Raise the roof – Lowri Turner’s Home Improvements

Need more outdoor space in your life? A lofty terrace needn’t have sky-high costs

It’s an increasingly precious commodity. Green space – a place to unwind, de-stress and escape the traffic – once meant buying a house with a garden, but with property prices pushing more and more people into flats, we’re having to get creative. As Amir Schlezinger, of My Landscapes, says: ‘The way people live in London now, they are increasingly living on the roof,’

Half of Schiezinger’s garden design business is now in the sky. His typical client is aged between 25 and 45 and doesn’t have children, but just wants somewhere to sip a cool glass of wine in the evening.

Even those who do have children are now going for roof terraces. ‘You need your own space even more if you have kids,’ says Schlezinger. Safety is an issue if you have small children and Schlezinger warns never to leave a child on a terrace. There is also a legal minimum height for handrails around a terrace of 43 inches from finished floor level.

Child-friendliness should also govern your choice of floor covering. Ceramic ‘promenade’ tiles can be slippery when wet and are cold on bare feet. Decking is great for kids as it is warm and non-slip.

One product well worth a look is Dalsouple – a rubber tile that cups together and is available in a huge range of colours, including silver and black.

You can construe! a roof terrace literally on the roof if you have a flat area, or on top of an extension. Either way, your first issue is access. Rooftop terraces can usually be created by putting in stairs or a ladder and a skylight. Terraces on the top of extensions, most commonly ground-floor kitchen extensions, often mean converting a window.
However, as squeezing great aunt Maud through a sash window is not really that practical, it is better to remove the window and install French doors instead.

You will need to knock out the ‘apron’ – the brickwork below the existing window – and widen the opening to about 3ft 6in.

Then you need to add support in the form of a reinforced concrete lintel above the new doors. This should cost about £1,500 in total. A cheaper option is to leave the window width as it is and put in a single door.

Remember, if you live in a conservation area or your building is listed, you will need to submit a planning application. You will need to do this even if your home is modern, if your new terrace overlooks anyone, or if
there is the possibility it might compromise neighbours’ light.
Once you have access, you have to build your terrace. Your first job is to strengthen the floor. The existing roof must be removed, new joists laid and a parapet constructed. A minimum of two courses of brick should be laid around the edge to support balustrades and a handrail or glass panels. Then you put the new roof on.

According to Nick London, of N. London Construction, asphalt is ‘old hat’. He favours a three-layer felt system that comes on a roll and is cut to fit.

At this point slapping decking or tiles straight down is a no-no. ‘If you put slabs on to felt or asphalt the water will run through the joints and lie stagnant against the felt. This will make it rot,’ says London- First you must create a floating floor. Joists made from a minimum of 6in x 2in timber that has been treated so it won’t rot should be bolted to a frame. This can then be fixed to the top of the courses of bricks at the edges.

You need a 6in gap between the roof and the bottom of the joists so air can circulate and water can run off. The reason you bolt this frame to the wall is to prevent water running into the room below should the surface be pierced. If you are using decking, this can sit on top of the new joists. For tiles, you will need to lay a treated wood floor, then tile on top.

London quotes a price of at least £5,000 for building a terrace, including installing the French doors, but this can go a lot higher.

Urban Roof Gardens (0800 652 8848, www.urbanroofgardens.com), which specialises in chic roof gardens, says you should allow £10,000 to £25,000 from the first sketch to planting the last bamboo.

Charlie and Sarah Mole constructed a roof terrace at their four-bedroom flat in Hammersmith (to let through Foxtons at £775 per week. With a garden of only lift, the couple felt they needed more outside space and the resulting new terrace measures 23ft x 12ft.

The couple wanted a design that was low-maintenance and the result was architectural spiky leaves and gently wafting bamboo. The floor surface, which is mainly pebble but with a timber boardwalk, gives the terrace a definite whiff of the seaside.

Urban Roof Gardens (0800 652 8848, www.urbanroofgardens.com)