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Do I need planning permission for a rear extension in Bristol?
Short answer
A rear extension in Bristol needs planning permission unless permitted development applies. Bristol City Council says those rights apply to houses, not to a flat, a maisonette, or a house above a basement flat. It says a larger single-storey rear extension — between three to six metres on an attached house, or between four to eight metres on a detached house — is only available under permitted development if you do not live in a conservation area, and only if you return its prior notification form. National Class A rules also set a smaller single-storey limit, a height limit, and extra limits in a conservation area, including no rear extension of more than one storey. The Article 4 directions at Sherrin Way and Henbury remove permitted development for alterations and extensions. None of this decides the position for a particular house.
National permitted development rules
The national rules below are taken from the GOV.UK technical guidance for householders in England. That page says it was updated on 10 September 2019. It explains Class A limits for a rear extension. It is not a decision on an individual house.
Class A of Part 1 of Schedule 2 to the Town and Country Planning (General Permitted Development) (England) Order 2015 covers the enlargement, improvement or alteration of a house, including a rear extension. The guidance says these rights do not apply to flats, or to houses created under the change-of-use rights in Classes M, N, P, PA and Q. In this guidance a dwellinghouse does not include a building that contains one or more flats, or a single flat in a building.
Source: Permitted development rights for householders: technical guidance
"Original" means the building as it existed on 1 July 1948 where it was built before that date, and as it was built if it was built after that date. Depth is measured from the base of the rear wall of the original house to the outer edge of the extension wall, not including guttering or barge boards.
Source: Permitted development rights for householders: technical guidance
A single-storey rear extension must not extend beyond the rear of the original house by more than 4 metres if the house is detached, or by more than 3 metres in any other case. In both cases the total height must not be more than 4 metres. The rear wall is the wall directly opposite the front of the house. Extensions within those depths are not subject to the neighbour consultation scheme.
Source: Permitted development rights for householders: technical guidance
Where the house is not on article 2(3) land and not on a site of special scientific interest, a single-storey rear extension must not extend beyond the rear of the original house by more than 8 metres if it is detached, or by more than 6 metres in any other case, and it must not exceed 4 metres in height. Extensions beyond the smaller limit and within those larger limits are subject to a neighbour consultation scheme. Work cannot start until the local planning authority says no prior approval is required, grants prior approval, or 42 days have passed without a decision.
Source: Permitted development rights for householders: technical guidance
Article 2(3) land includes a conservation area, a National Park, the Broads, an area of outstanding natural beauty and a World Heritage Site. On that land, Class A does not permit cladding any part of the exterior with stone, artificial stone, pebble dash, render, timber, plastic or tiles. It also does not permit an extension beyond a side wall, or a rear extension of more than a single storey. The larger 6 metre and 8 metre single-storey allowance does not apply on article 2(3) land.
Source: Permitted development rights for householders: technical guidance
Where the enlarged part has more than one storey, it must not extend beyond the rear wall of the original house by more than 3 metres, and it must not be within 7 metres of a boundary of the curtilage opposite that rear wall. The roof pitch of that enlarged part must, so far as practicable, be the same as the roof pitch of the original house.
Source: Permitted development rights for householders: technical guidance
If any part of the extension is within 2 metres of a boundary of the curtilage, the eaves of the enlarged part must not exceed 3 metres. Extensions and other buildings must not cover more than 50% of the curtilage, excluding the ground area of the original house. Exterior materials, other than those used to build a conservatory, must be of a similar appearance to the existing house. A veranda, balcony or raised platform is not permitted development under Class A. A raised platform is a platform higher than 0.3 metres.
Source: Permitted development rights for householders: technical guidance
Where a new extension will be joined to an existing extension, the size limits apply to the total enlargement: the proposed extension together with the existing one. A local planning authority can remove permitted development rights in an area by an Article 4 direction, and those rights may also have been removed by a condition on a planning permission. Where that has happened, a planning application is needed. Permitted development does not remove the need for building regulations approval or any consent under the Party Wall Act.
