A Welsh company specializing in sustainable timber construction has earned widespread recognition after completing what host Kevin McCloud called the most successful project in Grand Designs history. Unnos Systems, whose name derives from the Welsh term "Tŷ Unnos" meaning "a house in one night," partnered with architecture firm Koto to create a revolutionary modular home in Southwater, West Sussex, featured on the October 8 episode of the popular British television series.
McCloud praised the precision-engineered modular timber dwelling as "the first project to deliver all three: on time, on budget, and with high quality." The home was commissioned by Pete and Aey, who specifically wanted a sustainable dwelling that would blend seamlessly with the surrounding landscape. Rather than building on-site, Unnos Systems constructed the entire structure in their Welsh facility over a seven-month period before transporting it to the Sussex location.
The innovative construction process involves building in a controlled factory environment rather than at the final destination, which protects all components from weather damage and significantly reduces construction time. As Kenton Jones, founder of Unnos Systems, explained: "When our buildings leave the factory, they're fully protected and have never seen rain in any of the layers. The precision and quality from a factory environment is very difficult to achieve on a site build."
For the Southwater project, five fully finished volumetric modules were manufactured at the Unnos warehouse over several months and then installed in just one day. Once the modules arrived at the site, the near-complete home was positioned on the prepared foundation without the typical disruption, mud, or inefficiency associated with traditional construction methods. McCloud highlighted the cost-effectiveness of this approach, stating: "It's all about containing costs. Having it prefabricated in a factory in Wales, brought in on trucks, costing exactly what you thought it would. That is the future of Grand Designs. It's the future of self-build."
Sustainability stands at the core of Unnos Systems' approach, with Pete and Aey's home constructed entirely from locally sourced Welsh timber. The wood is seasoned in a biochar-powered kiln that runs on timber waste from previous Unnos production, creating a closed-loop system. The dwelling also features passive-level airtightness, MVHR (Mechanical Ventilation with Heat Recovery) systems, and options for solar panel and battery integration, achieving remarkable energy efficiency and near self-sufficiency.
Jones emphasized the company's environmental mission, adding: "We're proving that high performance and low impact can coexist, that sustainable timber buildings can be stronger, lighter, and far more efficient than masonry alternatives." This philosophy reflects Unnos Systems' commitment to demonstrating that eco-friendly construction doesn't require compromising on quality or performance.
The company's journey began more than four decades ago in a small workshop located above a cowshed on the Jones family farm in mid-Wales. Initially, Unnos Systems gained recognition for joinery work, bespoke furniture creation, and notably, a royal commission at Highgrove House for the then-Prince of Wales. This foundation in traditional craftsmanship gradually evolved through strategic partnerships with Coed Cymru and the Welsh School of Architecture, ultimately leading to the development of advanced engineered Welsh timber systems and the award-winning modular housing solutions the company produces today.
Unnos Systems has gained additional television exposure through appearances on Channel 5's "Build Your Dream Home in the Country," further establishing their reputation in the sustainable construction industry. The Grand Designs episode featuring their Southwater project, titled "Southwater 2025," is currently available for viewing on Channel 4's on-demand service, allowing viewers to witness the innovative construction process firsthand.
