Here is an exhaustive list of Permitted Development (PD) Rules for single and double storey rear extensions, side and roof extensions, loft conversions, porches and outbuildings. You can use it to check if your project design is within Permitted Development Rights – that is; exempt from requiring Planning Permission.

Permitted Development Brief Potted History

Permitted Development Rules


In 1948, an Act of Parliament became effective which included the introduction of Permitted Development and Planning Permission. It was central to the future of Town and Country Planning, with the introduction of listed buildings. It reduced the number of planning authorities from 1,400 to 145 and gave them a lot of control, whilst requiring them to prepare development policies.
PD Rights state that you can extend your property to a certain degree, without the need for full permission, as long as you follow the relevant PD Rules. These Rights were reviewed in 2008, when certain conventional rules were replaced with more complex regulations regarding extensions and outbuildings. Later, because of the shortage of housing stock, the rules were relaxed for a time to encourage development of existing properties. This reprieve began in 2012 and ends in May 2016.
Permitted Development Important Change on May 2016


Under the more relaxed PD Rights, some families have enjoyed up to 75% extra extension space without needing any Planning Permission.  They have been able to add twice the usual space allowed for single storey rear extensions.
Time is running out because shortly the Government’s relaxed attitude about PD Rules will be renewed. It seems that the more ambient rules regarding domestic extensions will continue until 2019, but there will be additional rules and restrictions to observe. Other PD Rights for offices will also end in May 2016.
The amount of work you can do with your PD Rights varies according to several considerations such as location and how much other development has taken place since1948.




Here are some examples of permitted projects:
Add a rear or side extension
Alter your interior
Using your loft
Add sky lights or a dormer window
Renew your windows and doors
Let’s have a front porch
Solar panels seem a good idea


If your extension doesn’t need full planning permission, then it is a Permitted Development, as long as certain constraints are observed:
Cladding of the outside of a home using stone, pebble, render, timber, tiles or plastic is not a PD on designated land (areas of outstanding natural beauty).
Extensions should not exceed 50% of the land around the existing property. Remember to include sheds etc in your calculation of this limit.
If the planned extension is proud of the front or side elevation and facing a road, then it will not be a PD.
Side extensions are not permitted on designated land.
The choice of materials for exterior development should match the existing house, although this is not necessary with a conservatory.
A side extension must not be wider than half the house width.
Your side extensions can be one storey, up to four metres high.
PD Rules allow a maximum eaves height of three metres if the extension is close to the plot boundary (within two metres).
Your single-storey rear extension can extend back from the existing property by up to3 metres, for a terraced house – or 4 metres for a detached house. If it is not designated land or a site of Special Scientific Interest, you can go up to 6 or 8 metres for terraced and detached houses respectively(until 30th May, 2016.) However the neighbour consultation scheme applies to these increases.
PD Rules allow a maximum height of 4 metres for single storey rear extensions.
The ridge and eaves height for an extension cannot be higher than the original property.


Extensions above one storey will not be permitted on designated land.
Extensions should not exceed 50% of the land around the existing property. Remember to include sheds etc in your calculation of this limit.
The ridge and eaves height for an extension cannot be higher than the original property. PD Rules allow a maximum eaves height of three metres if the extension is close to the plot boundary (within two metres).
If your rear extension is above one storey, PD Rules cannot allow it to reach further than 3 metres. Neither must it come within 7 metres of the boundary facing the rear of the house.
In extensions above one storey, PD Rules state that the roof pitch must match the roof pitch on the existing property, as far as is practically feasible.
Materials for the development’s exterior should be similar to those used on the original property.
Obscure-glaze your upper wall window or roof slope light if on your side elevation. It must also not open unless above 1.7 metres from the floor of its respective room.
PD Rules do not allow balconies or verandas.


Your loft conversion is considered a Permitted Development than does not require planning permission, as long as a few rules are observed.
On designated land, loft conversions will not be a Permitted Development
To be a Permitted Development any additional roof space created must not exceed these volume allowances:
If an additional roof space exceeds the following allowances, it will not be a Permitted Development:
40m3 on terraced houses.
50m3 on detached or semi-detached houses.
(Please note that previous roof additions will have to be figured into this volume calculation, even if the work was carried out by a former owner.)
Permitted Developments do not include extending proud of the existing roof slope plane on the front elevation if it faces a road.
Use materials which appear similar to the existing property.
Your extension cannot be higher than the highest point on the existing roof.
Permitted Developments do not include balconies, verandas or raised platforms.
A side window should be obscured and not able to be opened, unless the opening mechanism is situated at least1.7m above its respective room floor.
Roof extensions should be set back, as far as reasonably feasible by at least 20cm from the eaves, unless it is a hip or gable roof. Measure the 20cm along the plane of the roof. The roof extension should not hang over the wall of the house.
Your roof or loft project might have an impact on any existing bats. For this kind of work you should think about protected species. You may need a survey and possibly a licence.


When you measure the area (on the ground) of your porch externally, it should not be above 3m3
Your porch height should not be above 3m.
Your porch cannot come within 2m of the boundary if it faces a road.


If the property is on designated land, an outbuilding at the side will not a Permitted Development.
If it is a listed building, an outbuilding will not be permitted.
If the property is in a national park, the Broads, or Areas of Outstanding natural Beauty and World Heritage Sites, the area of an outbuilding above 20m from any of the house walls should not be above 10m2 in order to be a Permitted Development.
Outbuildings beyond the front elevation of the house are not allowed.
Outbuildings should not take up more than 50% of the area of land around the original house. Remember to include all sheds, existing outbuildings & existing extensions to the original house in this calculation for a new outbuilding.
A new outbuilding should not be residential, self-contained living accommodation. A microwave antenna is not permitted.
Your new outbuildings should be single storey only, to a maximum (eaves) height of 2.5m. Overall the total height should not exceed 4m – on dual pitched roofs – and 3m on other roof-types.
If your new outbuilding comes within 2m of the boundary, then the whole building should not be higher than 2.5m.
PD Rules do not allow balconies. You can have a raised platform like decking, but make sure it does not exceed 30cm high.
If you have a container with oil to heat your home, it should be smaller than 3,500 litres capacity volume, to come under Permitted Development. Please note all the other PD conditions above apply to containers too.



Designated Land covers Areas of Outstanding Natural Beauty, national parks, B roads, Conservation Areas and World Heritage Sites.
Original House refers to how the house stood as at 1 July 1948 (unless it was built after that date, in which case it would refer to its new condition – that is: unaltered). Someone else may have extended your property before you


Although PD Rules look like hard work to read, it is a good pain because you may not need to do a full planning application. You could run your own proposal whilst learning about PD Rules yourself. If this seems a bit overwhelming or risky, we have a range of services to enable your progress with ease.
As you peruse and refer back to this guide, please kindly note that local authorities do have powers which can remove PD Rights from homes, especially in conservation areas. Planning permission might not be required due to your Permitted Development Rights, however we do recommend that you obtain a Certificate of Lawful Development which will reassure you that your proposal does not in fact require permission and that your use of the building is legal.
To apply for your Certificate of Lawful Development, remember to include supportive documents such as drawings & calculations. This is also something we can help with.
Easily learn which PD rules affect you with our free consultation, covering design, fees and planning advice

Contact us for more information

Phone : (020) 80044464