Planning Permission for London Renovations: What Needs Consent and How to Get It

Planning permission is one of the most misunderstood aspects of London residential renovation. Homeowners routinely assume that work to their own property is their own affair, and are surprised to find that extensions, loft conversions, changes to windows, and even some internal alterations require consent from the local planning authority. Equally, works that homeowners assume are complex planning applications sometimes fall under permitted development and require no application at all.

This guide covers the planning permission framework for London residential renovation — what requires consent, what is permitted development, and how to navigate the process efficiently.

The two-tier system: planning permission vs permitted development

Permitted Development (PD) rights give homeowners the ability to carry out certain works without a formal planning application. PD rights are granted by the Town and Country Planning (General Permitted Development) (England) Order 2015 (as amended), and are subject to size, height, and design limits.

The important limitation: PD rights can be removed or restricted by: - Article 4 Directions: Local authorities can remove PD rights across an area (commonly Conservation Areas) or for specific types of works. In much of inner London — Kensington, Chelsea, Westminster, Islington, Camden — Article 4 Directions are widespread and remove many PD rights that apply elsewhere. - Listed Building status: Listed Buildings require Listed Building Consent (LBC) for any works that affect their character as a listed structure, both external and internal. PD rights do not apply to works requiring LBC. - Conditions on previous planning permissions: Previous planning consents sometimes include conditions removing permitted development rights for future works.

The first step of any renovation is to check whether the property is in a Conservation Area, whether it is Listed, and what Article 4 Directions apply. All of this information is available from the local planning authority's website.

Works that are typically permitted development (outside Conservation Areas)

Single-storey rear extensions: Up to 4 m deep from the rear wall (for detached houses) or 3 m deep (for semi-detached and terraced houses), not exceeding 4 m in height, not wider than the original house. Under the Neighbour Consultation Scheme (the prior approval process for larger extensions), depths up to 8 m (detached) or 6 m (semi/terrace) are possible subject to neighbour notification. Note: these dimensions apply outside London Conservation Areas; within them, rear extensions often require full planning.

Loft conversions: Roof alterations that do not extend beyond the highest part of the existing roof, with a volume increase of up to 50 m³ (detached) or 40 m³ (other houses). Hip-to-gable and rear dormer conversions may fall within PD if within the volume limit. Roof extensions must not be visible from the road in front of the original house.

Side extensions: A single storey, up to half the width of the original house, maximum 4 m height. Two storeys above ground level are not permitted development for side extensions.

Internal alterations: Most internal works (removing non-load-bearing walls, replanning layouts, installing kitchens and bathrooms, internal finishes) do not require planning permission. Building Regulations approval is a separate matter (structural work, electrical, plumbing, fire safety) but not planning.

Windows and doors: In most locations outside Conservation Areas, replacing windows and doors like-for-like is permitted development. Adding new windows in a habitable room on an upper floor side elevation may require planning (overlooking restrictions).

Works that always require full planning permission

Change of use: Converting a single dwelling into flats, or a commercial property to residential, always requires planning permission.

Extensions in Conservation Areas: Any extension visible from a public highway in a Conservation Area typically requires full planning. Even extensions that would be PD outside the Conservation Area are controlled within it.

Two-storey rear extensions: Two-storey (or higher) rear extensions are not permitted development. They require a full planning application.

Works to Listed Buildings: Any works affecting the character of a Listed Building — both external and internal — require Listed Building Consent in addition to planning permission for external changes.

New buildings on the site: Any new structure separate from the house (other than small permitted development outbuildings within PD limits) requires planning permission.

Changes to the external appearance in Conservation Areas: Replacement windows, changes to brickwork or render, new doors, and alterations to boundary walls often require consent in Conservation Areas, especially where Article 4 Directions apply.

The Certificate of Lawful Development (CLD)

Where works are believed to be permitted development, a Certificate of Lawful Development provides formal confirmation from the planning authority that the works are lawful. It is not required — but it is strongly advisable for:

• —Any works where PD status is uncertain
• —Works that will affect the property's sale value (solicitors on conveyancing will ask for evidence that works were lawfully carried out)
• —Works in areas where Article 4 Directions may apply but their scope is uncertain

A CLD application is simpler and cheaper than a full planning application (typically £206 fee for a residential CLD application in England as of 2024). Processing time is typically 8 weeks.

