From ‘trash’ tree to treasure

Three years ago, architecture doctoral candidate Joey Valenti envisioned turning a “trash” tree — prone to breakage, susceptible to rot and insects — into a treasure.

Albizia: arguably Hawaii’s most maligned invasive plant species, a real threat to life, property and Hawaii’s native forests.

Despite naysayers, Valenti persisted in designing an attractive, albizia-wood house sturdy enough to withstand hurricanes.

In the first few days of April, his vision blossomed on the grounds of the University of Hawaii’s School of Architecture, piquing the interest of passers-by. But the ease and speed with which the prototype is going up on University Avenue belie the months of planning and testing it took to get from tree to house.

It was exciting to see it finally take shape, Valenti said. The whole project was a statement “that we shouldn’t listen to what people assume.”

He took material that was thought to be unusable and created “something not just usable, but beautiful,” he said.

Valenti, 31, who earned his doctorate in 2016, strove to incorporate traditional Polynesian design, using an organic shape with a high ceiling and walls of louvers allowing for natural, cooling airflow. Use of available rather than imported materials fell in line with what Native Hawaiians did in the past, he said.

Valenti originally envisioned several structures as part of a village with a common kitchen. The individual houses would have a toilet, shower, kitchenette and loft bedroom. But the prototype will not include those amenities when completed by month’s end.

He drew from experiences studying and working in Copenhagen, Beijing, Shanghai and Singapore, but his work on large-scale complexes in China made him realize his path lay in smaller design with greater attention to detail.

“I wanted to dig for something that was in my passion, that highlighted Hawaii as the main focus of what I was solving for.”

He began looking at the environment and other areas to see what Hawaii was lacking. “I think that was the start of it.”

Albizia becomes the focus

In 2014, albizia trees uprooted by the powerful winds of Hurricane Iselle were hurled onto homes, power lines and roadways. Residents of storm-ravaged Hawaii island blamed much of the damage on unchecked forests of fast-growing albizia trees.

In 2015, while Valenti was formulating his doctoral dissertation, UH was scrambling to remove albizia from the Lyon Arboretum in Manoa ahead of the threat of impending hurricanes. Valenti’s dissertation chairwoman, Judith Stilgenbauer, suggested he look at the tree.

The arboretum gave him one of the logs that would have been dumped and Valenti used a chain-saw mill to rough-cut it into lumber, giving him his first taste of milling boards from a tree. He loved the hands-on work.

However, he had little experience working with the wood and “it was scary to hear experts saying, ‘You sure you can use this stuff? Because to the best of my knowledge it’s not useful,’” he said.

But in stress tests in the lab, albizia surpassed Douglas fir, which typically has knots and other imperfections. “Albizia is a cleaner piece of lumber,” he said. Despite it being a low-density wood with a softer feel, it’s surprisingly strong, according to Valenti. “The benefit is it’s lighter but still has the strength of some structural timber.”

He created a small-scale model for his dissertation, which won $10,000 in the 2016 UH president’s Green Awards Program to build a full-scale prototype.

But as with building any house, financing is always a concern. And while $10,000 seemed like a lot of money, constructing a prototype from raw materials was costlier than Valenti expected.

Matt Lynch, UH systems sustainability coordinator, who assisted in getting funding, figures the project got off the ground with roughly $78,000 in cash and about the same in in-kind donations from two mills, for a total cost of about $150,000. Valenti said he still needs to calculate the exact cost.

He said that after Hawaii Housing and Finance Development Corp. donated $30,000, “everyone jumped in,” including $17,000 from the UH systems, $20,000 from the UH School of Architecture’s discretionary funds, and the original grant funded by Johnson Controls.

Two mills assist

News of the endeavor caught the eye of sawmill owners Miles Luedtke and Elmer Maner at Waimanalo Wood.

“He was prototyping with chain-saw milling,” said Luedtke, who contacted Valenti. “Because of the scale of his project, he’s going to need someone with a band-saw mill.”

Band-saw mills use thinner blades than chain-saw mills and waste less wood.

They figured he would need 8,000 board-feet of lumber and offered to do the work at “a little better than breaking even.” They even agreed to store the lumber and did some kiln drying.

The bulk of the logs came from projects at Schofield Barracks and the H-2 freeway, with some from a Waimanalo nursery.

Albizia “was being vilified and being cast in a bad light,” yet it had a beautiful grain and the look of mahogany, Luedtke said. “Here’s someone who’s figured out how to make it strong. Our goal was to help him make it happen. It’s a proof-of-concept thing.

“I’m impressed with Joey,” he added. “He’s worked so hard to make it happen … He’s come from school into the real world.”

Valenti needed more sophisticated equipment to manufacture the pieces from the roughly sawed boards.

Enter Eric Bello of Bello’s Millwork, who provided shop time at cost.

There Valenti, with help from friends, turned the boards into panels, then laminated three panels together for strength.

He transferred his 3-D software plans into Bello’s computer numeric control machine, which made the precision cuts in the three-ply panels to create the components.

The prototype

Valenti gathered his team of volunteers — family from California, friends, architecture students and a few experienced builders. They began site work April 4, installing dozens of 26-inch aluminum screws into the ground to serve as a foundation.

On April 5, they began fitting the puzzle-like pieces together and hoisting up the curved arches of blond wood that form the ribs of the 19-foot-tall structure.

By April 6, the workers had raised all 13 arches and connected them to the spine and foundation, completing the framework for the 300-square-foot house, with an added 100-square-foot sleeping loft.

“I’m getting a kick out of how much preparation went into this, then in one day, poof,” said Steve Hill of the UH School of Architecture, who served as Valenti’s project adviser. “It looks so easy because so much preparation went into it.”

Valenti’s use of 3-D modeling software and digital fabrication combined with traditional Polynesian structural design is “a marriage of the old and the new,” Hill noted.

“It’s looking very good,” said Ian Robertson, a UH structural engineering professor, who helped test the tensile strength and flexibility of the albizia boards and all the connections.

“I didn’t think so, but it’s comparable to Douglas fir,” he said, as he watched it go up. He noted Valenti’s use of intricate hooks in the wooden joints.

“To make a big curve, you would have to waste a lot of lumber,” he said, so the joints were employed to connect shorter pieces. Stainless-steel connectors fabricated by UH engineering students slip inside the wooden pieces, adding strength. “It ends up being more complex and, therefore, more expensive.”

The shorter sections also allow for quicker assembly and disassembly.

The big picture

If enthusiasm for the prototype is any indication, Valenti may one day be responsible for creating a valuable solution to limiting the invasive tree species plaguing the islands.

By creating “a potential demand, then we’re incentivizing removal” of the albizia, Valenti said. “Eventually, we’ll want to run out of it … It’s a temporary solution.

“The big picture, as this phases out, is you’d see the native ecosystem come back.”

Valenti has applied for a federal grant with the U.S. Forest Service, teaming up with the state Division of Forestry and Wildlife, to thin overgrown forests of non-native species and create a demand for timber products from other species such as eucalyptus and toon.

He likened the use of locally sourced building materials to eating locally grown food, which may be a little more expensive than imported, but better all around.

“It’s a brilliant design,” Daniel Friedman, dean of the School of Architecture, said. “Joey embodies that which is the best of our school.”

Friedman said a visiting accreditation team “rhapsodized” over the innovative engineering and design project during a recent tour.

He said, “This takes a nuisance tree and transforms it into a highly innovative engineering and design into a marketable building product.”