When designing buildings at their practice Jones Architects Studio, Russell Jones and his partner, Duygu Kirisoglu Jones, consider three things in equal measure: site, design and nature. This came in handy, then, when the couple became their own clients five years ago, after scoring an early 18th-century farmhouse in the Brecon Beacons National Park. While they knew exactly how to tackle the project together, the challenge was balancing a sensitive restoration with a contemporary extension that would afford them spectacular views of the countryside and mountain peaks of Pen Y Fan and Corn Du.

They began with thorough research at St Fagans National Museum of History, in order to discover how best to honour the historic Welsh architecture and the local vernacular. Peeling back layers of past alterations and modifications, Russell and Duygu revealed the original fabric of the building, with a couple of surprises along the way. They were careful not to create something that would jar with its surroundings, and the completed project is architecturally distinct yet complementary to its original form. As their home comes on the market, Russell and Duygu speak about the fun of transforming a traditional farmhouse and the beauty of the Welsh countryside.

Russell: “My family is from the mountains of north Wales, so when we came to buy, we were always drawn to the rural landscape. As architects, we were looking for something that needed renovating and was going to be a little bit of a challenge. That’s when we found a collection of 18th-century farm buildings in the Brecon Beacons National Park that had been derelict for years.”

Duygu: “It was very unloved, but what might look discouraging to many people looked like a very exciting adventure to us. Then we got started.”

Russell: “We wanted to do an authentic restoration that would bring the farmhouse back to its historic roots. We did research at St Fagans National Museum of History in Cardiff, which is a fantastic open-air museum on the architecture, lifestyle and culture of Welsh people.

“First of all, we removed any evidence of previous work to the building: we took out the cement renders, ugly concrete floors and plastic flooring and windows. We then cast the walls in lime plaster and reinstalled the oak beams.”

Duygu: “When stripping back the layers of the house, we discovered a lot of hidden things, like a pit in front of the fireplace, where the old farmer would have kept chicks and lambs warm.”

Russell: “Once we found the pit, we were very careful to restore it. We added a metal plate that sits over the top of it, which can be lifted at any time. We also discovered an original fireplace and a little window upstairs.

“The configuration of the old building didn’t really include a living room, and the original house was quite dark inside, without any views of the mountains. To fill the space with light, we added a rear south-facing extension. We didn’t want to just bolt it to the house – instead, we have created glazed corridor that links between the two.”

Duygu: “The old and new buildings are very different, both inside and out: the concept, colours, materials, feeling, light – everything is a big contrast. When you move from one to the other, you really feel that change.”

Russell: “There’s a Scandinavian feel to the extension. It has huge window that looks straight at the mountains, so it’s light and airy. You don’t need a fireplace because it’s well insulated and gets plenty of sun. We used finer, more sophisticated materials, such as smoked oak for the flooring, whereas in the old house it’s all lime render and dark colours – whatever materials would have been found around the farm.

“We also planted 2,000 trees in our field, which we did in conjunction with the Wildlife Trust. We’ve been working with the national park on the conservation of pine martens and red kites. Whoever comes here can enjoy the nature, peace and serenity.”

Duygu: “The restoration has been really fun to work on because every element in the house tells a different story. It’s very challenging to try and make an old house feel like it did 300 years ago and be comfortable for modern life, but that’s what we have tried to achieve.”

Russell: “But we could also experiment. For instance, all the staircases we’ve got in the extension are all folded steel plates. We wanted them to be minimalist, using a single material that is easy, affordable and simple.”

Duygu: “We’ve worked together for a long time, so collaborating comes very naturally to us as we share a special architectural language. One of the biggest challenges with a client is understanding their brief and lifestyle and then designing something based on that. In our case, it was very easy because we knew exactly how we live and what we like.”

Russell: “We wanted was to show people that you can live a modern sophisticated life in an old house; that you can recycle, reuse and be sympathetic to the historic part of an old building, while creating something new.”

Duygu: “It’s going to be quite sad leaving because it’s been an amazing home to us and such an exciting place to live. The connection with nature here, we think, is quite unlike anywhere else. The environment is ever changing because of you really feel the seasons. Let’s just say that it’s never boring.”