A once-derelict medieval chateau in the foothills of the Pyrenees recreated as a stylish holiday home

When Adrian first saw it, he remembers that “it was in a dreadful state, and it wasn't a very attractive building at that point.” With the exterior covered in a depressing grey render that concealed the stonework, rotting floors, holes in the roof, a single rat-infested bathroom and no functional plumbing or electricity, it didn't have a huge amount to recommend it. “It was immensely cheap, though," explains Adrian, "so I thought I'd make a silly offer. I didn't tell my wife beforehand, but if she hated it I knew I could always do it up and sell it on.”

Adrian's wife Genevieve did not take to it at first, perfectly understandably, but the beautiful setting in the foothills of the Pyrenees was a draw, and Adrian had a vision of how it could look. It wasn't their first time embarking on a major renovation project – when they bought their house in the UK in the early 1990s it hadn't been touched for 60 years, so they were accustomed to living with builders – but this was going to be a big one by anybody's standards. “I thought we would be able to move in after around 18 months,” says Adrian, “but it turned out to be five years.”

Adrian masterminded the entire project with the help of an architect, rearranging floor plans, creating a vast and beautiful entertaining space in the old agricultural building that adjoins the original house, and designing a new pool house inspired by the mountain huts of the region. It was a daunting project: “at one point you could see all the way from the bottom through to the daylight coming through holes in the roof,” Adrian remembers. “The walls were crumbling, and when we started work on one of the towers, it just fell down. There was dry rot, wet rot – really any problem that you can imagine, it was there. Effectively, we rebuilt it.” A building of this age in Britain, of course, would be Grade I listed and it would be extremely difficult to make changes, but the relative freedom in France meant that it was all fairly straightforward.

There were a few interventions that made an extraordinary difference to the house's appearance. One was removing the grey render from the outside and repointing the golden stone beneath, and another was retiling the roofs, using slate for the main building and clay canal tiles for the rest, and another was adding windows to the first floor of the barn wing of the house, which made it a perfect candidate for a huge sitting room. Adrian also removed a building that had linked the main house to the guest cottage next door – “it was the most hideous, higgledy-piggledy thing imaginable” – and added a first floor terrace that opens off the main bedroom. Painting the shutters a cheerful sky blue was a final touch that enormously improved the house's appeal.

Inside the house, they took the plaster off the ceilings to expose the beams, giving the rooms a pleasingly rustic feel, and removed flimsy partition walls to open up the floor plan, especially in what is now the main bedroom, which had been divided into three different rooms. “Smashing those down was one of the most enjoyable things I've been involved in,” says Adrian. They were determined that the interiors should feel informal and relaxed, as befitted the building, and embraced the traditional lime render on the walls, which allows the stone beneath to breathe. The long renovation meant that they had plenty of time to gather furniture, and picked it up wherever they found it in English flea markets and French brocantes. “Nobody wants big furniture,” reflects Adrian, “so where we needed to buy big things to suit the scale of the rooms, it was wonderfully affordable.”

The house has been very much a family affair, with various relatives coming out for the summers to help out with the renovation, including Adrian and Genevieve's three children. Their daughter, India Holmes, formerly Design Director with De Gournay and now running her own rug company, Pelican House, has added her own designs to the house, while paintings of textiles by Genevieve's grandfather adorn the walls. Since it was finished, the château has played host to plenty of parties (including India's 21st), but also serves as a place for the family to retreat and enjoy the great outdoors for as much of the year as possible.