Get a lift all year round
With a bit of lateral thinking, you can add outside space to the most unlikely of homes. A flat roof can be turned into a lush and secluded roof garden or a dull facade transformed with the addition of period balconies cascading with flowers.

Where?
Any flat roof can double as an ornamental roof garden with a few window boxes and a bit of trellis. If you want to use the space for sitting out or entertaining, ensure it is strong enough to take the extra weight. A surveyor can advise you. Before investing any money in your nascent terrace, do make sure that you actually own it: check the deeds to the property and, in a flat, the lease, which could contain clauses thwarting your ambitions. You might be able to negotiate rights to or ownership of adjoining space, but get a lawyer involved to formalise the arrangement. Colonising the area around a roof hatch is all very well, but not if it turns into a legal nightmare. It is also worth checking planning permission status with your local authority – even small changes can fall foul of their rules. In a conservation area or with a listed building, you’ll need to check with the council conservation department that you can go ahead. Garage roofs are often options for enhancement, as are fire escapes and extension roofs.

Expanding your horizons
Don’t rule out a surface simply on the grounds of inaccessibility: a spiral staircase up to a flat roof, or a new set of French doors onto a forgotten corner might transform your property. London-based Urbanroofgardens advises on the feasibility of developing your space, bringing together a team of architects, designers, engineers and contractors. The company specialises in roofs and promises to ‘rattle the established cages’ when it comes to roof gardens. Its average commission costs between £7,000 and £35,000.

Floor surfaces
Decking is an easy, cheap option at £30 to £50 per sq m, and will give a grotty asphalt roof an instant facelift – just make sure the surface is strong enough to bear the weight. A thin layer of gravel or pea shingle is a sleek budget option. Light-coloured stone can make the area look bigger. Terracotta or stone tiles are more expensive at up to £60 per sq m plus laying costs, but will turn the space into a grown-up outside room likely to add value to your property if done professionally. Slate or pale limestone are good options – consult a surveyor for advice on the load-bearing capacity of the roof and ensure drainage is adequate. There is now an entire market in ‘exterior design’ – the Society of Garden Designers can help you locate a specialist, or turn to an architect. Grass is the ultimate trendy aerial surface, but totally impractical for the average homeowner. Astroturf can look witty in a city.

Safe perimeters
Solid balustrades or railings are the only safe options for fencing in a roof garden: flimsy trellis is more dangerous than an open drop, as it looks deceptively strong. Structural glass panels are a good modern option for a contemporary look: acid-etched or sandblasted glass lets through but gives privacy. Metal panels look funky, but make sure they’re going to weather well. A small brick wall is another option.

Anything else?
Water damage to the area below your roof garden can be a serious problem. Ensure that the area is well drained, and that plant pots don’t generate areas where damp might seep into the building structure. If neighbours feel you are overlooking their space, crossing their boundaries or obstructing their light with your new area, they can complain to the council. Lighting will allow you to make the most of your new area. Strings of outdoor fairy lights look pretty and an external socket is a good idea – an electrician can give you a quote. An outdoor tap is helpful for watering plants. If you’re making new areas of your property accessible with stairs or doors, don’t forget the security implications.