The closest word in English is cosy, but that has a slightly frumpy association – as in a beloved old cardi, which is lovely to snuggle up in, moth holes and all, but you wouldn’t wear out in public.

We all like being cosy (I’m wearing a down gilet as I type, in pursuit of it on a rather damp spring day), but it’s a bit of a guilty pleasure – and it certainly has nothing to do with being cool. Not in temperature terms, but as in effortlessly groovy. Cool like Steve McQueen, or the young Jane Birkin.

So what struck me immediately on entering Amy Maynard’s brilliant space, a two-bedroom love shack in the garden of her house in the village of Appledore, on the northern fringe of Romney Marsh, is that it is both of those things in one.

A really cosy gaffe where you could settle down in woolly socks, with someone special and a glass of Malbec, your tummy full of mac and cheese, the wood stove humming and give Netflix a good going over – but feel really cool while you did it. It even has a cool name: The Outbuilding.

One of the tick boxes on their house search list, when Amy and her husband Charlie and two young children decided to make the move out of London four years ago, along with being close to Amy’s parents and on the right side of the county line for Kent’s grammar schools, was: “Somewhere with room to create something that would make an income.”

The house they bought, once the village store on Appledore’s main (practically, only) street ticked them all with, as Amy explains, “a garage and workshop just begging to be converted.” Which was a seriously good result, considering it was only the second property they looked at.

With years of experience as a journalist specialising in lifestyle subjects, including interiors, Amy had a very good idea of the kind of look she wanted for the project. However, feeling there was much to gain from some professional help, she engaged architect Rob Pollard of RX Architects in nearby Rye to help her get the most out of the space. “We had a long chat and I told him the feel I wanted – warehousey, not twee.” Amy then contacted builder Ryan Blake of Blakes Building Solutions, “he shared my vision and was absolutely amazing,” she remembers.

And there it is – exactly what makes The Outbuilding so groovy from the moment you walk into the surprisingly large space of the living area. The ceiling is vaulted right up to the rafters, there’s a wall of Crittal-style black steel-framed windows opening onto the decked terrace and bare old bricks on the two flanking walls.

It’s got the full ‘easy like Sunday morning’ (if you remember that seminal 1980s ad… if you don’t, you can Google it) loft-living vibe.

Those bricks are original (although Amy did limewash them to make them look consistently aged) – and at one point they were the only walls left standing. Everything else was rebuilt from scratch.

The outside is weatherboarded in keeping with the local vernacular, painted in Farrow & Ball’s lead grey, Downpipe, with white window frames in the New England style. “There’s a lot of white and silvered wood weatherboarding in the locale, I wanted to do something a bit different.”

Once you step through the matt black front door, with its matt black knocker, all the other walls of the living area – the kitchen, dining area and sitting room in one – apart from the bricks are white, contrasting with the Shaker-style kitchen, which is painted in the blue-black of F&B Railings, with simple brass knobs.

The kitchen tap is also brass, the worktop marble-effect quartz – and this combination of black, white, brass and notes of warmer colours is a theme throughout the building.

The warm touches in here come from the bare brick, which is picked up in the terracotta pink stripes in the fabulous linen curtains by Canterbury-based company Ada & Ina. Which, I note, are hung from very chic concealed tracks – perhaps the kind of thing it takes one interiors feature writer to install and another to notice. It was a YES from me.

Also warming up the industrial chic coolness in here, are all the charming vintage pieces which Amy has assembled to furnish it. The décor style may be bang up to the minute, but none of the furniture or accessories in it are new. Not a single thing.

“We spent the money on the building, the bathroom and the steel-framed doors – which are from The Green Window Company – so everything else had to be done on a budget and a large proportion of the furniture and accessories are secondhand.

“I spent the six months the building took to convert sourcing all the things to go in it, which I loved doing. I found them on eBay, Gumtree, charity shops and at Ardingly Antiques and Collectors Fair… The kitchen table was from St Michael’s Hospice furniture shop in Tenterden. The sofa was £250 on eBay…”

More of Amy’s ingenious bargain style-solutions can be seen on the walls. “I went to Rye Old Books, which is a lovely second-hand bookshop, and found old books with beautiful coloured plates inside. I sliced them out and had them framed. I did feel bad cutting the books up, but at least the pictures get seen now.”

