The Gorgeous Walls in This London Kitchen Renovation? That’s Hempcrete

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Project Details:

Location: London, United Kingdom

Architect: Cairn / @cairnarchitects

Footprint: 750 square feet

Builder: David Sheard Ltd

Structural Engineer: Structure Workshop

Cabinetry: Xylo

Photographer: James Retief / @james_retief

From the Architect: "House Made By Many Hands is one of the first building structures in the U.K. to specify a low-carbon limestone calcined clay cement (LC3) concrete, a new material which generates 30 to 40 percent less CO2 in its production than standard Portland cement. Commissioned by an environmentally conscious client, the compact Victorian house renovation has been a testbed for LC3, a product which has the capacity to reduce total global CO2 emissions by one to two percent if adopted universally by the construction industry. The project demonstrates how a Victorian house can be renovated and extended with a substantially reduced environmental impact—40 percent lower than a typical build deploying conventional concrete, steel frame box, and plasterboard.

"Located on a densely-inhabited, car-free street, the two-story terraced house occupies a constrained site with no back garden and only a thin strip of external space. As found, it was dark and cramped. The challenge was to work with what was there, designing as sustainably as possible through reuse and repurposing of existing materials to bring it up to modern day standards, creating a homely and productive new kitchen for its owner, a chef with a background in sustainable agriculture.

"An explicit strategy of reuse underpins the whole project. Adopting a fabric first approach, identifying what was essential, retaining usable original elements, constructing cautiously and interweaving old and new, have been fundamental to the project. Rather than overhaul the servicing of the house, interventions have been simple and low-tech, selectively using what was found (relocating the combination boiler rather than consigning it to a skip), supplemented with energy-saving strategies such as double-glazed windows.

"Client and architect were committed to repurposing and, where new materials were necessary, bio-based materials—hempcrete, cork, wood fiber, wood wool, and lime plaster—were specified, to improve health and wellbeing benefits. Lining layers have been omitted where possible, revealing structure and frames so that the new hardwood timber frame forms a key visual component of the ground floor spaces. Where boards were installed, breathable wood wool was used finished with lime render, and the new kitchen worktops by Foresso are made of recycled waste wood products. The result is an airy home with warmth and earthy textures, where old and new blend, celebrating the patina of time.

"The ground floor renovation places the new spacious kitchen at the heart of the house. The floor has been lowered to improve head height and the space benefits from improved connections to the living room and clearer sight lines and access to outside spaces. Upstairs improvements have been made with a renovation of the home office, which now has access to a roof terrace.

"LC3 technology was developed in Switzerland at EPFL, along with experts in Cuba and India. Concrete made with LC3 looks like conventional concrete and it is mixed and poured in the same way, requiring no additional site training. It has been used here in the floor slab; it was also used to underpin the house’s existing brick footings to gain height in the extension."