# Clay Block Home Extensions
Butterfield House Extension Uses Exposed Porotherm as an Addition

By Amy Duong | Published 2025-12-02 | Art & Design
Source: Trend Hunter, https://www.trendhunter.com/trends/butterfield-house-extension
References: [thiss.studio](http://thiss.studio/)

![Clay Block Home Extensions](https://cdn.trendhunterstatic.com/thumbs/591/butterfield-house-extension.jpeg)

The Butterfield House Extension uses exposed Porotherm for a compact upgrade by replacing the rear of a London terrace with a structurally efficient clay-block volume designed by THISS Studio. The single material serves as structure, insulation, and interior finish, creating walls that remain visible rather than being covered with plasterboard. The blocks align with the tone of the original brickwork while providing improved thermal performance and reducing construction layers. Large sliding glass doors open the ground floor to the garden, allowing natural light to counter the visual weight of the clay surfaces and brighten the deeper parts of the plan.

The extension sits on a screw pile foundation with a raised slab that minimises excavation and protects the site’s existing ground conditions. The layout adds a larger kitchen and dining area with a clear distinction between new and old construction. Joinery and flooring are kept minimal to highlight the blockwork, and the compact footprint is organised to improve circulation through the home

Image Credit: Henry Woide