Westminster · London
Wraparound Extension in Westminster
Central borough with listed and conservation stock — interior and basement work dominates.
Westminster
Wraparound Extension specialists across Westminster.
We deliver wraparound extension projects across the full Westminster postcode set — W1, SW1, NW1, NW8. Central borough with listed and conservation stock — interior and basement work dominates.
A wraparound extension combines a side return and rear extension into a single L-shaped footprint. It's the largest possible single-storey ground floor on a Victorian or Edwardian terrace and turns the entire ground floor into an open-plan family hub — kitchen, dining and living rooms all flowing into each other with full garden views.
Every Westminster project includes a free desk-based planning assessment before we quote. We know the local planning officers, party wall surveyors and approved inspectors by name.
Costs
Wraparound Extension cost in Westminster 2026.
| Configuration | Cost range | Timeline |
|---|---|---|
| Standard wraparound (3m side + 3m rear) | £90,000–£125,000 | 14–17 wks |
| Larger wraparound (3m side + 5m rear) | £115,000–£155,000 | 16–19 wks |
| Premium wraparound with structural glass | £145,000–£200,000 | 18–22 wks |
Local advantage
Eight years of wraparound extension work in Westminster.
Familiarity with Westminster's planning officers, party wall surveyors and approved inspectors cuts weeks off the approval timeline. We deliver consistent quality across all 4 postcodes the borough covers.
Recent Westminster work
Wraparound Extension examples.
Builderr vs other London builders.
The construction industry has a wide distribution of operators. Here's what changes between a directly-employed, fixed-scope outfit and the alternatives.
| Criterion | Builderr | Typical London builder | Cowboy outfit |
|---|---|---|---|
| Labour model | Directly employed team (PAYE) | Mixed subcontract gangs | Day-rate cash labour |
| Pricing | Fixed-scope itemised quote | Estimate + provisional sums | Verbal price + variations |
| Design & engineering | In-house architect + SE | Outsourced, separate billing | Builder draws on the back of an envelope |
| Planning + LDC handled | Yes — included in price | Often charged extra | Builder asks you to apply |
| Party wall surveyors | Instructed by us | Your responsibility | Skipped (illegal) |
| Building control | Plans + site inspections booked by us | Building Notice route | Not registered |
| Project management | Dedicated PM, weekly photo updates | Foreman doubles up | Owner-manager juggles 5 jobs |
| Payment schedule | Stage payments against signed-off milestones | Weekly invoices | Cash up front |
| Insurance | £10M PL + 10yr structural warranty | £2–5M PL only | No documented cover |
| Snags at handover | <3 typical | 20–30 typical | Walk-off mid-job common |
| Variation creep | 0% — fixed scope | +15–25% over original quote | +40%+ regularly |
Save £29,000–£65,250 on a wraparound extension in Westminster.
Industry data (FMB, RICS, Which? Trusted Trader 2024) shows the average London construction project overruns by 18–22% on cost and 25–35% on time. Fixed-scope contracts with a single accountable team eliminate that variance. The savings above assume a typical project at £145,000.
FAQ
Wraparound Extension in Westminster.
How much does a wraparound extension cost in Westminster?+
Wraparound Extension projects in Westminster typically cost £90,000–£200,000. Westminster sits across postcodes W1, SW1, NW1, NW8; local rates align with the wider London market.
Do wraparound extensions in Westminster need planning permission?+
Central borough with listed and conservation stock — interior and basement work dominates. We carry out a free desk-based planning assessment for your specific address before quoting, identifying whether permitted development, prior approval, or full planning applies.
Do you work across all Westminster postcodes?+
Yes — we deliver wraparound extension projects across all Westminster postcodes including W1, SW1, NW1, NW8.
How much does a wraparound extension cost in London?+
Typically £90,000–£200,000 depending on size, spec and glazing. Most projects sit in the £110–150k range fully fitted.
Do I need planning permission for a wraparound?+
Almost always yes — wraparounds usually exceed PD limits in volume and depth.
Get a Westminster wraparound extension quote.
Senior consultant call within one business hour. Fixed-scope quote for your Westminster project — no provisional sums.
Other types in Westminster
Explore other build types in Westminster.
Wraparound Extension across London