Permitted development rules for extensions, loft conversions, porches and outbuildings

This guide provides a detailed list of Permitted Development Rules for single-storey extensions, two-storey rear extensions, loft conversions, roof extensions, porches and outbuildings. Use these lists as a reference tool to check if your project plans are within the planning permission exempt Permitted Development Rights.  

This article will be useful to anyone wanting to understand permitted development rules throughout England. If you are in Cambridge, St Albans or anywhere in East Anglia and London areas then we are local architects who can provide specific hands on help with permitted development rules. You can contact us here.

The history of Permitted Development rules

The concept of Permitted Development was introduced alongside the need for planning permission in the Town and Country Planning Act of 1948. Permitted Development Rights mean that you can extend your home up to a certain amount without full planning permission, so long as you follow the many Permitted Development rules. In 2008 Permitted Development rights were reviewed. Some old conventions were replaced and more complex rules for extensions and outbuildings added in. Then, in an an attempt to stimulate growth, Permitted Development rules were 'relaxed' for a three year period 2012. This period is coming to an end in May 2016.

Relaxed Permitted Development rules are due to change on 30 May 2016!

Under Permitted Development Rights some people have been able to benefit from up to 75% more space being added to the home without the need for Planning Permission. Right now it is possible to achieve double the normal allowance to ground floor rear extensions. 

But there are only a few more months before the Governments relaxed approach to Permitted Development rules are set to change. At this stage it looks like the relaxations for domestic extensions will continue until 2019 although there will be more rules and restrictions to adhere to. Office to residential Permitted Development Rights will not be extended past May 2016.

The level of work you can undertake within your Permitted Development rights depends on a variety of factors including your location and the extent of work you have already carried out post 1948. 

 

 

get help understanding your permitted development rights

 

Types of projects covered within Permitted Development rules

Subject to constraints some of the permissible projects are:

  • Extending the back of your home
  • Carrying out internal alterations
  • Loft conversions that enable you to convert and occupy the loft space
  • Putting in roof lights or dormer windows
  • Putting in new doors or windows
  • adding a front porch
  • Installing micro-generation equipment such as solar panels
 

Permitted Development rules for a single-storey extension

An extension or addition to your house is considered to be a Permitted Development not requiring a full application for planning permission, provided the following limits and conditions are met.

  1. On designated land*, cladding of any part of the exterior of a dwelling (and extensions) with stone, artificial stone, pebble dash, render, timber, plastic or tiles is NOT Permitted Development. 
  2. Extensions (including previous extensions) and other buildings must not exceed 50% of the total area of land around the original house*. Sheds and other outbuildings must be included when calculating the above 50% limit.
  3. Extensions forward of the principal elevation or side elevation of a house and fronting a highway are NOT Permitted Development.
  4. On designated land* side extensions are NOT Permitted Development.
  5. Materials used in exterior work are to be similar in appearance to those of the exterior of the existing house. This condition does not apply when the extension is a conservatory.
  6. The width of the side extension must not have a width greater than half the width of the original house*.
  7. Side extensions are to be single storey with a maximum height of four meters.
  8. If the extension is within two meters of a boundary, maximum eaves height should be no higher than three meters to be a Permitted Development.
  9. Single-storey rear extensions must not extend beyond the rear of the original house* by more than 3 meters, if an attached house or by 4 meters if a detached house. In addition, outside designated land* and sites of Special Scientific Interest the limit is increased to 6 meters if an attached house, or 8 meters, if a detached house until 30 May 2016. These increased limits (between 3 meters and 6 meters and between 4 meters and 8 meters respectively) are subject to the neighbour consultation scheme.
  10. Single storey rear extensions must not exceed a height of 4 meters.
  11. The maximum eaves and ridge height of extension must be no higher than the existing house.
 

 

get help with permitted development rules for your SINGLE-storey extension

 

PERMITTED DEVELOPMENT RULES FOR A two-STOREY rear EXTENSION

  1. On designated land* extensions of more than one storey are not a Permitted Development. 
  2. Extensions (including previous extensions) and other buildings must not exceed 50% of the total area of land around the original house*. Sheds and other outbuildings must be included when calculating the above 50% limit.
  3. Maximum eaves and ridge height of the extension must be no higher than the existing house. If the extension is within two meters of a boundary the maximum eaves height should be no higher than three meters to be a Permitted Development.
  4. 4. Extensions of more than one storey must not extend beyond the rear wall of the original house* by more than three meters or be within seven meters of any boundary opposite the rear wall of the house.
  5. The roof pitch of extensions higher than one storey are to match that of the existing house, as far as is practicable.
  6. Materials used in the exterior work are to be similar in appearance to those of the exterior of the existing house.
  7. Any upper-floor window in a wall or roof slope in a side elevation must be obscure-glazed and non-opening unless the parts which can be opened are more than 1.7 meters above the floor of the room in which it is installed.
  8. No balconies or verandas are a Permitted Development.
 

