Permitted Development Rights for Householders: 2026 Technical Guide
Householders can carry out a surprising amount of development without planning permission — extensions, loft conversions, outbuildings, even whole new storeys — under the General Permitted Development Order (GPDO) 2015, Schedule 2, Part 1. This is the technical guide to every class, updated for 2026, including the limits that catch people and the certificate that protects you.
Before the classes: five rules that govern everything
These rights belong to dwellinghouses only. Flats and maisonettes have no householder PD rights — and a house converted to flats lost them at conversion. (Use as a small HMO is a separate question — see our London HMO guide.)
Everything is measured from the original house — as first built, or as it stood on 1 July 1948. Previous extensions, including the last owner's, use up the allowance.
Designated land changes the rules. Conservation areas, AONBs, National Parks, the Broads and World Heritage Sites ("article 2(3) land") cut several classes back sharply; listed buildings stricter again.
Article 4 Directions and old planning conditions can remove these rights entirely — both are property-specific and invisible until someone checks.
PD is not a free-for-all on paperwork. Building Regulations always apply, the Party Wall Act often does, and since the Levelling-up and Regeneration Act, unauthorised operational works begun after 25 April 2024 need ten years (not four) before they're immune from enforcement — so "build first, argue later" has never been a worse strategy.
Because of points 2–4, the professional habit is simple: confirm the position with a Lawful Development Certificate (Proposed) before building. Half the application fee, binding, and the document every future buyer's solicitor will ask for.
Class A — Extensions and alterations
The workhorse class: rear and side extensions, new windows and doors, general enlargement.
Single-storey rear extensions
Max 3 m beyond the original rear wall (terraced and semi-detached) or 4 m (detached).
Under the "larger home extension" route these stretch to 6 m / 8 m respectively — but only via the neighbour consultation (prior approval) procedure, and not on article 2(3) land.
Max height 4 m; where the extension comes within 2 m of a boundary, eaves max 3 m.
Side extensions
Single storey only, max height 4 m, and max width half the width of the original house.
Not permitted on article 2(3) land.
Extensions of more than one storey
Max 3 m beyond the original rear wall, and only where the extension is at least 7 m from the rear boundary.
Roof pitch to match the original so far as practicable; upper-floor side-facing windows obscure-glazed and non-opening below 1.7 m.
On article 2(3) land, rear extensions are limited to single storey.
Universal Class A limits
No more than 50% of the curtilage covered by buildings (cumulative, counting outbuildings).
Nothing forward of the principal elevation, and nothing higher than the highest part of the existing roof.
Materials of similar appearance to the existing house (except conservatories).
No verandas, balconies or raised platforms under this class.
On article 2(3) land, exterior cladding is not PD.
Class AA — Additional storeys (the one most guides still miss)
Since 2020, Class AA permits upward extension of a house: up to two additional storeys on a house of two or more storeys, or one on a single-storey house — subject to a prior approval application covering external appearance, amenity impacts and more. Headline limits: the house must have been built between 1 July 1948 and 28 October 2018; the extended house can't exceed 18 m total height; new storeys go on the principal part of the house only; no PD on article 2(3) land or for houses converted to other uses. It is the most condition-laden right in Part 1 — genuinely a prior-approval project rather than a "just build it" right — but on the right house it adds a floor without a full application.
Class B — Roof additions (dormers and loft conversions)
Additional roof space capped at 40 m³ (terraced) or 50 m³ (semi/detached) — cumulative since the house was built.
No extension beyond the roof plane of the principal elevation fronting a highway; nothing higher than the existing ridge.
Dormers set back, so far as practicable, at least 0.2 m from the original eaves; materials of similar appearance.
Side-facing windows obscure-glazed and non-opening below 1.7 m; no balconies or raised platforms.
Not permitted on article 2(3) land — conservation-area lofts need an application.
Class C — Other roof alterations
Rooflights and re-roofing: max projection 0.15 m from the roof plane, nothing higher than the ridge, side-facing rooflights obscure-glazed/non-opening below 1.7 m.
Class D — Porches
Max 3 m² footprint (externally measured), max 3 m high, and at least 2 m from any boundary fronting a highway.
Class E — Outbuildings
Garden rooms, offices, gyms, pools and stores — for purposes incidental to enjoying the house:
Single storey; max eaves 2.5 m; max overall height 4 m (dual-pitched roof), 3 m otherwise — or 2.5 m total within 2 m of any boundary.
Nothing forward of the principal elevation; the 50% curtilage cap applies cumulatively.
No verandas/balconies; containers max 3,500 litres; not within the curtilage of a listed building.
On article 2(3) land: no outbuildings at the side, and a 10 m² cap on buildings more than 20 m from the house in National Parks/AONB/WHS contexts.
The trap: an outbuilding used as a separate dwelling is never PD — that's a planning application and, frequently, an enforcement case.
Class F — Hard surfaces
Driveways and hardstanding: where a new front-garden surface exceeds 5 m², it must be porous, or run-off must drain to a permeable area within the curtilage.
Class G — Chimneys and flues
Max 1 m above the highest part of the roof; on article 2(3) land, not on a wall or roof slope fronting a highway on the principal or side elevation.
Class H — Satellite dishes and antennas
Max two antennas; size limits by location (1 m general, 0.6 m on chimneys, 35-litre cubic cap); nothing above the ridge (or chimney rules where applicable); on article 2(3) land, not on elevations visible from a highway. Antennas must be sited to minimise visual impact and removed when redundant.
The practical sequence
Check the property, not the class — original-house history, conservation status, Article 4s, stripped rights, flats.
Design inside the limits — and where the scheme wants more, compare the PD scheme against a planning application (in Enfield, for instance, the application route runs on its own precise rules).
Certificate it — LDC (Proposed) before works; LDC (Existing) to regularise historic works.
Run Building Regulations and party wall in parallel — PD exempts you from planning, nothing else.
Bashkal handles all of it — PD assessments, certificates, prior approval applications for larger extensions and additional storeys, and the planning applications where PD won't stretch. If you're planning works to your home anywhere in London, contact us before you build.
Verified 5 June 2026 against the GPDO 2015 (as amended), Schedule 2, Part 1, and MHCLG's Permitted Development Rights for Householders: Technical Guidance. Rights vary by property and change over time — confirm the position for your specific house before relying on this guide. Further reading: MHCLG technical guidance.
