Roof gardens, once a common sight in London, are enjoying a renaissance, together with the growing popularity of living green roofs. Mayor Ken Livingstone's Living Roofs campaign aims to encourage Londoners to make green roofs, roof gardens and terraces as popular as in other major European cities.
New construction techniques allow for different types of living roofs," says Mayor Livingstone, who adds that, along with small-scale gardens, it is possible to install more ambitious greenery on large buildings "from meadows and other wildlife habitats to allotments, formal gardens and even golf courses".
Among the latest buildings to get a green top is the New Providence Wharf residential scheme in Docklands, where there is a variety of planting, from high-level swathes of sedum with wildflowers to more formal and traditional gardens. Nearby is the Barclays Bank tower at Canary Wharf, which, at 525ft, is thought to be one of the highest rooftop gardens in the world. On a smaller scale, a new housing scheme at Paddington Walk in west London, with landscaping by Gillespies, has exquisitely detailed gardens with distinct Japanese, Indonesian and Moroccan themes.
'We thought a green roof would be a lot more interesting to look out on'
Roof gardens are not new to London. They were popular in the 1930s, epitomised by glamorous schemes, such as the roof gardens at Berkeley Court in Marylebone, which remain a selling point of this grand mansion block.
Most amazing is the one-and-a-half-acre urban oasis of Kensington Roof Gardens, complete with pink flamingos and full-sized trees, Tudor garden, Spanish garden and an English woodland garden. On a smaller scale, the latest green wave includes home-owners who want to do their bit for the environment. In Highbury, Pia Conti incorporated a green roof of low-growing grasses and flowers on her garden extension.
"I didn't know much about green roofs but we thought it would replace the grass we were covering with the extension and be a lot more interesting to look out on than an ordinary tiled roof," says Conti. "The completed project is just great, the roof changes with the seasons and is particularly beautiful in the summer, when it is covered with yellow flowers."
© Mark York
The Highbury extension was designed by architect and green-roof evangelist Dominic Cullinan of Scabal. "A living roof is a great amenity and contributes to bio-diversity by attracting birds and insects," he says. "They can be fitted to existing roofs or incorporated into new structures." He says they can be surprisingly lightweight and don't necessarily need a huge amount of extra structural support.
Cullinan worked on the project with Steve Vincent of specialist company BBS Green Roofing. The benefits of a green roof are manifold. "It enhances the thermal and sound-absorbing performance of the roof, will soak up and retain storm water to help flood management, and reduces dust and smog levels," explains Vincent.
"Because it is a protective layer, a green roof will also increase the roof's life expectancy. And, as if all that isn't enough, this extra planting increases natural habitat for birds, insects and plants, and looks great."
For anyone thinking of installing a green roof, Vincent says the process is easy. He suggests consulting a structural engineer to ensure the proposed roof is strong enough to bear the extra weight and says that, in most cases, planning permission is not required. Costs vary widely according to the structure and access but, as a general guide, he says that for a typical 20sq m roof prices start at £100 a square metre for the green roof system, including water and rot-proof membrane, with labour at an extra £500. Maintenance for most domestic green roofs involves a check-up once or twice a year.
Terraces add value
Whether it is a pretty rooftop terrace or a humble balcony, outside space adds value to any property. "The ideal minimum space should be big enough to invite a few friends round for a barbecue," says Paul Driscoll of central London estate agent Hurford Salvi Carr. "Views are important, and so is a bit of privacy. For buyers who have had outside space before, some sort of terrace is a necessity."
When it comes to calculating the added value of this extra space, figures are difficult to pin down. "It really does vary according to location and the property," says Driscoll.
© Ian McIlgorm
However, in recent research carried out by Hurford Salvi Carr, experts calculated that a balcony can add £12,500 to an apartment, but where there is a fantastic view the uplift can be as much as £20,000. Meanwhile, a terrace of about 20ft by 10ft can add £50,000, and a large terrace of 1,000sq ft or more can add upwards of £100,000.
The research also revealed that these outdoor areas, especially in new-build projects, have become highly sophisticated, with independent power supply and lighting, plumbing for a hot tub and watering plants, a sound system, decking and electrical or gas connections for barbecues.
The latest "must-have" addition to larger terraces is a conservatory or gazebo.
* BBS Green Roofing: 07831 770394; www.green-roofing.co.uk.
* Scabal: 020 7033 8788; www.scabal.net.
* Visit www.livingroofs.org, an independent website with information about all types of green roofing.
* Government body Natural England www.naturalengland.org.uk has information on green roofs and biodiversity.