The Built Environment Network

Sustainable Craft On The Cornish Coast

November 26, 2025

Edge O’ Cliff — A House Reborn

By: ARCO2 – Sustainable Architecture

Introduction
Originally built in the 1920s, the old Edge O’ Cliff was a charming but decaying wooden chalet, slowly sliding toward the sea. Its replacement, a modest three-bedroom home, stands as a contemporary, sustainable response to a remarkable location within an Area of Outstanding Natural Beauty, beside a Site of Special Scientific Interest, and along the South West Coast Path near St Ives, Cornwall.

A Design and Construction Challenge
Rebuilding on this spectacular yet inaccessible site meant every piece of the house had to be carried down a steep coastal path by hand — no machinery, no shortcuts. Lessons from dismantling the original chalet inspired a deep commitment to reuse: timber and stone were salvaged, while synthetic materials like UPVC and asbestos were painstakingly removed for safe disposal.

Working closely with ARCO₂ Architects, Umbazi Builders crafted a twin-wall timber frame from locally felled Douglas Fir, supported by minimal pad foundations to protect the fragile landscape. A scaffolded tented roof sheltered the site, allowing on-site air-drying of green timber and maintaining exceptional build quality throughout the long construction period.

A dedicated on-site team and open communication with neighbours and passers-by fostered local goodwill and fascination with the project.

Client Reflection

“Building Edge O’ Cliff was an incredibly enjoyable and rewarding experience. ARCO₂’s balanced, scientific approach turned a site full of risk into a process full of trust and creativity. The result is beyond our expectations; a timeless, low-maintenance home that sits harmoniously within its dramatic setting.”

Performance and Sustainability Highlights

  • Passive design principles with ultra-low energy use
  • U-values <0.3 W/m²K, airtightness 0.22 m³/m²hr @ 50Pa (exceeding Passive House standards)
  • Triple-glazed timber windows (U=0.9 W/m²K)
  • Locally sourced twin-wall timber frame, cellulose insulation
  • Solar thermal & 4kWp PV system, MVHR, and smart controls
  • Low water use systems, AECB Water Standards
  • Ecologist-led landscaping using native Cornish species
  • SAP/EPC: A-rated

Multi award-winning Edge O’ Cliff is a celebration of place, craftsmanship and environmental responsibility; a contemporary coastal home that quietly commands admiration while treading lightly on the earth.

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