Key Points for Side Extensions

Any side extension you propose can be no wider than half the width of the original dwelling house. In this case, the original house means as it was first built or as it stood on 1st July 1948. If you intend to build within 2 m of the boundary, height restrictions apply depending on the style of extension you propose.

You can build upon no more than 50% of your garden area

Remember to include those outbuildings which already exist here in your calculation (say your garage or shed for example).

If you live within any area that enjoys a statutory designation* such as a conservation area or national park, do remember that it will not be possible to build a side extension without planning permission. See the planning application section on information on how to apply for planning permission.

Do I need Planning Permission?

Planning Permission will not be required if:

  • The extension to the side of the property is only single storey and no higher than 4 m and no wider than half the width of the original dwelling house.
  • Conservatories and single storey rear extensions within 2 m of a boundary are no higher than 3 m with a flat roof or 4 m with a pitched roof.
  • Materials must match the existing.
  • No more than 50% of your private garden area can be built upon. In this calculation, you must include any outbuildings that already exist here.