A London house extension goes down one of three routes: permitted development, prior approval for a deeper single storey extension, or a planning application. This page sets out the limits that decide which, the drawings each route needs, and how London boroughs decided householder applications in 2025-26.
(£565 if you supply measured drawings)
Single-storey rear extension
Fixed in writing after a free assessment of your property. Council planning fees are separate.
Every price is the total you pay. Checked 24 October 2026.
The route depends on the storeys, the depth, the side width and the land. The references are to Class A of Part 1, Schedule 2 of the 2015 General Permitted Development Order (GPDO), and every row assumes a house rather than a flat.
| Extension | Limit that decides the route | How it is decided | Where to read more |
|---|---|---|---|
| Single storey rear | No more than 3 m beyond the rear wall of the original house (4 m detached) and no more than 4 m high: A.1(f) | Permitted development. A certificate of lawful development is optional proof | Rear extension drawings |
| Larger single storey rear | Up to 6 m (8 m detached), single storey, no more than 4 m high, and not on article 2(3) land or a site of special scientific interest: A.1(g) and A.4 | Prior approval. The council notifies adjoining owners, who have at least 21 days. If it does not decide within 42 days, work may begin | Single storey extension guide |
| Two storey rear | No more than 3 m beyond the rear wall and at least 7 m from the boundary opposite the rear wall: A.1(h) | Permitted development if every other Class A limit is met. There is no prior approval route | Two storey extension plans |
| Side extension | Single storey, no more than 4 m high and no wider than half the original house: A.1(j) | Permitted development within those limits; a planning application outside them | Side return extension plans |
| Wraparound (side and rear) | Both the rear limits and the side limits apply to the one extension (MHCLG guidance, 'Rear and side extensions'), and the total enlargement is tested: A.1(ja) | Usually a planning application, because the combined width tends to pass half the original house | Wraparound extension plans |
| Anything outside the limits | A householder planning application | Eight weeks from receipt of a valid application, unless a longer period is agreed in writing (DMPO article 34(2)) | Planning application drawings |
| Flat or maisonette | Part 1 rights apply to a dwellinghouse, and the order excludes a building containing flats and a flat within one: GPDO article 2(1). A householder application is for a dwellinghouse (DMPO article 2(1)) | A full planning application, not a householder one | Permitted development rights explained |
| House on article 2(3) land, which includes conservation areas | No side extension, no cladding in stone, render, timber or similar, and no extension of more than one storey beyond the rear wall: A.2. No 6 m or 8 m route | A single storey rear extension within 3 m (4 m detached) can stay permitted development; the rest needs an application | Conservation areas and Article 4 |
Sources: GPDO 2015, Schedule 2, Part 1, Class A, article 2 and DMPO 2015, article 34, read 15 October 2026. An Article 4 direction or a planning condition can remove rights that the order grants, so check the council's list for your street.
Every Class A limit is measured from the original dwellinghouse, which means the house as it stood on 1 July 1948 or as first built if later. An extension added after 1 July 1948, or after the house was built if later, counts against you. The order's total enlargement test, paragraph A.1(ja), adds the proposed work to any existing enlargement it will join and checks the sum against the limits in A.1(e) to (j).
This example is arithmetic, not a real job. Take a semi-detached house with a 2.4 m back addition built by a previous owner and no planning record of it. The owner wants to add a further 1 m at the back. The depth is now 3.4 m beyond the original rear wall, which is above the 3 m permitted development limit for a semi-detached house. The same extension up to 6 m could go through prior approval, if the house is not on article 2(3) land and is otherwise within Class A.
The MHCLG technical guidance makes the same point with a first floor: if a detached house has a single storey extension of more than 3 m that was not part of the original house, adding a storey above it needs an application, because the total enlargement would have more than one storey and project more than 3 m. A measured survey that finds the original walls settles these questions before drawings are drawn.
Paragraph A.4 of Class A sets the procedure for a single storey rear extension that goes beyond 3 m (4 m detached) and up to 6 m (8 m detached).
A written description with the depth, maximum height and eaves height, a plan showing the site and the proposal, the addresses of adjoining premises, your contact details and the fee. The council can refuse if the information is too thin to judge the limits.
The notice must allow at least 21 days for representations, and public holidays are left out when counting those days.
If any adjoining owner or occupier objects, the council decides whether it needs to give prior approval for the impact on the amenity of adjoining premises, and it must consider all adjoining premises, not only the ones that objected.
Work must not begin until the council says prior approval is not required, gives it, or 42 days pass from receipt of the information without a decision. The council can grant it with conditions linked to amenity impact.