 

GET HELP WITH PERMITTED DEVELOPMENT RULES FOR your two-STOREY rear EXTENSIONS

 

PERMITTED DEVELOPMENT RULES FOR A loft conversion or roof extension

A loft conversion for your house is considered to be a Permitted Development, not requiring an
application for planning permission, provided certain limits and conditions are met.
 

  1. Loft conversions are NOT a Permitted Development for houses on designated land*
  2. To be a Permitted Development any additional roof space created must not exceed these volume allowances:
    1. 40 cubic metres for terraced houses.
    2. 50 cubic metres for detached and semi-detached houses.
      Bear in mind that any previous roof space additions must be included within this volume allowance. Although you may not have created additional space a previous owner may have done so. 
  3. An extension beyond the plane of the existing roof slope of the principal elevation that fronts a highway is NOT a Permitted Development.
  4. Materials are to be similar in appearance to the existing house.
  5. No part of the extension is to be higher than the highest part of the existing roof.
  6. Verandas, balconies or raised platforms are NOT a Permitted Development.
  7. Any side-facing windows must be obscure-glazed and non-opening unless the parts which can be opened are more than 1.7 metres above the floor of the room in which it is installed.
  8. Roof extensions, apart from hip to gable ones are to be set back, as far as is practicable, at least 20cms from the eaves. The 20cm distance is measured along the roof plane. The roof enlargement cannot overhang the outer face of the wall of the original house*.
  9. Work on a loft or a roof may affect bats. You need to consider protected species when planning work of this type. A survey may be needed, and if bats are using the building, a licence may be required.
 

 

GET HELP WITH PERMITTED DEVELOPMENT RULES FOR your loft conversion

 

PERMITTED DEVELOPMENT RULES FOR the erection of a porch

  1. The ground area of the porch, measured externally, is not to exceed three square meters.
  2. The highest part of the porch is not to exceed three meters.
  3. No part of the porch is to be within two meters of any boundary that fronts a highway.
 

PERMITTED DEVELOPMENT RULES FOR outbuildings

1. On designated land* outbuildings to the side of the house are not a Permitted Development.
2. Outbuildings are not permitted within the grounds of a listed building
3. In national parks, the Broads, Areas of Outstanding natural Beauty and World Heritage Sites the total area to be covered by any outbuilding more than 20 meters from ANY WALL of the house must not exceed 10 square meters to be a Permitted Development.
4. Outbuildings are not permitted forward of the principle elevation of the original house*.
5. Outbuildings and other buildings must not exceed 50% of the total area of land around the original house*. Sheds and all other outbuildings and extensions to the original house* must be included when calculating this 50% limit.
6. To be a Permitted Development, any new building must not itself be separate, self-contained, living accommodation and must have no microwave antenna.
7. Outbuildings must be single storey with a maximum eaves height of 2.5 meters and a maximum overall height of 4m with a dual pitched roof, or 3 meters in any other case.
8. If the outbuilding is within 2meters of the property boundary the whole building should not exceed 2.5 meters in height.
9.Balconies are not a Permitted Development. Raised platforms such as decking are a Permitted Development provided they are no higher than 300mm
10. Containers such as those used for domestic heating purposes, must not exceed 3,500 litres capacity to be a Permitted Development. The other Permitted Development conditions which apply to outbuildings listed above also apply to containers.

 

 

GET HELP WITH PERMITTED DEVELOPMENT RULES FOR your outbuildings

 

Definitions used in Permitted Development Rules

  • *Designated land includes national parks, B roads, areas defined as Outstanding Natural Beauty, conservation areas and World Heritage Sites.
  • *Original house means the house as it was first built or as it stood on 1 July 1948 (if it was built before that date). Although you may not have built an extension to the house, a previous owner may have done so. 
 

Conclusions about permitted development rules

Although Permitted Development Rules might appear long, arduous and complex, they can mean that a full planning application is not required. It is possible to manage your own project and get to grips with Permitted Development Rules through your own research. If you feel that this is not your area of expertise and not a risk worth taking then we can help you progress your project with confidence. 

Although you can use this reference to your hearts content, we do need to issue a word of warning. Permitted Development Rights can also be removed from properties by local authorities. For example, this could happen if your property is in a conservation area. Although planning permission may not be needed due to your Permitted Development Rights, we always recommend that you apply for a Certificate of Lawful Development. This certificate will give you the reassurance that the plans you have for your property really do not require planning permission and that the existing use of your building is lawful.  A Certificate of Lawful Development application will need to be supported by suitable drawings and calculations and we can help you with this application.


understand the permitted development rules that affect you with OUR kickstart consultation. QUICKLY GET TO GRIPS WITH DESIGN, COSTS AND PLANNING. we mainly work with clients in cambridge, st albans and throughout east anglia and london. 

Like this post? Consider sharing it or saving it for later.