Credit: Tom Adams
In his 35 years as a structural engineer, Bruce King has built many, many structures—from high-rises in San Francisco to aircraft in Miami to resorts in Tahiti. But it wasn’t until he was asked to design the Real Goods Solar Living Center in California in the early 1990s that he realized that you could use something other than Portland cement to construct a structurally sound building.
Using materials like straw bale and recovered fly ash to build the Solar Living Center instantly resonated with King, who has always hated the wastefulness of the construction industry. “I’ve always been kind of obsessive about not throwing anything away and wanting to reuse everything,” he says.
Now, 20 years later, you can find King traveling around North America giving daylong seminars on how to build homes with natural materials like clay or what he likes to call “urban natural materials,” which could include barbed wire, tires, or other common materials in the urban environment that can be reused. He is the founder of the nonprofit Ecological Building Network and is the author of books on straw-bale construction and high-volume fly-ash concrete. He also wrote the ASTM building standard for earthen buildings.
More recently, King took his engineering knowledge to Port au Prince after the region’s devastating earthquake. His goal? To teach Haitians how to build with local resources like concrete rubble and bamboo instead of the imported steel and wood that other countries were sending them. “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 a blog post. “We have a better idea: rebuilding with the people and materials at hand—the ‘natural’ solution.”
It is with that mind-set that King envisions a world in which local industries look to each other to share resources; a world in which builders source straw from local farmers and metal from automobile manufacturers to construct low-carbon, healthy 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 says. “We should start to treat all the waste flows from every industry as resources for the construction industry.”
King believes this concept is well within the realm of possibility, but he also realizes it will take a lot more time and effort than anyone is 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.”
For King, a more feasible goal for the industry—at least within the next 10 years—is to apply Amory Lovins’ strategy and reduce the carbon footprint of building materials by a factor of 10. He clarifies that the industry can’t reduce the amount of material used by a factor of 10—there are laws of physics that prevent that from happening—but it can easily reduce the impact those materials have on the environment.
The first step, he says, will be finding an alternative for Portland cement—the glue that holds cement together. “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.”
Although finding a replacement for Portland cement has been a technological barrier for the industry, King says that he and several other engineers have found ways to reduce the amount of Portland cement by using by-products that are readily available, 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 says. “The concrete foundation accounts for the most carbon or embodied energy of any single material in the whole house. That’s a huge target.”
He also thinks we need to replace wood fiber with straw fiber. In fact, King says straw can be used in just about any application, from insulation to enclosures. Ideally, he would like to see builders utilize the straw fiber coming out 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 (normally timber) to provide a wall build system. “It’s a great insulator, very durable, and never rots,” King says.
The most necessary change, however, will have to happen at the educational level—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 says. “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.”
King would also like to see more builders do their part by educating themselves and, even more important, by investing in healthier, low-carbon materials. “There are good products 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.”