A dream eighteenth-century house in Bath restored by designer Patrick Williams

It was just four years ago that we featured designer Patrick Williams' flat in Wapping, which, though small, seemed a feat of a project - such was the level of detail. Patrick went to great lengths to ensure nothing jarred with the nineteenth-century fabric - even decanting his toothpaste into white artist's paint tubes. He has since had two little girls - Wren, four, and Bonnie, 18 months - with his partner Neri, bought an eighteenth-century house in Bath and undertaken the huge project of transforming it into their family home with equal gusto, imagination and sensitivity - minus the decanted toothpaste and with the addition of Peppa Pig paraphernalia thrown into the otherwise harmonious mix.

Both Patrick and Neri grew up in one place and wanted their children to do the same, but with a baby on the way, their flat in Wapping was not going to provide that. Neri, a good cook, had always dreamt of running a B&B and they started looking for a rural idyll near Bath. Then, when Wren was just two days old, Patrick got a call from an estate agent to say a building was coming up for sale that he needed to see. He jumped on the train immediately and made an offer on the door-step. This Georgian town house in Pierrepont Place in the centre of Bath was built in 1748 by John Wood the Elder as part of his original town-planning scheme. Owned by the Freemasons, it had not changed hands since 1809; next door is the Masonic hall. It was in a pretty terrible state, with offices downstairs and student digs upstairs, but was the sort of project Patrick could not resist.

He admits to totally underestimating what needed to be done. 'You would have needed X-ray eyes to see through the five layers of lino,' he says by way of excuse. To begin with, while waiting for the results of planning applications, the family camped in the house, but it soon became apparent it was not the place for a tiny baby. When they moved out and work began, they realised the floor beneath the bath they had used daily was so rotten it was held up only by the coving of the ceiling below. 'Each day of the project brought good or bad news,' says Patrick, who lived there alone for 18 months, in often very cold conditions, while Neri and Wren stayed with family. But the fact that the building had had little love was, in some ways, its saving grace. As Patrick says, 'It's much cheaper to add another layer of lino or plasterboard than it is to remove the existing fabric.' Much of it had remained, as had all the original vellum documents dating from the time it was built.

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The house is set over five floors, with two bedrooms in the basement for the B&B guests, the kitchen on the ground floor, the library (and what is soon to become the prettiest panelled playroom) on the first floor, Neri and Patrick's bedroom and bathroom and a family bathroom above, and the children's bedroom at the top.

For Patrick, whose company Berdoulat specialises in the restoration and reinvention of period buildings, 'the building itself is the most important client and should dictate what is done to it'. Such is his respect that he did not begrudge the request from the local conservation officer to preserve the original peg joints between the floor joists and beams, even though new steel sections would provide the structural support - a detail that, once covered by floorboards, nobody would see. He delights in the 'hidden beauty' of the building - details like the pie-crust-edged chimneypots that 'can be seen only by Father Christmas'.