Move
Total: £125,100
- SDLT (HMRC)
- £84,750
- Estate-agent fee
- £13,200
- Survey
- £1,500
- Legal (sale + purchase)
- £2,500
- Removals
- £2,000
- Chain contingency (1.5%)
- £21,150
Hammersmith and Fulham: is it cheaper to extend or move in 2026?
For homeowners in Hammersmith and Fulham (London Borough of Hammersmith and Fulham). Updated 2026-06-11.
West-inner London. Dense Victorian and Edwardian terrace stock in Fulham (SW6) and Hammersmith (W6); Victorian villa terraces in Brackenbury and Shepherd's Bush (W12); mansion blocks along the river. The classic London Victorian-terrace-with-outrigger geometry is the typical local property for side return extensions.
The borough covers the NW10, SW6, SW10, W6, W12, W14 postcode districts. Terraced homes here trade around £1,320,000 against the borough-wide £880,000 average.
In short
In Hammersmith and Fulham, the average home is valued at £880,000. Moving up by 60% to a £1,410,000 property triggers approximately £84,750 in Stamp Duty Land Tax (SDLT). By contrast, a 12 m² high-spec side return extension here costs around £82,524 all-in. Only 33% of householder planning applications here are decided within 8 weeks — among the slowest in London.
Your numbers
Adjust the inputs to see your scenario. The page updates instantly as you adjust the inputs.
Your result
Extending saves you £42,576
Extend
Side return extension — high spec
Total: £82,524
- Build cost (12 m² × £4,600/m²)
- £55,200
- Professional fees (15%)
- £8,280
- Subtotal
- £63,480
- VAT (20%)
- £12,696
- Contingency (10%)
- £6,348
An extension of this type and size could add roughly £114,400 (≈13%) to your home's value — Nationwide Building Society, October 2025.
Your tipping line
Where moving starts costing more than the extension you selected. The chart follows your inputs above.
Up to about £1,040,000 of target price, moving is the cheaper route in Hammersmith and Fulham; beyond that line, extending wins.
Extending in Hammersmith and Fulham: what's different here
Local planning picture
- Conservation areas
- 44
- Householder decisions within 8 weeks
- 33%
- Build-cost tier
- inner London
- Typical housing stock
- Victorian and Edwardian terraces
Decision speed: MHCLG householder statistics, year ending September 2025, excluding agreed extensions of time.
Worth knowing in Hammersmith and Fulham
- Only 33% of householder planning applications here are decided within 8 weeks — among the slowest in London.
- Hammersmith and Fulham has a borough-wide Article 4 direction removing permitted development rights for basements.
- The average home here is around £880,000 (ONS, 2026).
- Extension types suited to Victorian and Edwardian terraces: Side return extension, Rear extension (single storey), Wrap-around extension, Kitchen extension, Loft conversion (dormer), Loft conversion (mansard).
How the £84,750 stamp duty stacks up
HMRC bands applied to a £1,410,000 purchase — the default Hammersmith and Fulham trade-up.
| Price band | Rate | SDLT due |
|---|---|---|
| £0 – £125,000 | 0% | £0 |
| £125,000 – £250,000 | 2% | £2,500 |
| £250,000 – £925,000 | 5% | £33,750 |
| £925,000 – £1,500,000 | 10% | £48,500 |
What each suitable type costs vs the £125,100 move
High specification at typical size, inner London rates, all-in.
| Extension type | All-in cost | vs moving |
|---|---|---|
| Side return extension (12 m²) | £82,524 | saves £42,576 vs moving |
| Rear extension (single storey) (22 m²) | £124,982 | saves £118 vs moving |
| Wrap-around extension (25 m²) | £108,388 | saves £16,712 vs moving |
| Kitchen extension (22 m²) | £124,982 | saves £118 vs moving |
| Loft conversion (dormer) (18 m²) | £47,093 | saves £78,007 vs moving |
| Loft conversion (mansard) (30 m²) | £103,155 | saves £21,945 vs moving |
Why this comparison matters
"An architect-designed house extension in London may cost between £3,000 and £5,000 per square metre. Elsewhere in the UK, you can expect to pay between £2,000 and £3,500 per square metre."
Frequently asked questions
- Is it cheaper to extend or move in Hammersmith and Fulham?
- At Hammersmith and Fulham's average £880,000 home moving up to £1,410,000, the move costs about £125,100 — including £84,750 of HMRC Stamp Duty. A 12 m² high-spec side return extension runs roughly £82,524 at inner London rates. Extending is cheaper here by about £42,576. Your real figure depends on extension size, specification and planning constraints.
- How long does a side return extension take in Hammersmith and Fulham?
- Allow around 16 weeks on site for a typical side return extension in Hammersmith and Fulham, after design, party wall agreements with neighbours and the council's determination period. A rear extension (single storey) runs nearer 16 weeks. End to end, plan 4–8 months from first call to completion — longer in conservation areas or where structural surveys are needed.