Source: Permitted development rights for householders: technical guidance
What Bristol adds
Permitted development in Bristol
Residential permitted development rights only apply to houses. If you live in a flat, maisonette or house above a basement flat, Bristol says it is likely that you will need planning permission for an external extension or alteration.
Source: What is permitted development
Bristol says you can build larger single storey rear extensions under permitted development if you do not live in a conservation area. The size it describes is between three to six metres on an attached house, and between four to eight metres on a detached house. The extension must meet the other permitted development conditions, and you must return the council's householder development prior notification form.
Source: What is permitted development
Bristol says you may still need other consents for that larger single-storey rear extension, for example under building regulations or the Party Wall Acts.
Source: What is permitted development
If you live in certain parts of Bristol, permitted development will not apply, so you will still need to get planning permission.
Source: What is permitted development
Bristol says you will need to meet building regulations even if you do not need planning permission.
If you are still unsure, Bristol says you can apply for a Lawful Development Certificate. The council will decide whether the proposed works need planning permission and send a formal notice.
Bristol says some older houses are protected as listed buildings, and that tighter planning controls apply both to listed buildings and to houses in conservation areas. To check whether a property is listed, the council says to search the National Heritage List for England.
Conservation areas
Bristol designates conservation areas for their special character and appearance, and says they have stricter planning controls than other places.
There are 33 conservation areas in Bristol. The council says they have a special character and appearance, and that it aims to preserve or enhance them.
Source: Conservation areas
Conservation areas have stricter planning controls than other places, so you might need permission before you carry out any type of development.
Source: Conservation areas
Bristol says you can see its conservation areas on the Know Your Place website, or call 0117 922 3000, or email conservation@bristol.gov.uk.
Source: Conservation areas
To find out if a property is in a conservation area, Bristol says to search for it on Planning Online and choose the Constraints tab.
If you are planning any major work in a conservation area, Bristol says you will need a pre-application enquiry so that a planning officer can visit the site and give a formal view.
Article 4 directions
An Article 4 direction removes named permitted development rights in a mapped area. Bristol publishes the list, and the directions do not all cover the same work.
Some areas of Bristol are covered by Article 4 Directions. If your property is in one of these areas, you need planning permission for the works that would normally be covered by permitted development rights.
Source: Restrictions on permitted development (Article 4 Directions)
The Article 4 Direction at Land at Sherrin Way came into force on 26 July 1982. You need planning permission to make alterations and extensions to a dwellinghouse, and for boundary treatments (walls, gates and fences).
Source: Restrictions on permitted development (Article 4 Directions)
The Article 4 Direction at Henbury came into force in 1971. You need planning permission to make alterations and extensions to a dwellinghouse, and for boundary treatments (walls, gates and fences).
Source: Restrictions on permitted development (Article 4 Directions)
The Clifton Village Article 4 Direction came into force in July 1974. You need planning permission for works of alteration that affect the external appearance of the properties in Royal York Crescent, Cornwallis Crescent, Caledonia Place and West Mall.
Source: Restrictions on permitted development (Article 4 Directions)
Bristol has confirmed new Article 4 Directions for parts of Brislington, Frome Vale, Purdown, Southmead and Horfield, St George, and Westbury Park. From 1 January 2027, planning permission is required there for a change of use from a dwelling house (Class C3) to a small house in multiple occupation (Class C4).
Source: Restrictions on permitted development (Article 4 Directions)
Other directions on the same list cover different work. Examples on the page include a change of use between a dwelling house (Class C3) and a small house in multiple occupation (Class C4), and controls on gates, walls, fences, means of enclosure and hard standings.
Source: Restrictions on permitted development (Article 4 Directions)
Design guide
Bristol's design guide for house alterations and extensions is SPD 2, dated October 2005. The council links to it from its supplementary planning documents page.