The sheets are the same family for every route. What changes is the sheet that carries the risk and the document the council tests it against.
| Route | Core set | Sheet that carries the risk | Council tests it against |
|---|---|---|---|
| Permitted development, with or without a certificate | Location plan, block plan, existing and proposed floor plans and elevations | Elevations and a section marking the original rear wall and the 3 m or 4 m dimension | Class A limits. A certificate application needs a plan to an identified scale with a north point and evidence to verify it (DMPO article 39(2)) |
| Prior approval, larger home extension | A.4(2) description, a site plan showing the extension and any existing enlargement, and the adjoining addresses; floor plans and elevations help the officer | Site plan with the 6 m or 8 m dimension and the neighbours' boundaries | Class A limits, then neighbour amenity if anyone objects |
| Householder planning application | Location plan, block plan, existing and proposed plans, elevations and sections, plus anything on the council's local list | Section to the neighbour's window and the roof form | The local plan, the council's residential design guidance and any conservation area appraisal |
| Building regulations after consent | Constructional plans, sections and details, with structural calculations | Foundation, steel and insulation details | Approved Documents A, B, C, F and L, among others. See building regulations drawings |
Sources: GPDO Class A, A.4(2); DMPO article 39(2); Planning Portal plans and drawings guidance, read 14 and 15 October 2026. Local lists differ: see our planning application drawings page for the borough checklists.
London councils approved 85.6% of 24,758 householder decisions in 2025-26, against 90.3% across England, and the borough range ran from 68.0% to 98.6%.
| Borough | Householder decisions 2025-26 | Approved |
|---|---|---|
| Hammersmith and Fulham | 560 | 98.6% |
| Bexley | 939 | 95.3% |
| Southwark | 612 | 94.8% |
| Kensington and Chelsea | 574 | 94.3% |
| Islington | 389 | 92.8% |
| Sutton | 635 | 92.8% |
| Wandsworth | 970 | 92.3% |
| Merton | 769 | 92.2% |
| Tower Hamlets | 203 | 92.1% |
| Haringey | 702 | 90.9% |
| Lewisham | 637 | 90.4% |
| Hillingdon | 1,184 | 90.2% |
| Camden | 404 | 88.4% |
| Ealing | 993 | 87.7% |
| Croydon | 805 | 87.3% |
| Newham | 395 | 86.8% |
| Brent | 924 | 85.5% |
| Hackney | 421 | 84.3% |
| Enfield | 999 | 83.1% |
| Havering | 1,019 | 82.8% |
| Harrow | 894 | 82.7% |
| Barnet | 1,439 | 82.2% |
| Kingston upon Thames | 766 | 82.0% |
| Richmond upon Thames | 1,362 | 81.7% |
| Redbridge | 1,050 | 81.5% |
| Lambeth | 610 | 81.3% |
| Westminster | 418 | 81.3% |
| Waltham Forest | 789 | 79.3% |
| Bromley | 1,538 | 79.0% |
| Greenwich | 647 | 77.6% |
| Hounslow | 704 | 74.7% |
| Barking and Dagenham | 406 | 68.0% |
Source: MHCLG planning application statistics PS1 and PS2, 2025 Q2 to 2026 Q1 (financial year 2025-26), (other) householder developments, derived in scripts/aggregate/ps1_ps2.py. The City of London recorded one decision and is omitted. Householder decisions include every kind of householder development, not extensions alone. A later MHCLG release (24 September 2026) exists and was not re-pulled.
London's 33 councils refused 1,141 of 4,784 large householder extension prior approval decisions in 2025-26, or 23.9%, and the borough rate ran from 8.3% to 48.1%.