- Will an extension add value to my Hammersmith and Fulham home?
- Nationwide Building Society (October 2025) found that adding a double bedroom can lift a home's value by about 13%, and a full loft conversion plus extension by up to 24%. On a Hammersmith and Fulham average of £880,000, that's roughly £114,400 to £211,200 of capital uplift. Final return depends on the local market, the type of buyer in Hammersmith and Fulham, and your extension's specification.
- Can I live in my home during the extension build?
- Most Hammersmith and Fulham families stay in their home during a single-storey rear or side return extension — the build is contained to the back, and your kitchen is typically rebuilt in 2–3 weeks of disruption. Loft conversions and full wraparounds are harder: expect 4–6 weeks where one floor is unusable. Plan for temporary kitchen arrangements and dust everywhere.
- Can I build a basement in Hammersmith and Fulham?
- Yes, but not under permitted development: London Borough of Hammersmith and Fulham has a borough-wide Article 4 direction removing PD rights for basement development, so every basement needs a full planning application. Local policy limits most schemes to a single storey and around 50% of the garden, with engineer-certified method statements required. Budget inner London basement rates and 6–12 months of works.
- At what price does moving stop making sense in Hammersmith and Fulham?
- Starting from Hammersmith and Fulham's average £880,000 home with a 12 m² high-spec side return extension (£82,524 all-in), the tipping line sits at roughly £1,040,000: buying above that price costs more in SDLT and moving fees than the extension itself. Below it, moving stays the cheaper route. The live chart on this page recalculates the line for your own inputs.
- How much stamp duty would I pay moving up in Hammersmith and Fulham?
- On a typical Hammersmith and Fulham trade-up from £880,000 to £1,410,000 (a 60% step up), Stamp Duty Land Tax (SDLT) is £84,750 — an effective rate of 6.01%. First-time buyers and additional-property buyers pay different rates. Use HMRC's official calculator at tax.service.gov.uk for your exact figure. HMRC Stamp Duty calculator
- What does a typical extension cost in Hammersmith and Fulham in 2026?
- A 12 m² side return extension in Hammersmith and Fulham runs about £83,000 all-in at high specification, on inner London build rates of around £4,600/m². A 22 m² rear extension (single storey) comes to roughly £125,000. All-in figures include 15% professional fees, 20% VAT and a 10% contingency — final cost depends on access, specification and ground conditions.
- How long does planning permission take in Hammersmith and Fulham?
- The statutory determination period for a householder application is 8 weeks. London Borough of Hammersmith and Fulham decided 33% of householder applications within 8 weeks in the year to September 2025 (MHCLG figures, excluding agreed extensions of time) — among the slowest in London. Across London, authorities grant roughly low-to-mid 80s per cent of applications. A householder application costs £548 from April 2026, and a Larger Home Extension prior approval £240.
- Do I need planning permission for an extension in Hammersmith and Fulham?
- Many single-storey rear extensions fall under Permitted Development — no planning permission needed. Hammersmith and Fulham has Article 4 directions in named conservation areas removing PD rights for side, rear and roof extensions, plus a borough-wide HMO Article 4. Conservation areas cover a substantial proportion of the period housing stock. Hammersmith and Fulham has 44 conservation areas, including Bishop's Park, Brackenbury, Crabtree, where PD rights are curtailed. Side extensions, large rear extensions and most wraparounds need full planning regardless. Check the London Borough of Hammersmith and Fulham planning portal first. Open the London Borough of Hammersmith and Fulham planning portal
Compare nearby London boroughs
Nearby by average property value — useful if you're weighing a move to an adjacent price tier. A comparable trade-up in City of London would carry about £79,750 of stamp duty — £5,000 less than in Hammersmith and Fulham.
Methodology and sources
Stamp Duty Land Tax is calculated from the HMRC bands in force for the 2025–26 tax year. Verify any figure against HMRC's official calculator before committing. Extension costs use inner London £/m² rates by extension type — industry-estimate midpoints, presented as approximations.
- MHCLG planning statistics (PS2 dashboard) — householder decision speed, year ending September 2025.
- London 2026 £/m² grid by extension type and tier — Build Team benchmark compiled from BCIS/RICS, FMB and published architect guides (refreshed quarterly).
- Conservation-area counts and Article 4 status — individual London borough councils, verified 2026.
- HMRC SDLT calculator — tax.service.gov.uk/calculate-stamp-duty-land-tax
- GOV.UK Stamp Duty Land Tax guidance — gov.uk/stamp-duty-land-tax
- Nationwide House Price Index (October 2025 release) — value-add commentary attributed to Andrew Harvey, Senior Economist.
- HM Land Registry / ONS UK House Price Index — borough average property values (March 2026 release).