“Coffee-cup home” showcases wood-free construction
Nancy Hall was looking for a forest-neutral way to construct a house on her 20 already-logged-over acres in Quilcene, Wash. She considered other darlings of the alternative-materials scene, but in the end chose Rastra — blocks of insulated concrete foam. And how do you Rastra, mon? Take recycled polystyrene coffee cups. Mix ’em with cement, curing agents, and air. Stack ’em up like Legos. Cover with plaster (interior) and stucco (exterior). The result: A wonder material that resists earthquakes, fends off fire, insulates against sound, and lends itself to creative manipulation. Hall kept recycling by collecting and embedding empty liquor bottles in her Rastra walls as light catchers — “The [turquoise] Bombay gin is by far the best color,” she says — just the proof we’ve been waiting for that drinking martinis is good for the environment. Others have built castle-like towers and dramatic porticos with the adaptable foam blocks. We’re going to start drinking coffee and booze right now, to prepare for constructing our own Rastra castles.