Move
Total: £50,675
- SDLT (HMRC)
- £26,750
- Estate-agent fee
- £6,900
- Survey
- £1,500
- Legal (sale + purchase)
- £2,500
- Removals
- £2,000
- Chain contingency (1.5%)
- £11,025
For homeowners in Redbridge (London Borough of Redbridge). Updated 2026-06-11.
Outer north-east London. Mix of Victorian villas and Edwardian terrace in Wanstead, South Woodford, Snaresbrook; interwar suburban semi-detached in Gants Hill, Barkingside, Hainault. Side returns common in Wanstead and South Woodford; rear extensions dominate the suburban stock.
The borough covers the E11, E18, IG1, IG2, IG3, IG4, IG5, IG6, IG7, IG8 postcode districts. Terraced homes here trade around £530,000 against the borough-wide £460,000 average.
In Redbridge, the average home is valued at £460,000. Moving up by 60% to a £735,000 property triggers approximately £26,750 in Stamp Duty Land Tax (SDLT). By contrast, a 22 m² high-spec rear extension (single storey) here costs around £108,537 all-in. The average home here is around £460,000 (ONS, 2026).
Adjust the inputs to see your scenario. The page updates instantly as you adjust the inputs.
Moving is £57,862 cheaper than extending
Total: £50,675
Rear extension (single storey) — high spec
Total: £108,537
An extension of this type and size could add roughly £59,800 (≈13%) to your home's value — Nationwide Building Society, October 2025.
Where moving starts costing more than the extension you selected. The chart follows your inputs above.
Up to about £1,325,000 of target price, moving is the cheaper route in Redbridge; beyond that line, extending wins.
Decision speed: MHCLG householder statistics, year ending September 2025, excluding agreed extensions of time.
HMRC bands applied to a £735,000 purchase — the default Redbridge trade-up.
| Price band | Rate | SDLT due |
|---|---|---|
| £0 – £125,000 | 0% | £0 |
| £125,000 – £250,000 | 2% | £2,500 |
| £250,000 – £925,000 | 5% | £24,250 |
High specification at typical size, outer London rates, all-in.
| Extension type | All-in cost | vs moving |
|---|---|---|
| Rear extension (single storey) (22 m²) | £108,537 | £57,862 more than moving |
| Rear extension (double storey) (45 m²) | £208,553 | £157,878 more than moving |
| Two-storey side extension (35 m²) | £167,440 | £116,765 more than moving |
| Garage conversion (18 m²) | £43,056 | saves £7,619 vs moving |
| Loft conversion (hip-to-gable) (25 m²) | £67,275 | £16,600 more than moving |
| Over-garage extension (18 m²) | £34,983 | saves £15,692 vs moving |
"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."
Nearby by average property value — useful if you're weighing a move to an adjacent price tier. A comparable trade-up in Enfield would carry about £27,250 of stamp duty — £500 more than in Redbridge.
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 outer London £/m² rates by extension type — industry-estimate midpoints, presented as approximations.