Flat House Zero Carbon Farmhouse by Practice Architecture

A crude agricultural shed is slowly undressed to reveal an astounding farmhouse created predominantly from hemp. Designed by London-based Practice Architecture, Flat House is a trailblazing, low-embodied carbon home that champions the use of sustainable and naturally grown materials. It is located at Margent Farm in Cambridgeshire, an organic farm that works with bioplastics, hemp and flax, and practises regenerative farming methods.

Practice Architecture collaborated with Margent Farm to find the site and develop the broader design of Flat House. This partnership also extended to the invention of a new hemp fibre cladding product that was used for the first time on the building. This deep, copper-toned corrugated sheeting is “bound with a sugar-based resin made entirely from agricultural waste,” explains the team at Margent Farm.

Flat House is made up of prefabricated timber-framed panels infilled with hemp grown onsite in the 20 acres of the farm. More specifically, the panels are filled with hempcrete which is a combination of hemp, lime and water. Once dry, they are installed into thick, well-insulated walls that also support the building.

Practice Architecture worked closely with engineers and material specialists to develop these construction methods and remarkably, the main elements were raised into place in just two days.

Through materiality changes, the building transitions from open to closed, light to dark and communal to intimate. A large glazed sunroom moves into an enclosed double-height living space and finally to three cosy bedrooms split over two levels.

Internally the material palette of wood and exposed hemp is simple, yet robust. Warmth emanates through the spaces with timber elements such as ceilings, doors, trims, columns and the staircase balustrade. The exposed hemp walls are tactile, full of character and improve the overall air quality with its ability to regulate moisture in the air.

Although the use of hempcrete goes back to the 1980s, it has almost always been covered up with conventional plaster, paint or render. In Flat House, the hemp composition is the protagonist and directly informs the basis of the architecture.

Flat House is a striking building that demonstrates the aesthetic and large-scale project potential of sustainable hemp-based construction.

The farm and the factory are open for workshops, educational days out and exploration; serving to nurture relationships with designers, wellness experts, engineers, scientists and entrepreneurs exploring the vast potential of hemp.