Applications, appeals, permitted development, enforcement and planning strategy across England
Planning explanations, updates and practical guidance in video form
Wraparound extension: outrigger and half-width rules
A wraparound extension joins space beside a house or its rear outrigger to space behind it. It is a popular design, but many full-width versions fail England’s Class A permitted development rules.
The common mistake is to call the whole scheme a rear extension and check only the 3 m, 4 m, 6 m or 8 m rear allowance. If it projects beyond an original side wall, the half-width rule applies too.
Need help with permitted development?
Permitted development can avoid a full planning application, but only if the right applies and every relevant limit and condition is met. Planning Geek can check the planning history, Article 4 directions and other restrictions, and help with a lawful development certificate or prior approval where needed.
What is an outrigger?
An outrigger is a part of a house projecting at the rear, often a narrower back addition containing the kitchen on a Victorian or Edwardian house. The exact name is less important than its age and the direction of its walls.
We first establish whether it belongs to the original house: the house on 1st July 1948, or as first built if later. An original outrigger supplies original walls from which some Class A tests are made. A later addition is an existing enlargement, and cannot simply provide a fresh set of allowances.
The side wall can be inside the main house’s width
The long wall of an original outrigger can form a side elevation. There is no rule that a side elevation must be the outermost side of the main rectangular part of the house.
That means an infill alongside the outrigger can be beyond an original side wall while also being behind an original rear wall. Both sets of restrictions can apply. Whether the work is in the back garden, or can be seen from the road, does not decide this side-width test.
In this example the original house is 8 m wide. A 2 m wide infill projecting 3 m behind the main original rear wall meets the illustrated half-width and ordinary rear-depth tests. It remains subject to all the other Class A limits and conditions. In particular, such a side enlargement is excluded on article 2(3) land.
Measure the whole enlargement, not just the side strip
A.1(j) limits an enlargement beyond an original side-elevation wall to a single storey, no more than 4 m in height and a width no greater than half the original house. Government guidance measures the original house at its widest point.
If a single connected proposal wraps around the outrigger and reaches across the back, do not split that proposal into a narrow side strip and an unrelated rear box. The width of the enlargement as a whole matters.
Here the original house is 8 m wide, giving a 4 m half-width limit. The connected wraparound enlargement is 8 m across. It fails the side-width test even though the projection is 3 m behind the outrigger and 6 m behind the main rear wall.
Those rear measurements do not make the scheme permitted development. A larger home extension application cannot waive a failure of the side-width limit.
There may be several original rear walls
The original main rear wall and the end wall of an original outrigger can both be rear walls. Identify every relevant original rear wall that the proposal extends beyond and test the applicable projection. Satisfying the measurement from the furthest rear wall does not necessarily satisfy the measurement from another original wall.
Government technical guidance contains examples of stepped houses where an enlargement passes one rear-depth measurement but fails another. A straight line drawn across the end of the outrigger is not a substitute for tracing the actual original walls.
Building the side and rear sections separately
A.1(ja) deals expressly with new work that joins an existing enlargement of the original house. It applies the relevant A.1(e) to (j) limits to the total enlargement, meaning the new work and the existing enlargement it will join.
In the example, an 8 m wide original house already has a 3 m wide side extension. A new rear extension joining it creates an 11 m wide total enlargement. The new joined proposal exceeds the 4 m half-width limit even if the earlier side extension was lawful.
The same issue can arise with later additions to an outrigger. A different construction phase, a different owner or a separate application does not reset the test. Physically separate development may need a different assessment, but a gap should not be treated as an automatic workaround.
Can any wraparound extension qualify?
Yes, the GPDO does not contain a blanket ban on every design described as a wraparound. A limited arrangement can meet all the applicable side and rear tests. But a typical full-width joined scheme frequently exceeds half the original house’s width.
We would check these points in order:
- Establish the original house and distinguish original outriggers from later additions
- Identify the principal, side and rear walls that the proposal extends beyond
- Draw the complete proposed enlargement and any existing enlargement it will join
- Measure its full width and every relevant rear projection
- Check height, eaves, boundaries, ground coverage, protected land, materials and the remaining Class A requirements
Protected land and other restrictions
On article 2(3) land, Class A excludes an enlargement beyond an original side-elevation wall, including beside an original outrigger. A side wall fronting a highway is also restricted by A.1(e). There may additionally be planning conditions or an Article 4 direction removing rights.
Use the main Class A guide for the complete checklist, the side extension guide for width and height, and the rear extension guide for rear projections.
Get certainty before construction
If the proposal is intended to rely on permitted development, an accurately prepared Lawful Development Certificate application can establish whether it would be lawful. Drawings must show the original and existing house and the whole proposal clearly.