| Borough | Prior approval decisions | Refused | Share refused |
|---|---|---|---|
| Greenwich | 158 | 76 | 48.1% |
| Kingston upon Thames | 77 | 35 | 45.5% |
| Lewisham | 103 | 46 | 44.7% |
| Barnet | 282 | 103 | 36.5% |
| Lambeth | 50 | 18 | 36.0% |
| Waltham Forest | 264 | 87 | 33.0% |
| Brent | 243 | 79 | 32.5% |
| Merton | 254 | 80 | 31.5% |
| Richmond upon Thames | 108 | 30 | 27.8% |
| Hounslow | 213 | 59 | 27.7% |
| Ealing | 269 | 70 | 26.0% |
| Sutton | 139 | 35 | 25.2% |
| Harrow | 438 | 108 | 24.7% |
| Newham | 102 | 23 | 22.5% |
| Haringey | 91 | 19 | 20.9% |
| Wandsworth | 58 | 12 | 20.7% |
| Croydon | 172 | 34 | 19.8% |
| Redbridge | 521 | 93 | 17.9% |
| Barking and Dagenham | 287 | 36 | 12.5% |
| Bromley | 125 | 15 | 12.0% |
| Havering | 228 | 27 | 11.8% |
| Enfield | 280 | 27 | 9.6% |
| Hillingdon | 151 | 13 | 8.6% |
| Bexley | 96 | 8 | 8.3% |
Source: MHCLG PS1, large householder extension prior approval outcomes (not required, granted, refused), 2025 Q2 to 2026 Q1, held in content/data/borough-planning-stats.json. Only boroughs with at least 50 decisions are listed; Camden, Hackney, Hammersmith and Fulham, Islington, Southwark and Tower Hamlets recorded fewer, and Kensington and Chelsea, Westminster and the City of London reported none. The split between 'not required' and 'granted' is recorded differently by different councils and is not compared. A refusal rate says nothing about why each was refused.
These are common errors that move an extension from the cheaper route to the slower one.
Planning permission, permitted development and prior approval decide whether the extension may be built. They do not approve how it is built. Foundations, steelwork, insulation, drainage and ventilation must comply with the building regulations whichever planning route you take, and the building control decision on a full plans application is due within five weeks, or a longer period agreed in writing (regulation 14A(6)). Our building regulations drawings page lists the set.
The Party Wall etc. Act 1996 is a separate regime. Section 1 covers a new wall built on the line of junction, with notice at least one month before work starts. Section 2 covers work to an existing party wall, such as cutting in a steel, and a party structure notice must be served at least two months before the work begins (section 3). Section 6 covers excavation within 3 m of a neighbouring building that goes deeper than its foundations, and within 6 m on the 45 degree test, with notice at least one month before. Each regime is decided separately.
The price panel on this page shows the starting price for a single storey rear extension, a side return, a two storey extension and a wraparound, and what each covers. Every figure is the total you pay, survey included, and the council's planning fee is separate and paid to the council. Our pricing page lists the building regulations and structural options.
Tell us about your project and get a fixed, no-obligation quote back within one working day. If you don't need planning permission at all, we'll tell you that too — for free.
We test the depth, the height, the original rear wall and the boundary distances on paper before the drawings go in, so the route is chosen on the measurements rather than assumed.
Not necessarily. A single storey rear extension within 3 m (4 m on a detached house) and 4 m high can be permitted development, and up to 6 m (8 m detached) it needs prior approval rather than permission. Two storey extensions beyond the 3 m and 7 m limits, side extensions wider than half the original house, flats and anything else beyond the Class A limits need a planning application. An Article 4 direction can remove rights, so check your street first.
Permitted development within the basic limits needs no application. Prior approval is a notification route for a single storey rear extension of 3 m to 6 m (4 m to 8 m detached). The council notifies neighbours, and if any object it assesses amenity impact. If the council has not notified its decision within 42 days of receiving the information, the work may begin, provided the extension is within the Class A limits.
A householder application needs a location plan, a block plan and existing and proposed floor plans and elevations at stated metric scales, usually with a section, plus anything on your council's local list. A prior approval notification needs a written description, a plan showing the proposal and the adjoining addresses. Building regulations need a separate constructional set.
The council has eight weeks from receipt of a valid application to decide a non-major application, unless you agree a longer period in writing (DMPO article 34(2)). An application missing something the council's published list requires may not be valid, which delays the start. Prior approval has a 42-day notification period and a certificate has eight weeks.
Possibly, if it goes no more than 3 m beyond the rear wall, stays at least 7 m from the boundary opposite the rear wall, and meets the height, eaves and materials limits. There is no prior approval route for two storeys, and in a conservation area the extension needs an application. Our two storey extension plans page sets out the limits.
Usually, because the rear limits and the side limits both apply to the one extension, and a combined side and rear extension typically passes half the width of the original house. A wraparound that stays inside both sets of limits would be permitted development, but it is the exception on a London terrace. Our wraparound page explains the tests.
On article 2(3) land, which includes conservation areas, paragraph A.2 removes permitted development for side extensions, for cladding in stone, render, timber or similar, and for extensions of more than one storey beyond the rear wall. A single storey rear extension within 3 m (4 m detached) can still be permitted development, but the 6 m and 8 m route is not available.
