The pop-up buildings that leave a legacy

Carmody Groarke's Filling Station and Frieze pavilions have confirmed its reputation as one of the country's leading architects, says Tim Walker.

At this month's Frieze Art Fair in Regent's Park, the pavilions were almost as striking as the artwork: light-filled timber structures, encompassing not only the now-epic event, but also the park's native trees. For the second year running, they were designed by one of London's most exciting young architecture firms, Carmody Groarke, which has made a virtue of taking on temporary projects and turning them into thrilling, unforgettable buildings.

One of 2012's most talked-about restaurant openings, for example, was Shrimpy's, part of The Filling Station: a ribbed, semi-opaque fibreglass shell, wrapped around the site of a former service station in King's Cross. Instead of looking out onto the grotty main road, as the service station forecourt once did, the 50-cover restaurant – housed in its former kiosk – now looks out over the calm waters of the Regent's Canal.

"Because of the heavy traffic, we needed to close the space," explains Kevin Carmody. "However, the road is on the south side of the site, which is where most of the light into the space comes from. So we needed material that brought the light, but not the view. The fibreglass is used for railway sidings; it's low-cost and robust and we constructed it with rented scaffolding, so it will return to the market sustainably afterwards."

The Filling Station's structure is intended to survive only two years before the site passes to property developers. Though Shrimpy's calls itself a pop-up, its projected lifespan is the same as that of an average new restaurant, and somewhat longer than many of Carmody Groarke's other projects. Studio East Dining, a restaurant on the roof of a then half-finished Westfield Stratford, was made using materials from the construction site, and overlooked the nearby Olympic Park for a mere three weeks in 2010. The Double Club, a nightclub concept in collaboration with the artist Carsten Höller, was split into Western and Congolese-themed spaces; its lifespan, in a warehouse in Islington, was six months.

Carmody Groarke also created the "Blind Light" installation for Antony Gormley's 2007 exhibition of the same name at the Hayward Gallery. Among its other exhibition designs was the acclaimed Bauhaus show at the Barbican earlier this year. A 160-metre long "Skywalk" in Bloomsbury, made for the 2008 London Festival of Architecture, attracted 25,000 visitors during its three-day existence.

Kevin Carmody is 38, his partner Andy Groarke, 40. The recession has forced many aspiring young restaurateurs to prove their worth with pop-ups; similarly, Carmody Groarke has gone after building projects with brief lives, allowing it to create large, high-profile public structures when other architects of similar age are still designing domestic houses in relative obscurity. "They have a professionalism for architects of that age which it normally takes a long time to establish," says Ellis Woodman, executive editor of Building Design. "I can't think of another British practice which is further ahead in its career."

The partners insist their temporary buildings are no less significant to their practice than the permanent ones. Indeed, they resist the term "temporary" altogether. "Calling something 'temporary' is loaded," says Groarke. "When things are being built for a short period of time, they have just as many design questions as things that are there 'forever'. We don't see these as embryonic rehearsals; they're serious building projects in their own right. We're very fortunate to have built a lot of things."

Carmody was born and brought up in Canberra, Australia's capital. Andy Groarke, by contrast, is from the Manchester suburbs. The partners met and became friends as employees of leading London firm David Chipperfield Architects, where Carmody impressed the boss sufficiently to work on designs for Chipperfield's own apartment. The pair were involved in projects together including Gormley's studio in King's Cross, and when they won a competition to create The Parachute Pavilion at Coney Island, New York, they decided to strike out on their own. Their first Carmody Groarke project was an interior on the west coast of Ireland. From a staff of two in 2006, the firm has now grown to 20, in a notably calm office above a music shop on noise-filled Denmark Street.

Its projects are varied, but its work carries a signature. Many of its commissions have been constructed using singular materials: the fibreglass cladding of The Filling Station; engineered timber for the pavilions at Frieze; a single vast block of granite for the tsunami memorial at the Natural History Museum. This entrepreneurial approach to any and every commission is another trademark; at Frieze, for instance, its innovations created 8,000 extra square feet of covered space between the trees of Regent's Park than any previous pavilion designer had achieved – or tried to.

At the end of 2011, Carmody was announced as the winner of a competition to build its most ambitious permanent project to date: the new Windermere Steamboat Museum in the Lake District.

The firm does build houses, too – but not just any houses. It designed a home for the artist Julian Opie, and are presently at work on Gormley's. "These clients are not dissimilar to our other clients," Carmody insists. "They want a place to live. Having said that, there is a sensibility to light and space, and an understanding of language, which helps artists to articulate and to engage with us as clients."