Permitted Development

These are the rules governing the size of any additions you can make to your property without going through Planning Process. They were modified significantly in 2008 and are currently undergoing further amendments; albeit that the latter has not yet been adopted.

Permitted Development Rights are NOT SUBJECTIVE; you either have them or you don’t!

We will establish your Permitted Development Rights, in certain cases there are restrictions on properties Permitted Development Rights, for example with listed properties or homes situated within Designated Conservation Areas or Areas of Outstanding Natural Beauty.

We can explore your Permitted Development Rights, and in the vast majority of cases our clients are surprised by just how much freedom they actually have.

What can I do within Permitted Development?

Home Improvements

  • Build a porch.
  • Carry out internal alterations.
  • Convert and occupy the loft space.
  • Install microgeneration equipment such as solar panels (apart from wind turbines).
  • Install satellite dishes.
  • Erect antenna.
  • Put in rooflights or dormer windows.
  • Put in new doors or windows.
  • Extend the back of your home.

All subject to design constraints; e.g. porch has to be less than 3m³, rooflights and dormers must not face the highway, etc.


  • You can construct all sorts of outbuildings for the use and enjoyment of the home so long as they do not cover more than 50% of the garden space. In Scotland this is reduced to 30%.
  • In Wales and Northern Ireland any outbuildings closer to the house than 5m count as extensions. In Scotland any outbuildings larger than 4m2 and closer to the dwelling than 5m count as extensions.
  • Outbuildings must be single storey with a maximum ridge height of 4m for a pitched roof or 3m for any other kind of roof. The eaves height must be no more than 2.5 metres.
  • If the outbuilding is closer to the boundary than 2m it shall be no higher than 2.5m.

No outbuilding can be forward of the original dwelling. In Wales and Northern Ireland the same applies unless the resulting building would be more than 20m from the road.


  • You can extend a dwelling by 4m to the rear if it’s single storey or 3m if it’s double.
  • There are height restrictions but they boil down to a single storey extension not being higher than 4m in height to the ridge and the eaves, and ridge property.
  • Two storey extensions must not be closer than 7m to the rear boundary.
  • It must be built in the same or similar material to the existing dwelling.
  • Extensions must not go forward of the building line of the original dwelling.
  • Side extensions must be single storey, maximum height of 4m and a width no more than half of the original building.
  • In Designated Areas side extensions require planning permission and all rear extensions must be single storey.
  • An extension must not result in more than half the garden being covered.
  • You can only do it once and the original building is either as it was on 1st July 1948 or when it was built. In Northern Ireland it is as it was built or as it was on 1st October 1973.
  • In Wales and Northern Ireland an extension must not be bigger than 15% of the volume of the existing house or 70m³, whichever is the greater up to a maximum of 115m3. In Designated Areas this volume is reduced to 10% or 50m³, whichever is the greater.
  • In Scotland the limit is 24m² or 20% of the floor area up to a maximum of 30m². In Designated Areas this comes down to 16m² or 10%.

To view ‘The Town and Country Planning (General Permitted Development) Order 1995’ please click here.