Full planning application process

Where planning permission is required, the process is:

Pre-application advice: Most London planning authorities offer a pre-application discussion service (£200–£500 for a residential consultation). This is strongly advisable before submitting a formal application for anything complex — extensions in Conservation Areas, basements, larger loft conversions. The planning officer's informal guidance can prevent an application that is destined to fail and can identify the design changes needed to achieve consent.

Application submission: A planning application includes drawings (existing and proposed, to scale), a planning statement (explaining the proposal and why it is acceptable against policy), and supporting documents as required (Design and Access Statement, Heritage Statement for Conservation Areas, Arboricultural Assessment for works near protected trees, Basement Impact Assessment for basement works in affected boroughs).

Statutory period: Local planning authorities have 8 weeks to determine a householder planning application. In practice, many exceed this — major London boroughs often take 10–13 weeks. Extensions of time can be agreed with the applicant.

Conditions: Planning permissions are typically granted with conditions — hours of working, materials to match the existing, no occupation until certain works are complete. Conditions must be complied with, and some require prior approval before works begin (pre-commencement conditions).

Appeals: If a planning application is refused, the applicant can appeal to the Planning Inspectorate. An appeal adds 3–6 months to the process. In some cases (where refusal was unreasonable) the applicant can recover costs.

Conservation Area considerations

Conservation Area status does not prevent development — it means that development must preserve or enhance the character and appearance of the Conservation Area. Works that are refused are typically refused because they harm the character of the area, not because any change is unacceptable.

In practice, the following are commonly achievable in London Conservation Areas with appropriate design: - Rear extensions in materials matching the original building - Loft conversions with sympathetic dormers (typically rear-facing only, set back from the eaves) - Double-glazed timber replacement windows matching original profiles - New or replacement front doors in period-appropriate design

The following are commonly refused: - uPVC windows and doors - Front extensions or any works visible from the street that alter the property's streetscape contribution - Roof extensions visible above the original eaves on the front elevation - Modern materials (render, metal cladding) on the front elevation of a brick building

Listed Buildings

Listed Building Consent is required for any works that affect the character of a Listed Building. This includes: - Any external alterations - Internal alterations that affect historic fabric (removing original joinery, fireplaces, plaster cornices, floor boards) - Repairs using non-traditional materials

Works to Listed Buildings require a heritage statement and typically a Heritage Impact Assessment from a conservation architect or heritage consultant. Conservation officers have significant discretion and the quality of the application (and the consultant advising) materially affects the outcome.

Grade II* and Grade I Listed Buildings have more stringent requirements than Grade II. Unauthorised works to a Listed Building are a criminal offence.

Building Regulations: the separate approval track

Building Regulations approval is distinct from planning permission. Building Regulations set standards for structural safety, fire, thermal performance, ventilation, drainage, and accessibility. The following works typically require Building Regulations approval regardless of planning status:

• —Structural alterations (removing walls, installing beams)
• —Extensions (thermal, structural, drainage compliance)
• —Loft conversions (fire escape, structural, thermal)
• —New bathrooms (drainage, ventilation)
• —Rewiring or new electrical circuits
• —New boilers or heating systems
• —Replacement windows (thermal performance, egress)

Building Regulations approval is obtained from either the local authority Building Control (LABC) or an approved inspector (private building control body). Work must be inspected at key stages.

Cost and programme implications

Pre-application advice fee: £200–£500. Householder planning application fee (England): £258 (as of April 2024). CLD application fee: £206. Architect/planning consultant fees for application preparation: £2,000–£8,000 depending on complexity. Listed Building application (with heritage consultant): £3,000–£15,000.

Planning decision (standard householder): 8–13 weeks. CLD decision: 6–8 weeks. Planning appeal: 3–6 months additional.

The planning process is the variable that most often delays a London renovation. Starting the planning application at the point the design is sufficiently resolved — rather than waiting until the contractor is on board — is the single most effective programme management action available.