Basement extension in Ealing
Do you need planning permission for a basement extension in Ealing?
Yes — expect a full application and a structural method statement. Basement development is covered by SPD 4 (Residential Extensions), which sets the design rules alongside ordinary planning policy. There is no useful permitted-development route for basements.
Covered by SPD 4 (Residential Extensions), which sets the design rules for basement development; expect a full application and a structural method statement.
Basements are less of a mass-market product here than in constrained central boroughs, but SPD 4 explicitly covers basement development and conservation-area work, so the design and structural case still has to be made properly. Ground conditions vary across the borough; investigation before commitment is non-negotiable. Conservation areas add scrutiny of lightwells and other visible elements.
What actually applies in Ealing
Conservation areas in Ealing
Real · planning.data.gov.ukEvery designated conservation area in Ealing from the official dataset — inside one, permitted development narrows and design scrutiny rises.
- Acton Green
- Acton Park
- Acton Town Centre
- Bedford Park
- Brentham Garden Estate
- Brunswick
- Canalside, northeast part
- Canalside, northwest part
- Canalside, southeast part
- Canalside, southwest part
- Churchfields
- Creffield
- Cuckoo Estate
- Ealing Common
- Ealing Cricket Ground
- Ealing Green
- Ealing Town Centre
- Grange and White Ledges
- Hanger Hill Garden Estate
- Hanger Hill, Haymills Estate
- Hanwell Cemeteries
- Hanwell Clock Tower
- Hanwell Village Green
- Haven Green
- Mill Hill Park
- Montpelier Park
- Mount Park
- Northolt Village Green
- Norwood Green
- Old Oak Lane
- St Mark's Church and Canal
- St Stephen's
Source: planning.data.gov.uk · Open Government Licence. Boundaries are checked at address level by the area report.
Article 4 directions in Ealing
Real · planning.data.gov.ukEaling's Article 4 directions aren't all in the national planning.data.gov.uk geometry, but the borough operates significant ones: directions made in October 2024 remove the permitted development right to convert a house (C3) into a small HMO (C4) — so an HMO conversion needs planning permission — and six conservation areas carry further Article 4 restrictions on householder permitted development. Check the council's Article 4 pages for the position at a specific address.
Source: planning.data.gov.uk · Open Government Licence · 1 directions recorded. Checked at address level by the area report.
Prices: HM Land Registry UK House Price Index, December 2025 · Open Government Licence.
The planning route — PD or permission?
There is no useful permitted development route for basements in practice — assume a full planning application everywhere, with a Basement Impact Assessment covering ground conditions, hydrology, structural methodology and construction management. Camden, Westminster and Islington all limit basements to a single storey in most circumstances and protect listed buildings from excavation almost absolutely.
In a conservation area — which blankets much of prime north-west London, from Hampstead to St John's Wood — there is no permitted-development route to lose, but the visible elements are assessed closely on heritage grounds: lightwells, railings, front-garden changes, rooflights and any external alteration. An Article 4 direction or a listed building can remove the option of excavation altogether.
Party wall procedure is heavier than for any other project: underpinning shared walls triggers awards with detailed method statements on both sides, and neighbour objections — on noise, vibration, structural risk and years of disruption — are the norm rather than the exception. The applications that succeed arrive with the engineering done, not promised.
Permitted development limits — basement extension
| Permitted development | None in practice — assume a full planning application |
| Required technical evidence | Basement Impact Assessment (ground, hydrology, structure, construction management) |
| Depth, in most inner-London boroughs | Single storey in most circumstances |
| Listed buildings | Excavation protected against almost absolutely |
| Party wall procedure | Awards with method statements where underpinning shared walls |
Limits summarise the General Permitted Development Order (Schedule 2, Part 1) as it applies in London. In Ealing, a conservation area, Article 4 direction or listed status changes the route — the panels above show what is designated, and the address check confirms what applies at your property.
How much does a basement extension cost in Ealing?
| Cost per m² (low) | £6,000 |
| Cost per m² (expected) | £8,500 |
| Cost per m² (high — difficult ground / high water table) | £12,000+ |
| Typical project (35–50m² single storey) | £210,000 – £600,000 |
| Professional and consultant fees (add) | 15–25% of build |
Basements carry the widest cost uncertainty of any project — ground conditions and water management can move budgets six figures. Ranges from real project data; VAT excluded. Never commit on a single quote without a ground investigation.
Realistic timeline
| Feasibility, ground investigation, BIA | 3–6 months |
| Planning decision | 10–16 weeks |
| Party wall awards (multiple) | 3–6 months (parallel) |
| Build | 8–14 months |
What catches people out in Ealing
Ground conditions and party wall awards dominate risk. Treating SPD 4 as optional guidance rather than the design frame officers will use is a common preparation gap.
Postcode districts in Ealing
W5 is the heart of the 'Queen of the Suburbs' — the Ealing Common, Ealing Green, Mount Park and Creffield conservation areas, the Hanger Hill Garden Estate and the pioneering Brentham Garden Estate at Pitshanger.
W5 — Ealing & Pitshanger →W13 runs from West Ealing to Northfields, taking in the St Stephen's and Montpelier Park conservation areas.
W13 — West Ealing & Northfields →W7 is Hanwell — the Hanwell Village Green, Hanwell Clock Tower and St Mark's Church and Canal conservation areas, with the Cuckoo Estate's planned cottages nearby.
W7 — Hanwell →W3 covers Acton — the Acton Park, Acton Green and Mill Hill Park conservation areas, with the Ealing side of Bedford Park, often called the world's first garden suburb.
W3 — Acton →UB2 reaches Southall and the Norwood Green conservation area, with its village green and the Grand Union Canal nearby.
UB2 — Southall & Norwood Green →UB1 is Southall in Ealing — dense terraces and mixed tenure with an Hillingdon edge.
UB1 — Southall →UB5 is Northolt on the Ealing–Harrow edge.
UB5 — Northolt →UB6 covers Greenford in Ealing (with a Harrow edge) — interwar and later suburban housing with industrial-edge pockets.
UB6 — Greenford →Basement extension in Ealing, asked straight
Do basements need planning permission in Ealing?
How much does a basement cost?
What does SPD 4 say about basements?
Are basements common in Ealing?
What is the biggest risk?
What applies at your address?
Borough-level rules only narrow it down. Enter a Ealing postcode for the live constraint check — conservation area, Article 4 and sold-price comparables, cited to source.
Need it in writing for one address? A planning permission report for a Ealing property — from £59, or surveyor-reviewed from £295.
Planning Permission Checker provides planning and cost intelligence for early feasibility only. It is not legal, planning, valuation, architectural, structural, or surveying advice. All estimates are indicative and must be verified by qualified professionals before purchase, design, planning submission, or construction.
Cost estimates are indicative only — not a quotation. Final price depends on survey, specification, structure, access, party wall matters, VAT, professional fees, and contractor availability.
Planning outcomes are not guaranteed. Local planning authorities make final decisions.