It is optional. A certificate under section 192 of the 1990 Act is the council's written confirmation that the proposal is lawful, and a buyer's solicitor may ask for it on a sale. The council has eight weeks from a valid application to decide. It tests the dimensions you submit, so the drawings carry the application.
Sometimes. The Party Wall etc. Act 1996 applies where you build a wall on the boundary, cut into or raise a shared wall, or excavate close to a neighbouring building below its foundations. Notice periods are one month or two months depending on the section. It is separate from planning permission and building regulations.
The price panel on this page gives the starting price for a single storey rear extension, a side return, a two storey extension and a wraparound. Each figure is the total you pay, includes the measured survey and comes with free revisions until the council decides. Council planning fees are paid to the council and are not included. The pricing page lists building regulations and structural options.
Local drawings tuned to each council's design guidance, with live borough approval rates. Pick your area:
House extension plans in Ealing — single and double-storey drawings submitted for you and revised free until your council approves.
View Ealing →House extension plans in Wandsworth — single and double-storey drawings submitted for you and revised free until your council approves.
View Wandsworth →House extension plans in Bromley — single and double-storey drawings submitted for you and revised free until your council approves.
View Bromley →House extension plans in Barnet — single and double-storey drawings submitted for you and revised free until your council approves.
View Barnet →House extension plans in Harrow — single and double-storey drawings submitted for you and revised free until your council approves.
View Harrow →House extension plans in Sutton — single and double-storey drawings submitted for you and revised free until your council approves.
View Sutton →House extension plans in Richmond upon Thames — single and double-storey drawings submitted for you and revised free until your council approves.
View Richmond upon Thames →House extension plans in Kingston upon Thames — single and double-storey drawings submitted for you and revised free until your council approves.
View Kingston upon Thames →House extension plans in Camden — single and double-storey drawings submitted for you and revised free until your council approves.
View Camden →House extension plans in Islington — single and double-storey drawings submitted for you and revised free until your council approves.
View Islington →House extension plans in Haringey — single and double-storey drawings submitted for you and revised free until your council approves.
View Haringey →House extension plans in Enfield — single and double-storey drawings submitted for you and revised free until your council approves.
View Enfield →House extension plans in Waltham Forest — single and double-storey drawings submitted for you and revised free until your council approves.
View Waltham Forest →House extension plans in Hillingdon — single and double-storey drawings submitted for you and revised free until your council approves.
View Hillingdon →House extension plans in Hounslow — single and double-storey drawings submitted for you and revised free until your council approves.
View Hounslow →House extension plans in Brent — single and double-storey drawings submitted for you and revised free until your council approves.
View Brent →House extension plans in Hammersmith and Fulham — single and double-storey drawings submitted for you and revised free until your council approves.
View Hammersmith and Fulham →House extension plans in Kensington and Chelsea — single and double-storey drawings submitted for you and revised free until your council approves.
View Kensington and Chelsea →House extension plans in Westminster — single and double-storey drawings submitted for you and revised free until your council approves.
View Westminster →House extension plans in Merton — single and double-storey drawings submitted for you and revised free until your council approves.
View Merton →House extension plans in Lambeth — single and double-storey drawings submitted for you and revised free until your council approves.
View Lambeth →House extension plans in Croydon — single and double-storey drawings submitted for you and revised free until your council approves.
View Croydon →House extension plans in Hackney — single and double-storey drawings submitted for you and revised free until your council approves.
View Hackney →House extension plans in Tower Hamlets — single and double-storey drawings submitted for you and revised free until your council approves.
View Tower Hamlets →House extension plans in Newham — single and double-storey drawings submitted for you and revised free until your council approves.
View Newham →House extension plans in Redbridge — single and double-storey drawings submitted for you and revised free until your council approves.
View Redbridge →House extension plans in Barking and Dagenham — single and double-storey drawings submitted for you and revised free until your council approves.
View Barking and Dagenham →House extension plans in Havering — single and double-storey drawings submitted for you and revised free until your council approves.
View Havering →House extension plans in Greenwich — single and double-storey drawings submitted for you and revised free until your council approves.
View Greenwich →House extension plans in Lewisham — single and double-storey drawings submitted for you and revised free until your council approves.
View Lewisham →House extension plans in Bexley — single and double-storey drawings submitted for you and revised free until your council approves.
View Bexley →House extension plans in Southwark — single and double-storey drawings submitted for you and revised free until your council approves.
View Southwark →Answer five quick questions and get a free planning score for your exact address — instantly. Then, if you want the full picture, unlock the detailed analysis: your council's live approval rates, local precedents, constraints on your street and a step-by-step route to permission.