In his thirty-five-year career in structural engineering, Bruce King built several structures—from skyscrapers in San Francisco to an aircraft in Miami to many resorts across Tahiti. But it wasn’t until in the early 90s when he was roped in to design the Real Goods Solar Living Center in California that he decided to explore ways to construct structurally sound buildings using materials other than Portland cement. Building with straw bale and recovered fly ash to conceive the Solar Living Center instantly resonated with King, who has always been articulate about the waste utilization techniques of the construction industry. “I’ve always been kind of obsessive about not throwing anything away and wanting to reuse everything,” he stated.

Urban Natural Materials

Today, many years later, you can find King traveling around North America conducting seminars on how to build with natural or local materials like clay or what King termed “urban natural materials,” which could include barbed wire, car tires, or any other “waste” materials in the urban environment that can be reused as a construction material. Being the founder of the nonprofit Ecological Building Network and the author of books on straw-bale construction and high-volume fly-ash concrete, King’s contribution to building with local materials has been immense. He also wrote the ASTM building standard for earthen buildings. More recently, King took his engineering skills to Port au Prince after the region’s devastating earthquake. King aims to teach Haitians how to construct with local materials like concrete rubble and bamboo instead of the imported steel and wood. “A hungry man does not so much need a fish but a fishing pole, and though that ancient folk wisdom gets endlessly repeated, the world keeps sending fish,” King wrote in one of his blog posts. “We have a better idea: rebuilding with the people and materials at hand—the ‘natural’ solution.”

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Straw Bale Construction By JonathanCross_©

A World in Which Industries Share

It is with that mindset that King envisions a world in which industries look to each other to exchange and share resources; a world in which architects source their materials from local farmers and automobile manufacturers to construct low-carbon, sustainable homes. “Instead of scraping the stuff out of the ground in big open-pit copper mines where nobody wants or cutting down old-growth forests, what if we started harvesting more aggressively out of the urban environment,” King said. “We should start to treat all the waste flows from every industry as resources for the construction industry.” King believes that while this idea is well within the realm of possibility, it will take a lot more time and effort than we are currently willing to invest. “Right now, the financial interest isn’t there,” he says. “If you get the carrot out in front of the donkey, he’ll move. But the carrot isn’t there right now, so the donkey isn’t going anywhere.”

The Footprint

According to King, a more attainable goal for the industry—at least within the near future—is to apply Amory Lovins’ strategy and shrink the carbon footprint of construction materials by a factor of 10. He clarifies that the laws of physics don’t allow the industry to reduce the amount of material used by a factor of 10—although it can easily reduce the impact those materials have on the environment. The first step, he says, will be developing an alternative for Portland cement. “The production of Portland cement accounts for 5% to 7% of the anthropogenic greenhouse gases that are produced every day or every year,” King says. “We have to find a better way to hold our concrete together,” King added that he and several other researchers have developed ways to reduce the amount of Portland cement by replacing it with readily available by-products, most notably coal fly ash and other pozzolans. “We can make better concrete of equal or better quality to what we do now with a lot less Portland cement and a lot less toxic and energy effects,” King stated. “The concrete foundation accounts for the most carbon or embodied energy of any single material in the whole house. That’s a huge target.”

Straw and Hemcrete

King also thinks we need to replace wood fiber with local materials like straw fiber. He notes that straw can be used in just about any application, from insulation to enclosures. Ideally, he would like to see architects utilize the straw fiber coming out of the fields as a by-product of food production; however, he also recommends a new alternative insulation material coming out of the United Kingdom called Hemcrete. The insulating material is a mixture of hemp and lime plaster and is designed to work in conjunction with a structural frame (commonly timber) to provide a wall build system. “It’s a great insulator, very durable, and never rots,” King stated.

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Hemcrete ©

A Change in Education

The most necessary change, however, will have to happen in school and college—a challenge King is trying to personally address. “If you are not going two or three or four stories high, there are an awful lot of things you can build with that the building code doesn’t even notice and essentially accepts, like adobe or straw bales or bamboo or stonework,” King stated. “Most engineers in the world have no training whatsoever in those things, and they don’t know how to deal with it. Part of my effort is to get things into educational institutions—getting to students in engineering schools and at least prying their minds open a little bit.” He would also like to see more architects do their part by educating themselves and, even more important, by investing in healthier, low-carbon, local materials. “Good products are coming out, and they need the support of people buying them,” King says. “Be an effective agent for change by spending your money in the greenest possible way and then support the industries that are trying to do the right thing.”


Sowmya is an architectural journalist and writer. In this column, Sowmya takes you through stories on eco-architecture, biophilic design, and green buildings from across the globe.