Basement extension in Hammersmith and Fulham
Do you need planning permission for a basement extension in Hammersmith and Fulham?
Yes — everywhere in the borough. A borough-wide Article 4 direction in force since April 2018 has removed permitted development rights for basement excavation, so every basement needs a full planning application and must meet the council's basement policies on extent, structural method and neighbour impact. There is no permitted-development shortcut for basements here.
A borough-wide Article 4 removes basement PD rights, so every basement needs full planning permission.
Basements are the borough's defining householder control, not a rare special case. The Article 4 direction applies across the whole borough, so the consent question is never whether permitted development might still apply — it is whether the scheme can clear the council's policies on extent, structure and impact with a full Basement Impact Assessment. Parallel directions also restrict certain commercial-to-residential conversions and small HMOs, but those are separate from householder excavation; for homeowners the basement Article 4 is the one that rewrites the project from day one.
What actually applies in Hammersmith and Fulham
Conservation areas in Hammersmith and Fulham
Real · planning.data.gov.ukEvery designated conservation area in Hammersmith and Fulham from the official dataset — inside one, permitted development narrows and design scrutiny rises.
- 3B
- Barclay Road
- Barons Court
- Bishops Park
- Bradmore
- Brook Green
- Central Fulham
- Cleverly Estate
- Colehill Gardens
- Coningham and Lime Grove
- Crabtree
- Dorcas Estate
- Fitzgeorge and Fitzjames
- Fulham Park Gardens
- Fulham Reach
- Gunter Estate
- Hammersmith Broadway
- Hammersmith Grove
- Hammersmith Odeon
- Hammersmith Town Hall
- Hurlingham
- Imperial Square & Gasworks
- Ingersoll and Arminger
- Lakeside/Sinclair/Blythe Road
- Melrose
- Moore Park
- Old Oak & Wormholt
- Olympia and Avonmore
- Parson's Green
- Putney Bridge
- Queen's Club Gardens
- Ravenscourt & Starch Green
- Sands End
- Sedlescombe Road
- Shepherds Bush
- St. Mary's
- St. Peter's Square
- Studdridge Street
- The Billings & Brompton Cutting
- The Mall
- Turneville/Chesson
- Walham Green
- Walham Grove
- Westcroft Square
- Wood Lane
…plus 3 further designated areas.
Source: planning.data.gov.uk · Open Government Licence. Boundaries are checked at address level by the area report.
Article 4 directions in Hammersmith and Fulham
Real · planning.data.gov.ukHammersmith and Fulham's Article 4 directions don't appear in the national planning.data.gov.uk geometry yet, but the borough operates significant ones: a borough-wide direction in force since April 2018 removing permitted development rights for basement excavation (so every basement needs planning permission), plus directions restricting office and storage to residential conversion and small HMOs. Check the council's Article 4 register for the definitive position.
Source: planning.data.gov.uk · Open Government Licence. 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 Hammersmith and Fulham, 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 Hammersmith and Fulham?
| 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 Hammersmith and Fulham
Because the national planning-data geometry does not yet hold this borough's Article 4 directions, an area report can understate the basement position — always confirm against the council's own Article 4 register as well. Ground conditions, party wall awards on both flanks and construction-management conditions on spoil and hours are the other reliable sources of cost and delay.
Postcode districts in Hammersmith and Fulham
W6 runs from the Brook Green and Hammersmith Grove conservation areas to the riverside at Crabtree and Fulham Reach.
W6 — Hammersmith & Brook Green →W12 centres on Shepherd's Bush, with the Wood Lane and Old Oak & Wormholt conservation areas and long terrace runs towards the Goldhawk Road.
W12 — Shepherd's Bush →W14 covers the Olympia and Avonmore, Barons Court and Queen's Club Gardens conservation areas and a high share of mansion-block flats.
W14 — West Kensington & Olympia →SW6 is prime Fulham terrace and mansion stock — the Hurlingham, Parson's Green, Walham Green, Moore Park and Sands End conservation areas.
SW6 — Fulham →Basement extension in Hammersmith and Fulham, asked straight
Do I need planning permission for a basement in Hammersmith and Fulham?
How much does a basement cost here?
Why doesn't the free area report always show the basement Article 4?
What evidence does a basement application need?
Are basements still common in the borough?
What applies at your address?
Borough-level rules only narrow it down. Enter a Hammersmith and Fulham 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 Hammersmith and Fulham 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.