THIS IS A QUESTION WE CONSTANTLY HEAR. The answer in most cases is NO.  As it’s not always as straight forward as that we have created a guide to help you finding out how you can use your Permitted Development Rights (PDR’s).planning permission

Do I need planning permission for my garden room?/
Planning permission is not required providing use of the building is “incidental to the enjoyment of the main dwelling house” and its design falls within the definition of “permitted development”. Permitted development essentially allows home owners to construct an outbuilding in their back garden, covering up to 50% of the original garden, providing it is:​

  • Less than four metres in height with a pitched roof
  • Less than three metres high with a flat roof
  • No taller than 2.5 metres; if closer than two metres to the boundary.
  • Not in the grounds of a listed building
  • In national parks, the Broads, Areas of Outstanding Natural Beauty and World Heritage Sites the total area to be covered by all outbuildings more than 20 metres from ANY WALL of the house must not exceed 10 sqm.


The permitted building cannot be used as an “independent separate dwelling” but members or dependents and guests of the main household can stay there, but it cannot be let out or sold as a separate dwelling.

Planning authorities vary in their approach to annexes and some will try to resist the development even where it constitutes permitted development. In this instance, it can be easier to construct the outbuilding for some other use, such as a home office, and then change the use once the work is complete.

planning permission

Normally Building Regulations don’t apply if the building is under 30sqm but if its over 15sqm and closer than 1 meter to a boundary you would have to comply with the fire regulation and make the wall/walls fire retardant ie with non-combustible materials. We fire proof those walls. If in doubt, always check with your local planning authority. Whether or not planning permission is required, the building will need to comply with the Building Regulations.

If a planning application is required, it will take 8-10 weeks for a decision, following registration. If the property is an annexe, the planners will usually place a condition on its use to prevent letting out to a third party.  A planning application for a garden outbuilding currently costs £172 in England. Building Regulations consent will cost from £200-£300 upwards, depending on scale.

Permitted development work can commence without notice, unless Building Regulations or a Party Wall agreement is required because the building work is on or near the boundary with the neighbours.

For further information on the Permitted Development Rights for outbuildings please visit: Planning Portal