A scheme that fails Class A may still obtain planning permission through a householder application. The right response is to choose the correct route, rather than force an unsuitable design into the permitted development limits.
Sources and Class A legislation
Current GPDO Part 1 and article 2 definitions provide the statutory wording. The government householder technical guidance explains measurements and examples, but must be read alongside later legislative amendments.
Read the Class A legislation
Class A – enlargement, improvement or other alteration of a dwellinghouse
Permitted Development
A. The enlargement, improvement or other alteration of a dwellinghouse.
Development not permitted
A.1 Development is not permitted by Class A if—
(a)permission to use the dwellinghouse as a dwellinghouse has been granted only by virtue of Class G, M, MA, N, P , PA or Q of Part 3 of this Schedule (changes of use);
(b)as a result of the works, the total area of ground covered by buildings within the curtilage of the dwellinghouse (other than the original dwellinghouse) would exceed 50% of the total area of the curtilage (excluding the ground area of the original dwellinghouse);
(c)the height of the part of the dwellinghouse enlarged, improved or altered would exceed the height of the highest part of the roof of the existing dwellinghouse;
(d)the height of the eaves of the part of the dwellinghouse enlarged, improved or altered would exceed the height of the eaves of the existing dwellinghouse;
(e)the enlarged part of the dwellinghouse would extend beyond a wall which—
(i)forms the principal elevation of the original dwellinghouse; or
(ii)fronts a highway and forms a side elevation of the original dwellinghouse;
(f)subject to paragraph (g), the enlarged part of the dwellinghouse would have a single storey and—
(i)extend beyond the rear wall of the original dwellinghouse by more than 4 metres in the case of a detached dwellinghouse, or 3 metres in the case of any other dwellinghouse, or
(ii)exceed 4 metres in height;
(g)for a dwellinghouse not on article 2(3) land nor on a site of special scientific interest, the enlarged part of the dwellinghouse would have a single storey and—
(i)extend beyond the rear wall of the original dwellinghouse by more than 8 metres in the case of a detached dwellinghouse, or 6 metres in the case of any other dwellinghouse, or
(ii)exceed 4 metres in height;
(h)the enlarged part of the dwellinghouse would have more than a single storey and—
(i)extend beyond the rear wall of the original dwellinghouse by more than 3 metres, or
(ii)be within 7 metres of any boundary of the curtilage of the dwellinghouse being enlarged which is opposite the rear wall of that dwellinghouse;
(i)the enlarged part of the dwellinghouse would be within 2 metres of the boundary of the curtilage of the dwellinghouse, and the height of the eaves of the enlarged part would exceed 3 metres;
(j)the enlarged part of the dwellinghouse would extend beyond a wall forming a side elevation of the original dwellinghouse, and would—
(i)exceed 4 metres in height,
(ii)have more than a single storey, or
(iii)have a width greater than half the width of the original dwellinghouse;
(ja)any total enlargement (being the enlarged part together with any existing enlargement of the original dwellinghouse to which it will be joined) exceeds or would exceed the limits set out in sub-paragraphs (e) to (j);
(k)it would consist of or include—
(i)the construction or provision of a verandah, balcony or raised platform,
(ii)the installation, alteration or replacement of a microwave antenna,
(iii)the installation, alteration or replacement of a chimney, flue or soil and vent pipe, or
(iv)an alteration to any part of the roof of the dwellinghouse ; or
(l)the dwellinghouse is built under Part 20 of this Schedule (construction of new dwellinghouses).
A.2 In the case of a dwellinghouse on article 2(3) land, development is not permitted by Class A if—
(a)it would consist of or include the cladding of any part of the exterior of the dwellinghouse with stone, artificial stone, pebble dash, render, timber, plastic or tiles;
(b)the enlarged part of the dwellinghouse would extend beyond a wall forming a side elevation of the original dwellinghouse; or
(c)the enlarged part of the dwellinghouse would have more than a single storey and extend beyond the rear wall of the original dwellinghouse;
(d)any total enlargement (being the enlarged part together with any existing enlargement of the original dwellinghouse to which it will be joined) exceeds or would exceed the limits set out in sub-paragraphs (b) and (c).
Conditions
A.3 Development is permitted by Class A subject to the following conditions—
(a)the materials used in any exterior work (other than materials used in the construction of a conservatory) must be of a similar appearance to those used in the construction of the exterior of the existing dwellinghouse;
(b)any upper-floor window located in a wall or roof slope forming a side elevation of the dwellinghouse must be—
(i)obscure-glazed, and
(ii)non-opening unless the parts of the window which can be opened are more than 1.7 metres above the floor of the room in which the window is installed; and
(c)where the enlarged part of the dwellinghouse has more than a single storey, or forms an upper storey on an existing enlargement of the original dwellinghouse, the roof pitch of the enlarged part must, so far as practicable, be the same as the roof pitch of the original dwellinghouse.
