How to create your own roof terrace

Ned Browne 30 November -0001

Depending on what research you believe, properties with outside space are worth 10-25 per cent more than their garden-less equivalents. If you own a top-floor flat, adding a roof terrace could enrich you and revolutionise your life.

Getting started

roof terrace

Much depends on your property. If you have easy access to a flat roof, that’s a great starting point—it’s fairly straightforward to add an external door. 

Other properties may have London roofs or attic spaces whose ridgeline is too low for a loft conversion. Installing a roof terrace on these properties will be more complex, not least because you’ll need a new staircase. Apart from knowing the cost of a new roof, there are several other considerations that you need to make.

Whatever the current configuration, you’ll almost certainly need planning permission. The process is no different from any other planning application. To maximise your chance of success, make sure you show the plans for your terrace to your neighbours. 

Common complaints include: being overlooked, an altered skyline, a loss of privacy, smells from al fresco dining and noise. Reassure them that you’ll be the model neighbour. 

In addition, you should check for precedent—if there are other terraces on your street or nearby, make sure that’s mentioned in your application.

Read more: How to build a community with your neighbours


Other considerations

roof terrace
Image via Women and Wanderlust

You’ll need to employ a structural engineer. Their job is to ensure the supporting walls and floor timbers can carry the additional weight. When making that calculation, they’ll need to consider the weight of floor covering, pot plants and the maximum possible number of people likely to be on the terrace at a given time. 

It’s almost certain you’ll have to replace the floor joists. On larger terraces, you may need steel beams too.

Safety is a key concern—the sky garden has to be safe for children too. As a rule of thumb, any railing has to be 1100mm high with no gaps more than 99mm wide. But always check with Building Control before ordering the handrail.

Water drainage should be planned well in advance. Most roof terrace will be built on a slight pitch and drain to one corner. Check for existing downpipes you may be able to connect to.

Read more: How to create a patio garden


Finish touches

roof terrace
Image via Brilliant Lighting

Lighting and outside sockets are essential. And, if possible, create some storage too. The more you have to cart up and down, the less likely you are to use your new outside room.

Consider the surrounding area as this might influence your choice of flooring, wall covering and railing. But don’t be afraid to be bold—funky roof terraces definitely add that wow factor. Paint one wall a vivid colour; get some stripy deckchairs; string up some Tibetan prayer flags.


How much does it cost?

If you have easy access to a flat roof and know a good builder, it could be as cheap as £10,000. The main things you would need to pay for include:

  • Plans and the planning application
  • Building control
  • A builder/structural engineer
  • A new external door
  • Electrics
  • Reinforcing the floor joists
  • Decking (or an alternative floor covering)
  • The handrail
  • New drainage

If you’re removing a pitched roof and installing a new staircase, the costs could rise to £25,000 or more, depending on the size of the terrace.


Perfectly formed

roof terrace
Image via House to Home

For many busy city dwellers, roof terraces are perfect. They get the benefit of outside space without the hassle of mowing the lawn. 

What’s more, hopefully, you’ll see more sunrises and more sunsets.


Read more from Ned Browne

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