It’s a little like The Good Life, only several notches more glamorous. And without Penelope Keith popping in from next door. Savannah Miller is probably best known for her fashion company, Twenty8Twelve, which she runs with her movie-star younger sister, Sienna. At home in the picturesque Gloucestershire town of Stroud, however, she is less fashion maven, more eco-warrior.

Miller, 29, her husband, Nick Skinner, 35, their three-year-old, Moses, and Java, 12, Skinner’s son from a previous relationship, live in a house that could hardly be more eco-friendly. With recycled furniture, lime-based paints, reclaimed wood, chickens in the garden and handmade curtains in the kitchen, the Miller/Skinner home needs only a wind turbine on the roof and a wormery on the patio before ticking almost every green box going.

They bought it two years ago for just £225,000 – a bargain for Stroud, but one with challenges. “It was the most vulgar . . . ” Miller says, tossing back a blonde tress and shuddering, as if she cannot quite bring herself to recall the previously lowly aesthetic state of the place she now calls home. “The woman who lived here moved in when she was four and died here aged 94. There was no central heating or proper plumbing. The whole place was heated by night storage heaters. There were swirly-wirly carpets. All the fireplaces were clad in disgusting fake brick. You couldn’t swing a cat in the kitchen.”

The couple, who previously lived in north Devon, where they met, gutted the house, knocking through the connecting wall between kitchen and living room to make one vast, light space onto which Skinner attached a ready-made conservatory. In terms of refurbishing, what they planned was pretty radical. So radical, indeed, that moving in was impossible.

Where did they live? In a giant tepee on the lawn. “I think the neighbours thought we were new-age travellers,” Miller giggles. “Actually, I only lived in it on weekends, because I was in London most weeks setting up the business with Sienna. Twenty8Twelve had started, so there I was, trying to juggle my first child, a new company and life here in the rubble.” The company name is derived from Sienna’s birthday – Savannah’s, which would have given them Thirty Twelve, “just doesn’t sound so cool”. She clearly does not hold it against her higher-profile sibling, though: the two of them get on “brilliantly”.

Thanks to demand from high-end stores such as Selfridges, Barneys and Neiman Marcus, which now stock their range, Savannah became rather busy. Which meant Skinner, the boys and Sol, the alsatian, were left living in the tepee, using the downstairs loo in the house and showering from a hose rigged up over a giant pit where the conservatory now stands. Moses, then one, had his cot under canvas. Everyone loved it.

As for Skinner’s commitment to eco-building, it sounds terrifically voguish, but he had no choice in the matter. Overexposure to petrochemical-based products, probably during a stint building boats in Italy when he was 18, has made him highly allergic to all such toxins. He is an able builder and carpenter, but only if using the right stuff.

“If Nick even uses a two-part glue, like Araldite, his face blows up like the Elephant Man for two weeks,” Miller says. “I can’t even use nail varnish or wear scent.” So, all nasties such as resin, meths, solvent-based paints and glues were out of the question. Not that this bothered him much. “Once you move into sustainable or traditional styles, it’s fine,” Skinner says. “It’s actually a really nice way of building. It also goes with the history of this house.” (The property was built as two cottages for woodworkers in 1830.)

All the fireplaces were knocked back, their fake brick removed and ancient stone lintels revealed. The original wooden floors were uncovered, sanded and polished with wax. The old furniture was resanded, repainted and effectively reborn. A glass porch was recycled into a greenhouse in the garden. The kitchen was rebuilt using the one from their previous Devon home, with a gleaming range that was bought on eBay for £200.

“And I’m proud of this,” Miller adds, showing off a rather elegant wheeled butcher’s block. “It’s from Ikea. A friend gave it to me, saying she couldn’t bear it.” After it had been sanded down and repainted in duck-egg blue, however, the friend rather wished she hadn’t been so hasty. “She’s furious. She can’t bear how good it looks,” Miller says meekly, smoothing down her denim empire-line smock (Twenty8Twelve, naturally).

Admittedly, if you are blessed with Miller’s visual acumen – she trained in fashion design at Central Saint Martins – you will make even the most terrible home look terrific. The house is light and airy throughout, with simple country style and a lot of flair. She has framed their bed with Balinese white cloths, tied back the bedroom curtains with old boating ropes and decorated the room with flowers stuck in simple jam jars. Her study is painted in fresh white, with a striped blind at the window. Sturdy beams frame the door.

“I got these from a job I was doing for Kelly [Hoppen, the interior-design guru who happens to be Miller’s stepmother],” Skinner says. “They’re a perfect fit.” That was convenient, I observe. “Oh, no,” Miller says. “Nick hoards everything. He saves all his wood in case he can use it at a later date. It’s annoying – our garden is full of old bits of wood. And what’s most annoying is that he will typically find just the right use for them.”

On investigation, the eminently practical Miller clearly married the right chap for this type of job: after his boat-building stint, Skinner lived for several years in Costa Rica, where building houses from scratch is the norm. “All my ideas about eco-building came from there,” he says. “We would pick up wood from wind-felled trees on the forest floor. We would go down with Canadian chain saws and simply build houses.” Any architectural training, then? “No, I learnt all about that on the job.”

It’s also handy that Nick is an eBay whiz. “Look at this copper fire hood,” Miller marvels. We stand looking at it in awe. “Hand-beaten, and it looks as if it was made for this fire – £12!”

The couple estimate that they have spent £50,000 refurbishing the three-bed house, which has a wet room downstairs and a large bathroom upstairs. The rooms are painted either in Farrow & Ball or in lime-based natural paints. Most of the wood is reclaimed – leftovers from Skinner’s building jobs or wind-felled trees. There are quite a lot of skip-sourced elements, too. “Nick cannot walk past a skip without diving into it,” Miller says proudly. She may be the sister of a celebrity, but she certainly doesn’t only rate things from a first-night goodie bag.

What were their main concerns in rebuilding the house? “Everything had to pass through a filter of environmental factors, the character of a period house, selling on and price,” Skinner says. Money, though, was the most important issue, and the only reason they haven’t put solar panels on the roof. “I think economic concerns are the case for everyone,” Miller says. “Which is why eBay is so brilliant. It means you can afford to do things like get your wallpaper from Neisha Crosland.” She points sheepishly at the gorgeous floral paper in the kitchen.

As if he hadn’t done enough to the house, Skinner also remodelled the garden. Rather than put it in landfill, he carted the rubble from the house to level off a steep incline and create a series of stepped terraces. Below the vegetable patch is crazy paving (again, from reclaimed slabs), a chicken coop and a playhouse halfway up a tree.

The couple were going to sell on immediately, but now will probably wait two years or so; Savannah is expecting a second child in June, and seems less than keen to have an infant crawling around rubble again. Will their next home be as arduous in its construction? Probably more so. Their big idea is to build an environmentally sound, carbon-neutral house from scratch. In a woodland. Costa Rica? Wales, actually.

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