in the building industry, data gathered from this project might help it become an essential building material alongside concrete, steel and wood.

DR. AVI FRIEDMAN IS AN ARCHITECT, PROFESSOR AND SOCIAL OBSERVER. HE CAN BE REACHED AT AVI.FRIEDMAN@MCGILL.CA.