A group of paintings on the top shelf of the wall of shelves on the internal wall – on which the books are gloriously arranged by colour – were also frugally sourced, mainly from eBay, and are very effective as a group on a theme of domestic still lifes.

A cupboard on the same wall opens to reveal a concealed telly and to the left of it is another black steel multiple-paned window, through to the bedroom – which Amy wanted specifically to create that loft feeling. It works brilliantly and also makes the bedroom very light.

But to get in there, you must first step back into the relative darkness of the hall, painted the gorgeous rich dark Studio Green (also F&B) – and it is these changes in pace that make this really quite compact space work so well.

This is especially true as after about two footsteps the hall segues into also being the second bedroom. It has two built-in bunk beds, painted the same green, so appealing you can practically hear the squeals of excited children leaping onto them. I’m having the top bunk, by the way. “The bunks were the architect’s idea, with the ceiling lantern for light. I wanted it to be like a train or a boat, so I bought the two fish-eye mirrors, to give the effect of portholes.”

Also on the wall in this space is an old printer’s tray, once used to store metal type, into which Amy has put some letter cubes, which prove to be irresistible to guests, be they loved-up couples seeking solitude, or families with young children wanting walks and beaches (it’s 20 minutes to the coast). “People leave us lovely messages in it. One said: ‘I never want to leave’.”

I felt like that about the next room along on its own – a bathroom of size in opposite proportion to its splendour. It’s small but absolutely perfect.

In the same combination of matt black, white, brass and spots of feature colour, the shower screen is Crittaly-style from WC1 Bathrooms. The giant shower head is brass, the drain, towel hook and soap holder are matt black. “I don’t like matchy matchy,” says Amy.

But she clearly does like a theme and it works fantastically throughout The Outbuilding, bringing the whole scheme together. The marble seen in the kitchen is visited here in the fabulous oblong basin, which sits on a black metal stand, with a splendid brass tap and a round brass mirror above. “I bought the sink on Amazon and had the stand custom made.”

Above it is a splashback of glorious jade green tiles by Best & May. “They’re very expensive, so we just had a few.” The tiles are arranged in a herringbone pattern – as are the shiny white ones in the shower, with smart dark grey grout – which echoes the herringbone of the oversized wood parquet throughout the rest of the building. The bathroom floor is laid with small hexagonal tiles.

On the wall are more framed plates from old books, these ones drawings of shells. But while the bathroom is incredibly chic and would not be out of place in a designer Manhattan apartment, just to the left of the sink is a floral curtain, hiding the washing machine and dryer and adding that balancing touch of cosy.

The main bedroom when you do get into it has another atmosphere again, adding a different texture to the whole. Painted a lovely pale green, it has a splendid pink and white striped headboard from The Headboard Workshop, in fabric by Vanessa Arbuthnot, and combined with a rather delicate antique chair and cabinet, this room is much more girly and feminine, with a lovely Edwardian feel. In such a small space, it’s masterly to have fitted in all these changes of tempo.

The hero moment in here is the claw-foot bath painted the most beautiful pink – Little Greene’s Light Peachblossom. “I got the bath on Gumtree. It was rotting in a garden in Icklesham. I had it re-enamelled by the Bath Doctor in Faversham and then painted the sides and added the brass taps and soap rack.”

That soap rack – both jolly handy and lovely to look at – represents another theme of the whole project. Chic combined with practicality. On the wall next to the bed there is a storage shelf and a built-in rail of hangers and over by the window there’s a flat space next to the mirror (a lovely thing itself, made from a French chateau door) where you could organise your make-up and then put it on in good light. Details so often forgotten in holiday rentals. “My mum and dad travel a lot and my mum said, ‘You must have somewhere with good lighting for make up’…” Something Amy’s visitors must thank her for – as they would for the bedside lights at perfect reading height, with off switches in just the right place for a sleepy hand to find.

No wonder one couple stayed six weeks. But then Amy has undertaken one of the all-important tests that so many people forget to do in rentals and even in their own guest bedrooms. She spent a night in The Outbuilding herself before making it available. “I spent a night out here on my own to check if it was all OK and it was lovely,” she says.

Now, I have to say that is something I would very much like to put to the test myself.