Supplementary planning documents and other planning guidance · A guide for designing house alterations and extensions (SPD 2)
The points below are rules of thumb in that guide for proposals the council is assessing. They are not the national permitted development limits above.
SPD 2 says that, in assessing proposals for rear extensions, the council will use a 45 degree rule of thumb. An extension should be designed so as not to cross a 45 degree line, on plan and on elevation, projected from the centre of an adjoining neighbour's nearest ground-floor habitable-room window which is perpendicular to the proposed extension.
Source: A guide for designing house alterations and extensions (SPD 2)
The guide says experience has shown that single-storey rear extensions should be designed to a maximum depth of 3.5 metres, but may need to be significantly less in the case of terraced houses.
Source: A guide for designing house alterations and extensions (SPD 2)
The guide says two-storey extensions can be problematic and in any event are unlikely to be acceptable beyond 2.75 metres. On narrow terraced properties it says they are often not possible, because of unreasonable loss of daylight or outlook, or a detrimental sense of enclosure.
Source: A guide for designing house alterations and extensions (SPD 2)
The guide says the council will generally accept extensions that meet those criteria, although it may relax the standards depending on the type or size of property, its location within the city, and the historic context.
Source: A guide for designing house alterations and extensions (SPD 2)
Timescales
Bristol says decisions on a planning application are usually given within eight weeks, or up to 13 weeks for major work. That period includes a statutory 21 day consultation with neighbours and other interested parties.
- Householder planning application
The local planning authority must decide a valid application for householder development within 8 weeks starting with the day after it received the application, unless the applicant and the authority agree a longer period in writing.
Source: Planning appeals: procedural guide (applications on or after 1 April 2026)
- Larger single-storey rear extension
Work cannot start until the local planning authority notifies the householder that no prior approval is required, or gives prior approval, or 42 days have passed without a decision.
Source: Permitted development rights for householders: technical guidance
Checklist
Confirm the property is a house. Bristol says residential permitted development rights only apply to houses, and that a flat, maisonette or house above a basement flat will likely need planning permission for an external extension or alteration.
Source: What is permitted development
Check the conservation area. Bristol says there are 33, that you can see them on Know Your Place, and that you can call 0117 922 3000 or email conservation@bristol.gov.uk.
Source: Conservation areas
Search the address on Planning Online and open the Constraints tab. That is how Bristol says to check whether the property is in a conservation area.
Read the Article 4 list before treating the extension as permitted development. The Sherrin Way direction, in force from 26 July 1982, and the Henbury direction, in force from 1971, both require planning permission for alterations and extensions to a dwellinghouse.
Source: Restrictions on permitted development (Article 4 Directions)
If the house might be listed, search the National Heritage List for England. Bristol says tighter controls apply to listed buildings.
Measure from the rear wall of the original house — the house as it stood on 1 July 1948, or as first built if later — and apply the Class A limits on depth, height, eaves within 2 metres of a boundary, curtilage coverage and materials.
Source: Permitted development rights for householders: technical guidance
Outside a conservation area, a larger single-storey rear extension still needs Bristol's householder development prior notification form, and it must meet the other permitted development conditions.
Source: What is permitted development
Do not start that larger extension until the council says no prior approval is required, grants prior approval, or 42 days pass without a decision.
Source: Permitted development rights for householders: technical guidance
If you apply for planning permission, use SPD 2. Its 45 degree rule is taken from the centre of the adjoining neighbour's nearest ground-floor habitable-room window. The guide gives 3.5 metres for a single storey and 2.75 metres for two storeys as rules of thumb, and says the council may relax them.
Source: A guide for designing house alterations and extensions (SPD 2)
Meet building regulations even if planning permission is not required.
Local questions
Do I need planning permission for a rear extension in Bristol?
