Architects Show Off ‘Hempcrete’ Studio
British Architects Pioneer Hempcrete Studio as Sustainable Building Model.
A pair of British architects are using their own studio as a proof-of-concept in their commitment to sustainable building practices.
Kate Nicklin and Graham Mateer, the directors of Commonbond Architects, an architectural firm in London, work in a self-built studio located in the garden behind their bungalow.
Nicklin and Mateer had an additional motivation for the studio. As the website AJ Building Library explains, the couple wanted “to explore the potential of using hempcrete as a breathable biocircular building material.”
“The main idea behind the project was to create something that felt permanent and not like a standard lightweight timber shed,” Nicklin told Dezeen, which noted that, in addition to hempcrete, Commonbound Architects also “used reclaimed materials and a timber frame to create the cuboidal volume, which is topped with a mono-pitched roof.”
“Hempcrete offered an alternative construction which was good for self-building,” Nicklin added. “We like that it can be sourced in the UK and supports small-scale growers, we like that it creates a healthy environment to be in with no off-gassing and its breathable properties, that it sequesters carbon and is ultimately biodegradable.”
According to the Natural Building Alliance, a Colorado-based organization that champions natural building techniques, hempcrete is “a bio-composite building material that is created by coating and mixing particles of hemp hurd (also known as shiv – the inner woody core of a hemp plant) with water and lime and then allowing the materials to dry and harden into a natural insulation material.”
“Like traditional insulation, hempcrete can be the infill material to a wall structure or the insulation material for floors, ceilings, roofs, or windows. When it comes to walls that are framed using studs or heavy timbers, builders can use temporary formwork or permanent, permeable sheathing that is situated around framing to cast monolithic hempcrete walls,” the group explains.
“Molding and casting walls involve a steady process of creating and mixing hempcrete in conjunction with a bucket brigade of helpers pouring, spreading, pressing, or tamping the hempcrete into formwork. Prior to casting and upon being dumped out of a mixer, hempcrete mixes typically look like crumbly oatmeal with no cohesion until builders squeeze and tamp the mixtures. When builders spread and press the mixture in formwork, they typically do it at a depth of four to eight inches at a time. When the formwork is full, the team of helpers can then remove and raise the slip forms for further assembly to complete the wall. For hempcrete installation that goes beyond the framing of one or both sides of the wall, builders can use spacers attached to the slip forms to extend the depth of the wall.”
Nicklin and Mateer began construction on the studio in May of 2020 and completed it last July.
The RIBA Journal said that Nicklin and Mateer “had development in mind when, as project architects with 10 years’ experience at other firms, they bought the bungalow.”
“We were always doing things on skinny little sites so we saw the potential,” Nicklin told the outlet.
The RIBA Journal has more background on the studio:
“A decision taken even before the final form of the building was worked out was to use hempcrete, and the pair have become enthusiastic advocates for the biocircular material. Combined with a timber frame, it provides structure, breathable insulation and fireproofing, and is so easy to use that the architects could draft in equally unskilled friends to help, making for sociable construction. Outside, the vegetal walls are coated in thick gobs of lime render flicked on with a paint scraper and finished with many thin coats of chalky limewash. Laborious but economical, says Mateer, and another pragmatic choice for people with little hands-on building experience. It gives the small building with its overhanging, monopitch roof a soft but weighty character quite distinct from a typical garden shed. Rustic roughness is also melded with some refinement: oak-framed windows – with triangular mullions inspired by a medieval house at the Weald & Downland Museum – are beautifully made, again by the architects. Even so, stepping through oak doors at either end brings surprise.
“Daylight fills the sunken rooms through garden-facing windows, set above built-in bench seating, from which ribbed oak wainscotting extends around the base of subtly textured painted hempcrete walls. Reflections from a pond dapple the soffit of the overhanging roof outside – a deliberate recreation of the effect produced by puddles on the balcony of the couple’s last flat. Small windows in the back wall are placed on the outside face to make the best of the west light.”
The studio is a testament to hemp’s versatility as a material –– whether for building supplies or consumer products. A company in Ohio signed a deal with a processor earlier this year to provide raw material for hemp-based bioplastics.
