Made from natural mineral compounds, this alternative to standard concrete masonry units mimics the look of raw rock.
Digital Sustainability's insight:
Portland cement is a material that architects and designers who deal in sustainable construction love to hate. But until recently, the market has seen few sustainable alternatives, particularly for structural applications. That’s changing. Among the products aiming to fill the gap is a new masonry unit from Napa, Calif.–based Watershed Materials, which is led by rammed-earth construction evangelist David Easton. The modular Watershed Block is made of fused soil and rock fragments including quartz, feldspar, clay, and other minerals. The hollow-celled unit contains half the cement of typical concrete blocks but weighs up to 30 percent more. EcoBuilding Pulse talked with Easton about the new block and how it could make masonry construction more environmentally friendly. What is your goal for the Watershed Block?We’re trying to eliminate our dependence on energy-intensive Portland cement and develop a series of formulas that allow us to recreate the original Roman cement, in which a suite of volcanic ashes were blended with lime and rock fragments to create this amazingly durable concrete. Portland cement is a fantastic product because it can glue sand and gravel together to make enormously strong finished products—7,000 to 10,000 psi. Roman cement can’t attain those strengths but there are very few applications for which you need something to be that strong. For architects and designers working with a client, what’s the selling point?You take one of the most common building components in the world and you make it better—more resource-conserving, energy-efficient, geographically appropriate, completely recyclable, and with a smaller carbon footprint. And it’s structure and finish, which is really efficient. Your masons lay it up and it’s done. There’s no Tyvek, there’s no painting, there’s no lathing on the outside. It’s very compelling if you have a short project timeline. We’ve worked hard to develop a series of formulations that make the block look like raw rock....