You do not need planning permission if:

  • You do not build it forward of the front elevation of the house;
  • It is less than 3m high with a flat roof and 4m high for a pitched roof;
  • Any part of it that is 2m away or closer is less than 2.5m high;
  • The proposal doesn’t involve the need to construct a raised platform more than 300mm high;
  • It will take up no more than 50% of the garden area.

Other restrictions may well apply if for example you live in a Conservation Area or your house is Listed so it is worth checking with the relevant Local Authority.