Do I Need Planning Permission?

Converting an existing residential cellar or basement into a living space is unlikely to require planning permission as long as:

  • A separate stand alone unit is not created. For example, you could in theory create a separate granny annexe which would require planning permission.
  • The usage of the basement is not significantly changed. For example, if you wished to run a business activity such as commercial storage from there, then you would require planning permission.
  • A light well is not added.
  • It does not affect the appearance of the property.

If you need to excavate in order to create a new basement, planning permission is required if:

  • It will involve major work.
  • A new separate unit of accommodation is created.
  • It alters the appearance of the external appearance of your home. For example, the addition of a light well.
  • if your home is Listed, you will require Listed Building Consent for internal and external works.

Building Regulations?

If you decide to use your basement to create more usable living space, please be aware that Building Regulations will apply. Building regulations will cover fire escape routes, ceiling height, ventilation, damp proofing, electrical wiring and water supplies.
Underpinning and foundation work may also be needed. See

You must also consider the Party Wall Act 1996 if other properties adjoin yours and you share walls.