“My name is Maitrivajri,” says the lady waiting at the entrance to a smart black barn, deep in the Suffolk countryside. “It means a diamond thunderbolt of universal loving kindness.”

It’s not quite what you expect to encounter on the edge of the sleepy village of Walsham-le-Willows, but then this is no ordinary barn. Since 2000, Potash farm has been home to Vajrasana, the rural outpost of the London Buddhist Centre, now reborn as a £4m purpose-built retreat complex.

As the loving thunderbolt ushers us into the lofty communal living room, views open out on to a secluded courtyard garden, where a concrete colonnade marches around a hidden oasis of grasses, wildflowers and cherry trees. The sharp white frame gleams in the sun against the black wooden buildings, while a perforated brick screen at one end provides glimpses of the bright white stupa in a further courtyard beyond. Maybe it’s the hot summer afternoon, but the place somehow seems to fuse a sense of more exotic climes with the local world of agricultural sheds. It feels of its place, yet totally other.

“There were no real precedents for this sort of thing,” says architect Cindy Walters, one half of women-led practice Walters and Cohen, purveyors of polite, airy modernism to the likes of Bedales School, the Hurlingham Club and Oxbridge colleges. “It’s not a boutique hotel, but nor is it an ascetic monastery.” She and her team came on a retreat here early in the design process to fully immerse themselves in the routine, and realised that a lot of it simply “revolves around taking your shoes on and off and drinking cups of tea”.

The atmosphere she has crafted for this slow-paced collective domestic life is something like John Pawson meets Muji. It is minimal but not oppressively so, and has a slightly spartan atmosphere without being overly utilitarian. It has the comforting, cloistered air of a Maggie’s Centre, and the inoffensive good taste of one of Alain de Botton’s Living Architecture holiday homes. It is architecture that fades into the background, allowing your mind to concentrate on higher things.

The main buildings are simply built of white-painted blockwork, punctuated by the regular rhythm of precast concrete portal frames, and clad with timber boarding that’s been charred and oiled to give it a dark, smoky patina, echoing nearby barns. The mostly shared bedrooms, which accommodate up to 60 guests – or “retreatants” – are simple affairs, their double-height proportions and relatively compact plan giving an appropriately cell-like quality.

“There’s an element of renouncing,” says Maitrivajri, before pointing out the designer concrete light fittings and big globe lightbulbs, which add a touch of boutique chic to the transcendental experience. She’s particularly proud of the salt and pepper shakers she chose for the communal dining room.

It’s all a big step up from the previous facility, which had been cobbled together by volunteers over the years from a motley collection of pre-existing farm sheds. A former garage served as the men’s dormitory and two solitary huts were built in the corners of the paddock, while a cave-like shrine room was constructed from straw bales stacked up in a circle in the barn and rendered with concrete.

“It was all a bit makeshift and tatty before,” says Abhayavajra, whose name translates as “fearless in the pursuit of ultimate reality”. Ordained in 1995, he has lived on the site since the early 00s and takes care of the day to day running of the place, hosting regular weekend retreats for people coping with stress, addiction, depression – as well as anyone simply looking to find a moment of calm away from the frenetic pace of city life.

Established in a former Victorian fire station building in Bethnal Green in the 1970s, the London Buddhist Centre has since grown to become a thriving community hub, home to a vegetarian restaurant, charity shops and residences, seeing over 1,000 people attend its meditation workshops and yoga classes each week. A partnership with Tower Hamlets council facilitates mindfulness and wellbeing courses for care workers and people suffering from anxiety and addiction, which will extend to the Vajrasana retreat.

The new complex is mostly funded by the sale of a house in Primrose Hill, which was left to the order when a longstanding member of the community died in 2008, along with other donations including a £100,000 bequest from the fashion designer Alexander McQueen.

It has paid for a handsome facility a world away from the former makeshift barns. Beyond the main garden courtyard, around which community life revolves, lies an entire “temple precinct”, where the sparkling stupa – carved in Northern Ireland from Portuguese limestone – stands in a courtyard next to a small water garden, in front of a large shrine room.

The culmination of this processional sequence, the shrine room houses a magnificent gilded Buddha, carved with a startlingly contemporary face and set in a gold-painted apse, while a clerestory of perforated brickwork casts ever-changing pools of dappled light across the floor.

Stepping back out into the secluded cloister, whatever your spiritual leanings, it’s quite hard to pull yourself away.

• Vajrasana retreat centre is at Walsham-le-Willows, Suffolk.