Property experts would have us believe that the most expensive homes are selling more easily than those with less noughts on the asking price. Yet nobody would deny that, even at the top end, it's a buyer's market. Agents may have clients with £3million-plus to spend but those buyers want something very special. First on the list of their “must-haves” is an updated version of an informal family room: the so-called super-room.

“Light and space are the key features in this type of room,” says Grant Alexson, of Knight Frank. “There should be a kitchen and dining area at one end and an informal lounging area where the whole family can watch television together at the other. It should, ideally, have a high ceiling, creating a sense of airiness. Another must is big glass doors extending the length of the room leading out into the garden, flooding the room with light.”

However, these buyers still want to have a separate dining room, drawing room and, possibly, a study. “We want to interact with our kids and have this sense of family but at the same time we want to keep a formal side to our lives,” says Sarah Van der Noot, of London Property Search.

Roxburgh House, pictured, a £6million home in Wimbledon built by the developer Diadem Homes, perfectly matches the formula. Its super-room is 42ft by 21ft, its ceiling more than 11ft high and it opens on to landscaped gardens. Nick Jarvis, of Diadem, says: “We only recently became aware of the difference a super-room makes to our sales. We sold two in Cobham, Surrey, to Premier League footballers. Suddenly we were inundated with inquiries.”

The idea of the super-room might have come from wealthy buyers enthused by similar rooms they had seen in the US. However, the architect Charles Barclay thinks that it dates to the 1990s: “Clients were open to new ideas and architects took the opportunity to show off their Modernist influences. Everyone wanted to have the Frank Lloyd Wright look of different living spaces flowing into one another.”

Rigby&Rigby specialises in bespoke home renovations and is prepared to go to great lengths to include a super-room in its projects. For its latest renovation, in Cadogan Street, Chelsea, it took 20 weeks to completely strip out and re-pin the lower-ground floor, then fit it out as a super-room.

The super-room is just as much a showpiece as more formal reception rooms. One super-room in a home in Drayton Gardens, South Kensington, which is being sold by the designer Nicky Murray, includes a state-of-the-art designer kitchen. And a maisonette in Lancaster Gate has a super-room where the owner displays pictures from her own art gallery.

But Charles Barclay warns against thinking that you will automatically improve a home by adding a super-room. “It is quite a design challenge to make this new room a coherent space,” he says. “A badly designed super-room can feel like a vast open garage. Only a well-designed one will enhance your home.”

Contact sheet

Roxburgh House: Robert Holmes & Co , 020-8947 9833, £6 million.

Cadogan Street: Rigby & Rigby , 020-7581 8270, £4.5 million.

Drayton Gardens: Simon Barnes, 020-7499 3434, £4.95 million.

Lancaster Gate: Marsh & Parsons , 020-7313 2890, £2.95 million.

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