A.4—(1) The following conditions apply to development permitted by Class A which exceeds the limits in paragraph A.1(f) but is allowed by paragraph A.1(g).
(2) Before beginning the development the developer must provide the following information to the local planning authority—
(a)a written description of the proposed development including—
(i)how far the enlarged part of the dwellinghouse extends beyond the rear wall of the original dwellinghouse;
(ii)the maximum height of the enlarged part of the dwellinghouse; and
(iii)the height of the eaves of the enlarged part of the dwellinghouse;
(iv)where the enlarged part will be joined to an existing enlargement of the dwellinghouse, the information in sub-paragraphs (i) to (iii) must be provided in respect of the total enlargement (being the enlarged part together with the existing enlargement to which it will be joined);
(b)a plan indicating the site and showing the proposed development and any existing enlargement of the original dwellinghouse to which the enlarged part will be joined;
(c)the addresses of any adjoining premises;
(d)the developer's contact address; and
(e)the developer's email address if the developer is content to receive communications electronically,
together with any fee required to be paid.
(3) The local planning authority may refuse an application where, in the opinion of the authority—
(a)the proposed development does not comply with, or
(b)the developer has provided insufficient information to enable the authority to establish whether the proposed development complies with,
the conditions, limitations or restrictions applicable to development permitted by Class A which exceeds the limits in paragraph A.1(f) but is allowed by paragraph A.1(g).
(4) Sub-paragraphs (5) to (7) and (9) do not apply where a local planning authority refuses an application under sub-paragraph (3) and for the purposes of section 78 (appeals) of the Act such a refusal is to be treated as a refusal of an application for approval.
(5) The local planning authority must notify each adjoining owner or occupier about the proposed development by serving on them a notice which—
(a)describes the development by setting out the information provided to the authority by the developer under paragraph A.4(2)(a);
(b)provides the address of the proposed development;
(c)specifies the date when the information referred to in sub-paragraph (2) was received by the local planning authority and the date when the period referred to in sub-paragraph (10)(c) would expire; and
(d)specifies the date (being not less than 21 days from the date of the notice) by which representations are to be received by the local planning authority.
(6) The local planning authority must send a copy of the notice referred to in sub-paragraph (5) to the developer.
(7) Where any owner or occupier of any adjoining premises objects to the proposed development, the prior approval of the local planning authority is required as to the impact of the proposed development on the amenity of any adjoining premises.
(8) The local planning authority may require the developer to submit such further information regarding the proposed development as the authority may reasonably require in order to determine the application.
(9) The local planning authority must, when considering the impact referred to in sub-paragraph (7)—
(a)take into account any representations made as a result of the notice given under sub-paragraph (5); and
(b)consider the amenity of all adjoining premises, not just adjoining premises which are the subject of representations.
(10) The development must not begin before the occurrence of one of the following—
(a)the receipt by the developer from the local planning authority of a written notice that their prior approval is not required;
(b)the receipt by the developer from the local planning authority of a written notice giving their prior approval; or
(c)the expiry of 42 days following the date on which the information referred to in sub-paragraph (2) was received by the local planning authority without the local planning authority notifying the developer as to whether prior approval is given or refused.
(11) The development must be carried out—
(a)where prior approval is required, in accordance with the details approved by the local planning authority;
(b)where prior approval is not required, or where sub-paragraph (10)(c) applies, in accordance with the information provided under sub-paragraph (2),
unless the local planning authority and the developer agree otherwise in writing.
(12) The local planning authority may grant prior approval unconditionally or subject to conditions reasonably related to the impact of the proposed development on the amenity of any adjoining premises.
(16) When computing the number of days in sub-paragraph (5)(d), any day which is a public holiday must be disregarded.
Explore GPDO Part 1
Choose the work you are planning. These guides explain the English rules for houses.
- Part 1 overview
Start here for permitted development at a house - Class A: house extension and alteration
Rear and side extensions, windows and doors - Class AA: additional storeys
Build upwards above an existing house - Class B: roof enlargement
Dormers and hip-to-gable enlargements - Class C: other roof alteration
Rooflights and other roof alterations - Class D: porch
Porches outside an external door - Class E: outbuilding
Garden buildings, pools and other incidental development - Class F: hard surface
Driveways, paths and patios - Class G: chimney and flue
Chimneys, flues and soil and vent pipes - Class H: satellite dish
Microwave antennas on the house or in its curtilage - Paragraph I: definitions
Terms used in Part 1
Page Created: 25th September 2026