Sustainability Report

Embodied carbon strategies

• The project was not designed around a formal certification such as BREEAM or Passivhaus. Instead, it followed a fabric-first approach informed by the principles of the RIBA 2030 Climate Challenge.
• Embodied carbon was assessed at a high level using approximate quantities rather than full BIM modelling. The figures are indicative and reflect a balance between robust construction, long-life materials, and reduced operational energy over the building’s lifespan.
• Material selection prioritised durability and longevity. Welsh slate was sourced locally and chosen for its durability, low environmental impact, and connection to the site’s geology. Corten steel and Western Red Cedar (used for the front door and panel assembly) were selected for their ability to weather naturally without applied finishes. The emphasis was on materials that age well and last, rather than short-life or heavily processed systems.
• Cladding includes locally sourced Welsh slate, corten steel, and SiOO:X-treated grey Western Red Cedar timber. Ground-floor floors and the hearth are polished concrete by Lazenby. Upper floors use engineered timber flooring by Havwoods, with porcelain tiles by Johnsons Tiles.

Operational perfomance

• The house’s operational performance was measured during its first year of occupation. Total annual electricity use was 9,900 kWh. Based on a gross internal area of 497 square metres, this equates to approximately 19.9 kWh/m² per year. On-site photovoltaic generation produced 5,800 kWh over the same period, reducing net grid demand to 4,100 kWh, or 8.2 kWh/m² per year.
• For context, the predicted SAP regulated energy demand was 3,053.7 kWh per year, equivalent to 6.1 kWh/m² per year. The difference reflects the gap between regulated modelling and real-world use, including appliances, cooking, and occupancy behaviour.
• The RIBA 2030 Climate Challenge target is ≤ 35 kWh/m² per year. Even without accounting for photovoltaic generation, the measured performance remains below this benchmark.

Operational emissions strategies

• The design focused on reducing energy demand through insulation, airtightness, and passive design before introducing building services. Performance and long-term suitability were prioritised over meeting the requirements of a specific accreditation.
• The building envelope is highly insulated and airtight, with mechanical ventilation and heat recovery to reduce heat loss. Heating and hot water are provided by an air source heat pump, supported by a photovoltaic array that offsets a significant proportion of the building’s electricity use.
• All glazing systems were supplied by IQ Glass, including Panorama, Sieger, and Invisio® structural glazing systems, using high-performance structural systems suited to an exposed coastal setting.

Longevity informed the design from the outset. The house was conceived as a long-term home, with durability shaping material and construction decisions.

Slate, corten steel, and timber are intended to age naturally within the coastal landscape. The building is designed to be adaptable, low-maintenance, and resilient, reducing the need for ongoing intervention over time.