Cork Loft
A loft extension built almost entirely from cork, one of the most sustainable materials available, which redefines what a loft can be and proves being green doesn’t need to be grey.
Before the renovation, the house had not been touched for decades. It was dark, damp, and affected by mould. Determined to transform it, Quentin and Anaïs wanted a design that placed sustainability at the heart of the project. The loft extension marks the first phase of a larger masterplan that includes a full retrofit, external insulation, and a ground-floor extension.
Cork was chosen by Office S&M Architects for its environmental and material properties. Harvested from the bark of cork oak trees without felling them, cork enhances biodiversity, sequesters carbon, and is biodegradable and recyclable. It offers excellent thermal and acoustic insulation, is lightweight, and requires little maintenance due to its natural properties.
Its harvesting process is regenerative, when the bark is stripped, the tree continues to absorb CO₂ and the entire material is used. The sheets are formed without synthetic glues, relying instead on the cork’s natural sap to hold the granules together. Widely used in Portugal andSpain, cork’s versatility extends beyond construction to products, fashion, and, of course, wine stoppers.
Office S&M Architects explored how far cork could go. Through detailed research they found it could replace many standard construction materials. In this project, cork has been used as external cladding, insulation, flooring, and even as aggregate in the render. Its lightweight properties made it ideal for a loft, where materials must be transported and supported by existing Victorian foundations. Cork’s durability, resistance to moisture and mould, and longevity make it an excellent building material.
“Cork Loft has been a unique opportunity to explore the incredible potential of cork in architecture. It’s a material that’s sustainable, affordable, and full of character – proof that being green doesn’t need to be grey.”
While most lofts blend quietly into their roofs, this project celebrates contrast. The extension respects the proportions of the Victorian roof while asserting its own identity. Initially, the cork’s dark brown tones echo the surrounding slate roofs, but as it weathers, a pattern emerges, blending with the brick and mortar below.
Like many natural materials, cork changes over time. Exposure to sunlight, wind and rain cause the colours to fade. Through prototyping with Materials Assemble, Office S&M Architects choreographed this natural transformation, creating a façade that gradually changes. Panels treated with UV protection fade at different rates, revealing a pattern inspired by World War II dazzle ships.
Externally, joyful yellow accents are used to highlight details such as rain watergoods and window frames. Inside, the two tones of cork laid in a striped pattern, continue through the bedroom and stairwell floors. The yellow continues upward, guiding the eye through the stairwell and bringing warmth and light to the core of the home.
Film is a shared passion for Quentin and Anaïs, and this influence appears throughout. A rectangular window frames the garden like a cinema screen, while a circular window in the shower offers playful, porthole-like reflections. Above the shower, a frameless rooflight opens to the sky creating an ‘infinity shower’.
Cork Loft demonstrates how versatile cork can be, and how sustainability can be imaginative, beautiful, and bold.
Details
Location: Walthamstow, London
Project Type: Residential loft extension
Client: Quentin and Anaïs
Cost: £1,950/m2
Team
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