Treehouse Rising
Architect Aaron Ackerman’s fantasy of constructing a family home in Pālolo Valley challenges the idea of what it means to be green, and the result is on track to be the first residence certified as a Living Building in Hawai‘i.
Tucked deep in the recesses of Pālolo Valley, where clouds hang over green creases of jungle infringing upon its twisted streets, sits a house hidden high in the foliage. To reach it, you must enter the property at the bottom of a steep hill and climb a long flight of natural-stone pavers through ferns and heliconia. Gazing up from the end of the path at reclaimed redwood dripping with flora—Spanish moss hanging in front of windows, acting as natural sunscreens—it is hard to tell where house ends and forest begins. That is exactly the point.
When architect Aaron Ackerman bought this plot in 2011, his wife, Jessica, was pregnant with their first child, and they ambitiously set out to build a green home, a living space in sync with its environment. They fixed up and moved into a humble, treehouse-like structure that was already on the property and spent the next few years studying the land: the vegetation, topography, and where the water went when it rained. It wasn’t until four years later that they started construction on the final version, using this data to inform how and where they built.
The site, like any treehouse, evokes a child’s dream. The couple’s three children, who are aptly named for the three elements found in every woody plant—Xylem, Cambium, and Phloem—hang out in nets high in the trees. It has a zipline winch system that looks like a prop out of Hook, featuring a repurposed WWII Marine cauldron from Maui found buried on the property as a carrying container, which Aaron installed to haul a 500-pound, stone birthing tub up to the house. Of the house’s building materials, 75 percent are salvaged or reused.
Aaron has worked as an architect and sustainability facilitator at Bowers and Kubota for 15 years. This might be the firm’s most ambitious project yet. Its name is Haleola‘ili‘āinapono, an amalgamation of the Hawaiian ideas of a living house (hale ola) managed by an individual for the betterment of the community (‘ili ‘āina) in a morally conscious way (pono).
The purpose of this house is to raise the bar for what people consider an environmentally friendly building. “How we live has an impact, and we spend, on average, 90 percent of our time indoors,” he says. “That means that we are very impacted by the buildings that we occupy.” There have been LEED-certified developments in Hawai‘i before, but Aaron built his house based on a much more stringent set of rules outlined in the Living Building Challenge.
Created by the International Living Future Institute, the Living Building Challenge is a list of 20 imperatives a building must fulfill to receive its Living Building certification. Its criteria are challenging, including a building that generates all its energy from renewable resources and uses rain catchment for all its water, with all wastewater and stormwater reused for urban agriculture or groundwater recharge. In short, a building that passes this test aims to do more than just save some energy—it aims to have a net-positive impact, giving back more to the land than it takes.
Aaron had to get creative, as building in Hawai‘i poses unique challenges. One of the rules of the Living Building Challenge is that the majority of the materials used must be sourced locally. He figured that the few native materials available, such as lava rock and koa and ‘ōhia woods, are better left preserved, so he turned to the steady stream of waste generated by the demolition of single-walled homes on O‘ahu. This provided materials, like cedar and redwood, that had already proven resistant to Hawai‘i’s high humidity, corrosive air, termites, and extreme ultraviolet rays, which the project saved from the landfill.
While the home is well-equipped with state-of-the-art appliances and devices, Aaron’s true inspiration was nature and Hawaiian culture’s relationship with it. Water, for example, is an important, protected resource to Hawaiians. The roof is vegetated with laua‘e ferns to absorb stormwater and keep the house cool. Wastewater from the toilets and kitchen sink is treated aerobically and filtered through a wetland before it irrigates the a‘e tree (Hawaiian soap berry), whose berries can be used as a laundry detergent. Greywater is stored under the house for future use after any heat it retains is extracted to heat new water. Collected rainwater is used for everything from drinking water and showers to irrigation for more than 25 varieties of fruit trees on the property, including lychee, macadamia nut, coffee, and mango.
Some of the imperatives of the Living Building Challenge go beyond quantitative measures to demand qualitative aspects that are much harder to measure. To Aaron, these are the most important. Biophilia, for example, is the innate human tendency to seek connections with nature, and to meet this Living Building imperative, he designed his home to echo the surrounding nature with natural ventilation and biomorphic forms. “The house is an experience,” he says. “It offers perspective, sanctuary, mystery, and risk. As you are experiencing the house, it draws you around the next corner, you never really see the whole thing.” Local artist and friend Maya Lea Portner used reclaimed tile to create earthy mosaics that dance over the stairs and through the bathroom. A bright orange, midcentury modern Condon King Aztek fireplace from Reuse Hawaii brings humans’ natural attraction to fire to the living room.
The house is on track to be finished at the end of 2019, after years of work by the Bowers and Kubota team, help from donors and partnering companies, and the support and patience of Aaron’s family. Then it will begin a year-long Living Building assessment. If it passes, it will be the first certified residence of its kind in Hawai‘i. (Big Island’s Hawai‘i Preparatory Academy is a Living Building.) Homes such as this one could not only solve dire emergencies Hawai‘i faces of polluting cesspools, freshwater shortages, and landfills at capacity from construction waste, but could also get us back to living in harmony with the land. “We can’t just look at the bottom line from an economic standpoint,” Aaron says. “We have to ask how the decisions we make impact society, the environment, and economics.”
But for Aaron, the human desire for connection with the natural world is the driving force behind Living Buildings, and what will ultimately inspire others to live more sustainably. “Solar panels don’t inspire humans,” he says. “Humans are inspired by nature, and they respond positively—mentally, spiritually, physically—to an enhanced relationship with nature. This is the utopic feeling people get when they experience a building like this.”
[Originally featured in Flux Magazine, July 2019]