The company’s chemists tested 5,000 recipes before they came up with EcoRock’s stew of 20 materials. The fly ash, slag, kiln dust and fillers—85 percent of which are industrial by-products—react chemically when mixed with water and bind together into a paste that’s poured into sheets. The oven-free process uses just 20 percent of the energy of the typical method. And without the starch and cellulose that’s mixed into ordinary gypsum boards, EcoRock is impervious to termites and mold. It costs about the same as high-end drywall, so it may find a home in houses both green and mainstream. $14–$20 per 4×8-ft. sheet; seriousmaterials.com
