If you’re one of the lucky Londoners who enjoys the UK’s fleeting moments of sunshine on your very own roof terrace or a balcony, you might be pleased to know that it can also add an impressive amount to the value of your flat.

According to research by London estate agents Marsh & Parsons, the presence of an outdoor space typically adds 12 per cent to a property’s asking price.

Access to a communal garden commands an 11 per cent premium on average, and as much as 20 per cent in the highly sought-after Little Venice.

Peter Rollings, CEO of Marsh & Parsons, said: “With outdoor space at a premium in the capital, not all properties have their own gardens, so roof terraces, balconies and communal green areas can be just as important to buyers looking to unwind in the open air.

“Vendors have long been aware of how much value traditional home improvements such as a new kitchen or bathroom can add to a property and this research may just persuade them to covert flat roofs or balconies into habitable outdoor oases.”

Currently Marsh & Parsons estimates that just under a third of flats that come on to the market have a balcony, roof terrace or communal garden and says that these properties attract much more interest – and sell faster – than equivalent properties with no outdoor space.

It has also calculated that the average price per square foot of outdoor space in the capital is £897.

Paul Hopkins, managing director of property develop St James (London North), said: “We always aim to include private external space on all our new build developments.

“This is a high priority amongst our buyers, particularly in London, where space comes at such a premium and residents are looking to buy into a lifestyle rather than just a convenient place to live.”

The outside areas at Smithfield Square, St James’ latest development in Hornsey, have been designed to maximise the space on offer.

“Many of the balconies have been intelligently designed to sit in front of a recessed second bedroom, allowing for a deeper square shaped balcony providing a more usable space for outside relaxation,” said Hopkins.

“This also allows maximum light to flood into the living areas whilst still providing direct access from the living room onto the balcony.”

Properties currently for sale in north London with outdoor spaces:

Eldon Grove, Hampstead Village, NW3£4,250,000

Marcus Parfitt

Daleham Mews, Belsize Park, NW3£3,499,950

TK International