What Does Planning Permission Cost for London Home Projects? A Guide to Planning Fees in 2025

When London homeowners budget for a home extension, loft conversion, or other residential project, they often focus on the construction cost and overlook the full cost of obtaining planning permission. The statutory application fee is just the starting point -- the real cost of achieving planning approval includes architect fees, potentially a planning consultant, and a range of specialist surveys and supporting documents that planning officers increasingly require.

The statutory planning application fees in England are set by the government and are the same for all English local authorities (including all London Boroughs). From December 2023, fees were increased significantly:

Householder application (extensions, loft conversions, alterations to existing dwellings):

• Fee: £258 per application

Full planning application (new dwellings, change of use, or works that cannot be covered by a householder application):

• Fee: £578 for up to 0.1 ha (the relevant category for most London residential projects)

Prior Approval (larger home extensions under the Prior Approval procedure):

• Fee: £258 per application

Listed Building Consent:

• No statutory fee (Listed Building Consent applications are free in England)

Note: householder applications cover most standard London home extension and loft conversion projects. Where a project involves creating a new dwelling (such as a flat over a garage or a new house in the back garden), a full planning application fee applies.

The statutory fee is a small part of the total cost. The largest cost component is typically the architect's fee for preparing the planning application drawings and documents.

For a standard London householder planning application, a RIBA-registered architect typically charges:

• Simple rear extension (standard specification, straightforward site): £2,500--£5,000
• Complex extension (conservation area, difficult site, detailed design): £5,000--£12,000
• Loft conversion (dormer or mansard requiring planning): £3,500--£8,000
• Double-storey or wrap-around extension: £5,000--£15,000
• Full design and build package including planning and technical stages: fees typically 8--15% of construction cost

These fees typically cover the design drawings, planning application form, and the Design and Access Statement (required for most London applications in conservation areas or involving listed buildings).

For straightforward householder applications in non-sensitive locations, an architect alone can usually handle the planning process. A planning consultant adds value where:

• The site is in or near a conservation area or adjacent to listed buildings
• The proposed development is policy-sensitive (e.g., a large basement, a significant height increase, or a loss of amenity for neighbours that the council is likely to scrutinise)
• A pre-application advice (PAD) meeting with the planning officer is advisable
• The application has been refused and is being appealed

Planning consultant fees for London residential projects typically range from £2,000--£8,000 for supporting a planning application, and £5,000--£20,000 for handling a planning appeal.

Planning officers in London Boroughs increasingly require specialist surveys and reports to accompany planning applications. Common requirements include:

Arboricultural survey and tree constraints plan: required where the site has trees covered by a Tree Preservation Order (TPO) or within a conservation area. Cost: £500--£2,000.

Ecological survey: required where the site or building may support protected species (bats, birds). Initial bat survey: £600--£1,500. If bats are found, a full survey and mitigation strategy may cost £2,000--£5,000+.

Heritage and townscape assessment: required in conservation areas and for development near listed buildings. Cost: £1,000--£4,000.

Flood Risk Assessment (FRA): required in Zone 2 or Zone 3 flood zones. Cost: £800--£3,000.

Basement Impact Assessment (BIA): required by many London Boroughs for basement excavation projects. Cost: £3,000--£8,000+ (prepared by a structural engineer).

Transport or parking statement: sometimes required for larger developments affecting traffic or parking. Cost: £1,000--£3,000.

In many London Boroughs, approved planning applications trigger a liability to pay the Community Infrastructure Levy (CIL). CIL is charged per square metre of new floorspace and varies significantly by borough -- inner London boroughs tend to have higher CIL rates. CIL rates in London boroughs in 2025 range from nil to over £500/m2 for some uses.

Extensions and loft conversions to existing dwellings are typically exempt from CIL where the applicant occupies the property as their only or main home (self-build exemption). This exemption must be claimed before the commencement of works. Always check with your borough before starting.

A realistic total planning-stage budget for a mid-range London extension (rear extension in a conservation area, requiring a planning application) might look like:

• Architect (design and planning stage): £5,000--£10,000
• Planning application fee: £258
• Pre-application advice (optional but advisable in sensitive areas): £200--£500 (charged by the council)
• Arboricultural survey (if trees affected): £800--£1,500
• Heritage/townscape statement (conservation area): £1,500--£3,000
• Party wall surveyor pre-appointment notice service: £0--£500

Total planning stage cost: £7,000--£16,000 before any construction work begins.

Understanding this upfront investment helps London homeowners budget realistically and avoid being surprised by pre-construction professional fee costs.

rcbGroup works with experienced architects and planning consultants and can help you understand what the planning process is likely to involve for your specific project. Contact our team to discuss.