Joey Valenti, a graduate in architecture from the University of Hawaii, has designed pre-built and affordable housing units made entirely of invasive albizia trees on the island of Oahu.
The Prefabricated Accessory Housing Unit (ADU) – a kind of little residence usually built in back gardens – is part of Valenti’s larger Albizia project that grew out of his seventh year dissertation.
The initiative aims to address Honolulu’s affordable housing shortages while restoring native forests. As with other island economies, Hawaii’s heavy reliance on imports contributes to sky-high property prices and the cost of living.
“Concern for homelessness in Hawaii is part of our core values, but we also need to resolve supply chain and ecosystem restoration challenges before pursuing commercial applications,” Valenti told Dezeen.
Valenti also wants to solve another problem of thirsty albizia trees, which can grow up to five meters per year and are problematic as their spread clogs water sources for the endemic flora.
They were originally introduced in Oahu in 1917 to reforest land previously used for ranching. In an ironic twist, the Hawaii Invasive Species Council is now encouraging the eradication of albizia trees to support the indigenous ecosystem.
“There’s an excess of this invasive species that people used to consider junk, just a problem,” he said. “I challenged that we consider it a resource instead.”
With funding from sources such as the Hawaii Housing Finance and Development Corporation and the US Forest Service, Valenti built a proof-of-concept called Lika on the campus of his alma mater, the University of Hawaii’s Manoa School of Architecture.
Lika’s design refers to the traditional architecture of the Pacific islanders using solid wood, such as the round Samoan fale with a thatched roof.
“At school we learned to base design concepts on elements of cultural significance, so I started exploring various low-tech native architectures in the Pacific Islands,” said Valenti.
“The beauty of indigenous architecture lies in its simplicity and structural integrity.”
Because Albizia is a soft, low-density wood, he used new technologies in wood engineering and digital CNC cutting to attach and cut boards, which were then glued into layered panels before being shaped into arches and beams.
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Valenti describes it as a “new version of cross-laminated timber”.
“It’s all laminated in the same direction, but these panels are almost like a thick layer of plywood,” he added. “This would stabilize the wood and give it extra strength before the parts are cut.”
Lika’s dome-like design is not only inexpensive, it also promotes air circulation through the use of wooden slats.
By eliminating three walls of a standard rectangular structure, natural airflow would reduce the need for air conditioning in Hawaii’s tropical climate. The ADU is covered with a waterproof canvas canopy that comes from a local manufacturer who makes commercial awnings out of fabric.
“Most of the time and labor is in the store,” said Valenti. “Once everything is pre-fabricated, the entire structure can be installed in about a day.”
ADUs are on the rise in some American housing shortages, including Seattle, where Best Practice Architecture converted an unused garage into a tiny black cottage for an older family member, and Toronto, where Measured Architecture added a back alley to a narrow residential property .
During this year’s Los Angeles Design Festival, a number of architect-designed granny flats were open to public tours. Also in California, the British startup has teamed up with prefabricated housing company Koto to develop a prefabricated, cabin-like unit that can be delivered to locations in San Jose in two weeks.
The photography is by Michelle Mishina.