Butterfield House Extension by THISS Studio

Innovative Residential Extension with Sustainable Materials

The Butterfield House Extension by THISS Studio redefines small-scale domestic architecture, transforming a typical rear extension into a compelling study in material innovation and sustainable design. Located in Stoke Newington, London, the project demonstrates how thoughtful material choices can elevate everyday residential architecture while reducing environmental impact.

Transforming a Post-War Terraced House

Tasked with reconfiguring the ground floor and adding a rear extension, THISS Studio opened up the post-war terraced home to the garden. The new layout creates a more generous, connected living space for a family of four. Guided by the clients’ commitment to sustainability, the architects focused on material responsibility, ensuring that every element contributed to a low-impact design.

Experimental Use of Porotherm Blocks

At the core of the project is the experimental use of Porotherm clay blocks, traditionally reserved for commercial developments. These precision-engineered blocks integrate structure, insulation, and finish into a single system, eliminating the need for additional linings or insulation. The interlocking design simplifies construction, reduces vertical mortar joints, and significantly cuts down concrete and cement usage.

Internally, exposed blockwork provides a pared-back, expressive finish that complements the existing 1970s brickwork. Externally, bespoke cut tiles highlight the Porotherm blocks’ multicellular structure, adding a subtle decorative element to the rear elevation.

Sustainable and Low-Impact Construction

THISS Studio’s resourceful design approach emphasizes affordability and environmental responsibility. Pine furniture boards, repurposed components, and custom-built joists crafted on-site demonstrate a “do more with less” philosophy. Engineered timber trusses support the extension roof, while large glazing expanses bring natural light into the deep, narrow layout, enhancing openness and visual connection to the garden.

The site, built on a WWII bomb site next to Butterfield Green, required excavation to 6 metres to reach stable clay. A lightweight screw-pile system with a floating concrete slab replaced traditional ground-bearing slabs, reducing material use while solving complex site challenges.

A Case Study in Low-Impact Residential Architecture

Though modest in scale, Butterfield House exemplifies how innovative material choices can support sustainable residential design. By using Porotherm as both structure and surface, THISS Studio demonstrates the versatility and environmental potential of clay in domestic architecture, offering a thoughtful model for low-impact home extensions.

All Photographs are works of Henry Woide