Grand Designs success shines spotlight on Welsh timber innovators

A Welsh firm that designs and builds with home-grown timber has received high praise after pulling off the most successful project in Grand Designs history.

Unnos Systems, named for the Welsh Tŷ Unnos or ‘a house in one night’, collaborated on the home in Southwater, West Sussex that featured in the 8 October episode of Grand Designs.

Presenter Kevin McCloud called the modular home: “The first project to deliver all three — on time, on budget, and with high quality.”

Quality 

The precision-engineered modular timber dwelling was designed and manufactured by Unnos Systems, with architecture by collaborators Koto.

Commissioned by Pete and Aey, who wanted a sustainable home that fit into the surrounding landscape, the dwelling was constructed in Wales over a seven month period before its transport to the Sussex site.

Unnos’ process of building in a controlled factory environment rather than at the final site protects components from the elements. It also saves time as groundwork and superstructure build progress simultaneously.

For the Southwater project, five fully finished volumetric modules were fully manufactured at Unnos’ warehouse over a number of months, and installed in one day.

Once the modules arrived, the near-complete home landed on the finished site with none of the disruption, mud, or inefficiency of a standard build.

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.”

McCloud also praised the process as cost-effective, saying: “It’s all about containing costs. Having it prefabricated in a factory in Wales, brought in on lorries, costing exactly what you thought it would. That is the future of Grand Designs. It’s the future of self-build.”

Sustainability 

Pete and Aey’s home was built from locally sourced Welsh timber seasoned in a biochar-powered kiln, which is itself powered by timber waste from previous Unnos production.

Combined with passive-level airtightness, MVHR ventilation, and the option for solar and battery integration, the home achieves high energy efficiency and near self-sufficiency.

Kenton Jones added: “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.”

Unnos Systems’ story began over four decades ago in a small workshop above a cowshed on the Jones family farm in mid Wales.

The company first became known for joinery, bespoke furniture, and a royal commission at Highgrove House for the then-Prince of Wales.

This foundation of craftsmanship evolved through partnerships with Coed Cymru and the Welsh School of Architecture, leading to the development of engineered Welsh timber systems, and ultimately to Unnos Systems’ award-winning modular housing.

Unnos’ homes have also been featured on Channel 5’s ‘Build Your Dream Home in the Country’.

The Grand Designs episode Southwater 2025 is available to watch on Channel 4 on demand now. To find out more about Unnos Systems, visit their site here.