Are you perhaps dreaming of a house made of hemp? I never had until earlier today-constraining my visions of domestic bliss to homes made of straw bales or even timber with straw/clay infill-then I happened upon this: "The house you don't need to render, plaster, paint or insulate.
The house with the building material that you can grow on one hectare (2.5 acres) of land. The same building material you can process yourself with standard machinery available at your hardware store. The house whose walls lock away over 110 kg (240 lb) of carbon per cubic metre." And, I might add, the house that all the huffing and puffing of the big bad wolf will fail to budge, such is the strength of Hemcrete, a substance that's the vegetable equivalent of the fruits of the labor of Klara Marosszeky of Australia's Northern Rivers Hemp, Inc.
Cottage in Australia made from Hemcrete.
The new building material represents a revolution in hemp building, since it incorporates the entire hemp stalk via rendering and mixing with lime plaster. The method avoids the costly and energy intensive process known as decortication, meaning, effectively, that you can grow your own house on your very own land.
Since hemp cultivation is-ahem-frowned upon in the U.S., the prospects for widespread use of the material state-side might seem dim. Yet Asheville, North Carolina's Push Design somehow managed to source the stuff and build a 3400 sq. ft. house for two prominent Asheville residents (former mayor Russ Martin and his wife Karen Korp).
Hemcrete is somewhat similar to non-load-bearing straw bale construction. The house is conventional stud framing with Hemcrete infill. Once studs are up, builders erect forms and fill them with the newly-mixed substance, which then hardens to provide a breathable, sound-proof, and energy-efficient insulation. The substance effectively functions as the building's skin as well, requiring for finishing only an interior and exterior application of stucco.
Use of Hemcrete thus saves time and money because it's faster than traditional construction and requires fewer materials: say goodbye to plywood sheathing, odious fiberglass insulation, troublesome vapor barriers, and-most especially-crumbly drywall. Nor do you need to paint a Hemcrete wall since lime stucco can be tinted before application.
Anthony Brenner and David Mosrie of Asheville's Push Builders are especially optimistic about the domestic use of Hemcrete. According to Brenner, the material "offers incredible benefits to the homeowner and environment alike... a 'carbon negative' breathable wall system that is both energy efficient and produces indoor air quality beyond any other building system available today."