Single storey extension is the easy way to add some space to your house. Most ground-floor extensions consist of open-plan kitchen and dining areas connected to the garden through generous amounts of glass. Many properties in London are ideally suited to this kind of expansion. The Victorians left a legacy of fantastic innovations but they also built row upon row of L-shaped houses. The kitchen usually extends out into the garden, leaving a dead space that more often than not has become a dingy patio or a dumping ground for family clobber.

Planning Permission

It is fall under permitted development if following requirements met:

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  • No more than half the area of land around the "original house"* would be covered by additions or other buildings.
  • No extension forward of the principal elevation or side elevation fronting a highway.
  • No extension to be higher than the highest part of the roof.
  • Maximum depth of a single-storey rear extension of 3 metres for an attached house and 4 metres for a detached house.
  • Maximum height of a single storey rear extension of 4 metres.
  • Maximum depth of a rear extension of more than 1 storey of 3 metres including ground floor.
  • Maximum eaves height of an extension within 2 metres of a boundary of 3 metres.
  • Side extensions to be single storey with maximum height of 4 metres and width no more than half that of the original house.
  • Materials to be similar in appearance to existing house.
  • No verandas, balconies or raised platforms.
  • Upper-floor, side facing windows to be obscure glazed; any opening to be 1.7 metres above the floor.
  • On designated land* no permitted development for rear extensions of more than 1 storey.
  • On designated land no cladding of the exterior.
  • On designated land no side extensions.

Cost

The cost of extending your home varies enormously, of course, but generally depends on the floor area and the design specification. Side extensions are the cheapest, starting at about £20,000. But a cutting-edge design — perhaps a glass box kitted out with a top-of-the-range kitchen and connecting to a re-landscaped garden — could set you back more than £130,000. Still, with moving costs often exceeding the £100,000 mark, an extension can make financial sense.