Not always. Bristol City Council says residential permitted development rights only apply to houses. A flat, maisonette or house above a basement flat will likely need planning permission for an external extension. A house can still need permission if the extension is outside the national Class A limits, if an Article 4 direction or a condition on an earlier permission has removed the rights, or if it is the larger single-storey scheme and the house is in a conservation area. Bristol says that larger scheme is not permitted development in a conservation area.
How large can a single-storey rear extension be in Bristol?
Under the national guidance, a single-storey rear extension must not go more than 4 metres beyond the rear wall of the original house if it is detached, or 3 metres for any other house, and it must not be more than 4 metres high. Outside article 2(3) land, which includes conservation areas, and outside a site of special scientific interest, those depths can be up to 8 metres for a detached house or 6 metres for any other house, with the neighbour consultation scheme. Bristol describes that larger extension as between three to six metres on an attached house and between four to eight metres on a detached house, and says it applies only if you do not live in a conservation area. You must return the council's prior notification form. These figures are permitted development limits. They are different from the 3.5 metre and 2.75 metre rules of thumb in Bristol's design guide, which the council uses when it assesses a planning application.
What difference does a Bristol conservation area make to a rear extension?
Bristol says there are 33 conservation areas and that they have stricter planning controls than other places. Its permitted development page says you can build a larger single-storey rear extension under permitted development only if you do not live in a conservation area. National guidance treats a conservation area as article 2(3) land. On that land an extension beyond a side wall is not permitted development, a rear extension of more than one storey is not permitted development, and the larger 6 metre and 8 metre allowance does not apply. Cladding the exterior in stone, artificial stone, pebble dash, render, timber, plastic or tiles is also outside Class A there.
Do Bristol's Article 4 directions stop a rear extension?
Not all of them. Bristol says that if your property is in an Article 4 area you need planning permission for the works that direction covers. Two directions require planning permission for alterations and extensions to a dwellinghouse: Land at Sherrin Way, in force from 26 July 1982, and Henbury, in force from 1971. The Clifton Village direction, in force from July 1974, requires permission for external alterations at Royal York Crescent, Cornwallis Crescent, Caledonia Place and West Mall. Other directions on the council's list cover different work, including a change of use to a small house in multiple occupation, or gates, walls, fences and hard standings. New directions for parts of Brislington, Frome Vale, Purdown, Southmead and Horfield, St George, and Westbury Park require permission from 1 January 2027 for a change of use from a dwelling house to a small house in multiple occupation.
How long does a rear extension decision take in Bristol?
Bristol says decisions on a planning application are usually given within eight weeks, or up to 13 weeks for major work, including a statutory 21 day period when neighbours and other interested parties are consulted. GOV.UK says the local planning authority must decide a valid householder application within 8 weeks starting the day after it received the application, unless a longer period is agreed in writing. For a larger single-storey rear extension, GOV.UK says work cannot start until the council says prior approval is not required, grants prior approval, or 42 days pass with no decision.
What does Bristol's design guide say about rear extensions?
The council publishes A guide for designing house alterations and extensions (SPD 2, October 2005) on its supplementary planning documents page. The guide says the council uses a 45 degree rule of thumb, on plan and elevation, from the centre of the nearest ground-floor habitable-room window of an adjoining neighbour. It says single-storey rear extensions should be designed to a maximum depth of 3.5 metres, and may need to be significantly less on a terraced house. It says two-storey extensions are unlikely to be acceptable beyond 2.75 metres. It also says the council may relax those standards depending on the property, its location and the historic context. These are design tests for proposals the council is assessing. They are not the national permitted development limits.
Sources
- What is permitted development
- Guidance on planning permission for householders
- Conservation areas
- Planning permission in conservation areas
- Restrictions on permitted development (Article 4 Directions)
- Supplementary planning documents and other planning guidance
- A guide for designing house alterations and extensions (SPD 2)
- Permitted development rights for householders: technical guidance
- Planning appeals: procedural guide (applications on or after 1 April 2026)