Low Energy Coastal Architecture in Cornwall: Lessons from Turnstones
Sustainable architecture in Cornwall has to do more than reduce energy use. It must respond to exposed coastal conditions, changing weather patterns, site sensitivity, material performance, long term maintenance and the wellbeing of the people who will live in the home every day.
At ARCO2, low energy design is considered from the earliest stages of a project. It influences orientation, layout, construction methods, insulation, glazing, ventilation, heating systems, material choices and the relationship between a building and its landscape.
Turnstones, a contemporary sustainable home overlooking Polzeath Beach in North Cornwall, demonstrates how these principles can come together in a highly efficient coastal dwelling that balances architectural quality with environmental responsibility.
A Sustainable Replacement for a Poorly Performing Bungalow
Before Turnstones, the site was occupied by a damp, inefficient and poorly performing 1960s bungalow that had deteriorated after decades of exposure to the coastal environment. It no longer met the needs of the family or the expectations of modern sustainable living.
The replacement home was designed as a low energy, passive house inspired coastal retreat for multigenerational living. It needed to provide comfort, accessibility, durability and exceptional environmental performance while making the most of its elevated position above Polzeath Beach.
The result is a contemporary coastal home that combines architectural ambition with measurable sustainability outcomes.
Performance Led Design from the Start
The environmental performance of Turnstones reflects the depth of thinking applied throughout the design process. The house achieved an air pressure test result of 0.90 m³/h·m² at 50Pa, an excellent achievement for a building with complex junctions involving masonry, concrete, steelwork and timber construction.
The project also achieved an embodied and operational carbon figure of 412 kgCO2/m², meeting the ambitious RIBA 2030 carbon targets and performing significantly better than the 2020 best practice benchmark of 500 kgCO2/m².
Operational energy demand is approximately 50kWh/m² per year before the contribution of solar panels and battery storage. By comparison, a typical UK home uses around 140kWh/m² per year.
These figures demonstrate that sustainable architecture is not simply a design philosophy. It can be measured, tested and verified through careful design decisions and high quality construction.
Super Insulation, Airtightness and Triple Glazing
Turnstones follows a fabric first approach to sustainability, reducing energy demand before relying on technology. The walls were constructed using a traditional cavity system with a super wide 300mm insulated cavity and specialist basalt wall ties to minimise thermal bridging.
The roof, floors, glazing and external doors were all designed as part of an integrated performance strategy. Triple glazed windows improve thermal comfort while airtight construction significantly reduces unwanted heat loss and draughts.
This creates a home that requires very little heating throughout the year. In exposed coastal locations where wind and driving rain can affect comfort, this level of performance is particularly valuable.
Healthy Indoor Air and Comfortable Living
Sustainability should enhance the living experience, not compromise it. At Turnstones, a mechanical ventilation system with heat recovery continually supplies fresh air while retaining warmth within the building.
This helps maintain excellent indoor air quality and provides a healthy, comfortable environment throughout the year. Combined with abundant natural light and carefully designed living spaces, the result is a home that feels calm, uplifting and easy to live in.
For the family, sustainability is experienced through comfort, wellbeing and simplicity rather than technology alone.
Ground Source Heating, Solar Panels and Battery Storage
A ground source heat pump provides highly efficient heating and hot water, significantly reducing the home’s reliance on fossil fuels. The property was also designed to incorporate solar panels and battery storage, further improving long term environmental performance.
Because the building fabric is already highly insulated and airtight, heating demand remains exceptionally low. This allows renewable energy technologies to operate more effectively and efficiently.
This approach reflects a core principle of sustainable architecture in Cornwall. The building itself should perform exceptionally well before renewable technologies are added.
Low Carbon and Carefully Selected Materials
The construction strategy for Turnstones focused heavily on reducing embodied carbon. Materials were selected not only for performance and appearance but also for their sourcing, processing, transportation and long term environmental impact.
The concrete raft incorporated locally manufactured secondary aggregate from the Cornish clay industry and was protected using a 100% recycled damp proof membrane. Engineered timber I joists were selected for their strength, efficiency and reduced material demand, while responsibly sourced timber was used throughout the project.
Other materials including zinc rainwater goods, glulam beams, recycled membranes, insulation products and OSB boards were chosen for their durability and environmental credentials.
These decisions demonstrate how sustainable architecture is often the result of hundreds of smaller choices working together to reduce environmental impact.
Wildflower Roofs, Biodiversity and Water Management
The wildflower roofs at Turnstones contribute both visually and environmentally. They help soften the building within the landscape, create valuable habitat for bees, butterflies and other pollinators and reduce rainwater run off during periods of heavy rainfall.
The green roof above the parking area also conceals vehicles from key views and helps the building sit more comfortably within its coastal setting. At Turnstones, landscape and architecture were designed together rather than treated as separate disciplines.
A Phase 1 Ecology Survey informed the design process, helping ensure biodiversity improvements were delivered alongside the wider sustainability objectives of the project.
Designed to Meet RIBA 2030 Carbon Targets
Turnstones was designed with long term carbon performance at its core. Its lifecycle embodied carbon totals 326 kgCO2/m² and reduces even further when carbon sequestration is included. These figures demonstrate how early design decisions can have a significant impact on the overall environmental performance of a building.
For homeowners commissioning high quality residential projects in Cornwall, sustainability is increasingly about more than energy bills. It is about creating homes that are efficient, resilient, responsible and future ready.
Turnstones shows how contemporary architecture can successfully combine low energy design, carbon conscious construction and exceptional coastal living.
Sustainable Architects in Cornwall
Turnstones reflects ARCO2’s wider approach to sustainable architecture in Cornwall. The project brings together low energy design, carbon conscious construction, biodiversity enhancement, accessibility, comfort and coastal resilience within a carefully resolved architectural response.
As experienced architects in Cornwall, ARCO2 designs homes that respond intelligently to landscape, climate and the people who will live within them. Explore the full Turnstones project to discover how sustainable design principles were applied on a challenging coastal site in Polzeath.
Planning a sustainable home project in Cornwall?
ARCO2 Architecture works with clients across Cornwall to design low energy homes that combine architectural quality, environmental responsibility and exceptional living environments. From passive house inspired coastal homes to highly efficient contemporary dwellings, our team helps clients create buildings that perform beautifully for decades to come.
Contact the ARCO2 team to discuss your sustainable home project.
