Permitted Development Rights in London 2026: What You Can Build Without Planning Permission

Permitted Development Rights are a national framework set by the Town and Country Planning (General Permitted Development) (England) Order 2015 (the GPDO 2015), as amended. They grant automatic planning permission for certain categories of development, provided specified limits and conditions are met.

For residential properties (dwellinghouses — not flats, not HMOs, not commercial), the relevant permitted development rights for home improvements fall under Part 1 of Schedule 2 to the GPDO 2015:

• •**Class A** — Enlargement, improvement or other alteration to a dwellinghouse (including extensions)
• •**Class B** — Roof alterations (including loft dormers)
• •**Class C** — Other roof alterations (including rooflights/Velux windows)
• •**Class D** — Porches
• •**Class E** — Buildings, enclosures, swimming pools, containers (outbuildings)
• •**Class F.1** — Hardstanding
• •**Class G** — Chimneys, flues, combustion appliances

**Key point: PD rights apply to dwellinghouses only.** Flats, maisonettes (even in converted houses), houses in multiple occupation (HMOs), and any property that has been converted from commercial use may have limited or no PD rights for the works covered by Part 1. If you live in a flat, you always need planning permission for external alterations.

• **PD rights can be removed or restricted by:**
• •An Article 4 Direction (widespread in London Conservation Areas and some residential areas)
• •Conditions attached to the original planning permission for the property or estate
• •The property being listed (listed buildings always require listed building consent for alterations)
• •A legal agreement (Section 106 agreement) attached to a previous permission

Always check whether Article 4 applies to your property before proceeding. The council's planning portal or a Prior Approval / Certificate of Lawfulness check will confirm.

**Class A** — Extensions to dwellinghouses

The following limits apply for a single-storey rear extension:

• **Detached houses:**
• •Maximum extension depth: 8 metres from the original rear wall
• •Maximum height: 4 metres at the eaves; 3 metres at the eaves if within 2m of a boundary
• •Larger Home Extension Scheme: extensions over 4m and up to 8m deep require prior approval (neighbour consultation scheme) — you must notify the council and wait 42 days. Not all councils process this quickly.

• **Semi-detached and terraced houses:**
• •Maximum extension depth: 6 metres from the original rear wall
• •Maximum height: same as above
• •Larger Home Extension Scheme: extensions over 3m and up to 6m deep require prior approval

• **Two-storey extensions:**
• •Maximum depth: 3 metres from the original rear wall
• •Must be at least 7 metres from the rear boundary
• •Cannot exceed the height of the existing house
• •No permitted development for two-storey side extensions

• **Side extensions:**
• •Only single-storey under PD
• •Maximum width: half the width of the original house
• •Cannot be on the principal elevation (street-facing side)
• •Planning permission required for two-storey side extensions in all cases

• **Important London-specific points:**
• •Many London boroughs have Article 4 Directions that restrict extensions in residential areas. Particularly common in: Lambeth, Southwark, Hammersmith & Fulham, Kensington & Chelsea, and all Conservation Areas across all boroughs.
• •Conservation Areas cover large portions of inner London. If your property is in one, even PD-eligible extensions may require planning permission due to Article 4.
• •Wraparound extensions (combining a rear and a side extension) typically require planning permission because the side component exceeds the half-width rule or the combination goes beyond PD limits.

**Overall limits on all extensions:** The total footprint of all extensions (existing and proposed) must not exceed 50% of the total area of land around the original house (the curtilage). If previous extensions have already used up a significant portion of this allowance, the new extension may exceed the limit.

**Class B** — Additions or alterations to a roof

Loft conversions involving dormers can be permitted development under Class B, subject to the following limits:

• **Volume limits:**
• •Detached and semi-detached houses: up to 50 cubic metres of additional roof space
• •Terraced houses: up to 40 cubic metres of additional roof space

Note: these are cumulative limits — they apply to all roof additions (existing and proposed) combined. If a previous dormer or hip-to-gable was done, the remaining allowance is reduced.

• **Position requirements:**
• •The dormer must not project in front of the building's principal elevation (street-facing roof slope)
• •The dormer must not be higher than the highest part of the existing roof
• •Materials used must be similar in appearance to the existing house

**Class C** — Other roof alterations

Rooflight (Velux) windows on any slope (including the front slope) can be permitted development under Class C, provided they do not protrude more than 0.15 metres beyond the plane of the roof.

• **Conditions that remove loft PD rights:**
• •Conservation Area: dormers on the rear slope are usually permitted, but any dormer visible from a public highway (front or side) requires planning permission
• •Article 4 Direction in a Conservation Area: even rear dormers may require planning permission
• •Listed buildings: no PD rights for any roof additions
• •Flats: no PD rights

**Front dormers:** PD rights explicitly exclude dormers on the principal elevation (the front). Front dormers always need planning permission — and are very unlikely to be approved in Conservation Areas.

**Mansard conversions:** Mansard loft conversions (which rebuild the roof to a near-vertical rear slope) are never permitted development and always require planning permission. This is because the change in roof form exceeds the Class B conditions.

**Class E** — Buildings, enclosures, containers, swimming pools, and similar structures within the curtilage

Garden buildings, home offices, studios, sheds, garages (detached), and similar outbuildings can be permitted development under Class E:

• **Conditions:**
• •Must be within the curtilage of the house (your garden or grounds)
• •Must not be in front of the principal elevation
• •Maximum height: 2.5 metres if within 2 metres of a boundary; 4 metres for a dual-pitched roof; 3 metres for any other roof, if more than 2 metres from a boundary
• •Must not cover more than 50% of the total curtilage area (combined with any other outbuildings and the extensions)
• •Must not be used as a separate dwelling unit

• **No PD for outbuildings in:**
• •Conservation Areas if the outbuilding is between the side elevation and the boundary
• •Any listed curtilage

**Habitable room use vs. ancillary use:** An outbuilding can be used as a home office, gym, studio, or similar ancillary use under PD. It cannot be used as a separate self-contained dwelling (bedroom with kitchen and bathroom as a separate unit) without planning permission. The distinction is fine — a garden room with a toilet and a shower for occasional use (not permanent occupation) is generally acceptable under PD; a fully self-contained annex with its own kitchen is not.

• **Lawful Development Certificate (LDC)**:
• Even when work is permitted development, it is strongly advisable to apply for a Lawful Development Certificate. This is not a planning application — it is a confirmation from the council that the proposed works are lawful. Benefits:
• •Provides legal certainty (useful when selling the property)
• •Protects against enforcement action if a neighbour complains
• •Confirms PD applies before you start work

Cost: £103 for proposed works; £234 for works already done. Turnaround: typically 4–8 weeks.

**Prior Approval (Larger Home Extension Scheme)**: For extensions over 4m (detached) or 3m (semi/terrace) but within the maximum PD limits (8m or 6m), prior approval is required from the council. The council notifies your immediate neighbours and allows them 21 days to object. If objections are received, the council assesses whether the impact on amenity is acceptable. If no objections, or if the council finds no unacceptable impact, prior approval is granted.

Timeline: 42 days from the council's acknowledgement date. The council must decide within 42 days or the approval is deemed granted.

• **Common mistakes homeowners make:**
• •Assuming a Conservation Area still has PD rights (often it does not, due to Article 4)
• •Not checking whether previous owners made extensions that have already used the PD allowance
• •Assuming a flat has PD rights (it does not under Part 1 Class A)
• •Building beyond PD limits and discovering the problem when selling