Hartdene Barns

Location: Edenbridge

Brick Manufacturer: Michelmersh Brick Holdings PLC

Brick Name: Selected Darks

Architect: Nissen Richards Studio

Brickwork Contractor: Surrey Heritage Brick & Stonework Limited

Nine carbon net-zero homes on a former farm site in an Area of Outstanding Natural Beauty: the ambition at Hartdene Barns is considerable, and it is met. Designed by Nissen Richards Studio and delivered by Q New Homes to meet the RIBA Climate Challenge 2030 criteria, this development on the Kent-Sussex border ranks among the most rigorously sustainable housing schemes completed in the UK.

The low-carbon strategy is embedded in the structure from the ground up. Structural insulated panels with glulam beams replace traditional masonry construction, reducing embodied carbon by 40% while allowing a high degree of off-site fabrication. The panels, comprising an insulated core between two rigid facings, create an unbroken thermally efficient envelope around each home, eliminating cold bridging and enhancing the performance of the wider environmental strategy. Glulam beams were specified in place of steel, being both less energy intensive to manufacture and structurally appropriate to the barn-derived forms of the buildings. Ceiling beams use metal web joists, fabricated off-site, which require less timber while providing easy integration of mechanical and electrical services.

Existing concrete from the former farm was crushed on-site and reused as hardcore. New low-carbon concrete was specified where fresh material was unavoidable. Nothing left the site that could be kept and reused within it.

Each home is wrapped in continuous high-performance insulation, reinforced by an internal vapour control layer and air seal that maintains airtightness throughout the envelope. Air source heat pumps handle space heating and hot water. Mechanical ventilation with heat recovery manages air quality without the energy penalty of conventional ventilation. Photovoltaic panels cover remaining electricity demand. During peak winter months, average energy bills are projected at around £40 per month. Future occupants will have no gas supply to maintain or replace.

A whole-life carbon assessment, carried out as a condition of funding by an independent assessor, validates the outcome across the full lifecycle of the buildings. The properties are considered to be between 10 and 15 years ahead of typical UK housing in sustainability terms.

External material choices reinforce the same logic. Freshfield Lane Selected Darks, charred spruce cladding and black standing-seam zinc roofing were all selected for durability and low maintenance as much as for their appearance within the wooded AONB setting. The dark tones of the brick connect the buildings to their surroundings without contrivance, while contributing to an envelope designed to perform without significant maintenance intervention for decades. A material palette chosen with longevity in mind is itself an act of sustainability.

Hartdene Barns does not rely on a single headline technology to make its case. The carbon performance here is the product of layered decisions, taken consistently across structure, fabric, services and materials, that compound into an outcome which genuinely advances what residential construction in a sensitive landscape setting can achieve.