Harrow · London
Wraparound Extension in Harrow
Suburban borough with 1930s semis — hip-to-gable lofts and rear extensions common.
Harrow
Wraparound Extension specialists across Harrow.
We deliver wraparound extension projects across the full Harrow postcode set — HA1, HA2, HA3, HA5, HA7, HA8. Suburban borough with 1930s semis — hip-to-gable lofts and rear extensions common.
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 Harrow 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 Harrow 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 Harrow.
Familiarity with Harrow's planning officers, party wall surveyors and approved inspectors cuts weeks off the approval timeline. We deliver consistent quality across all 6 postcodes the borough covers.
Recent Harrow 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 Harrow.
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 Harrow.
How much does a wraparound extension cost in Harrow?+
Wraparound Extension projects in Harrow typically cost £90,000–£200,000. Harrow sits across postcodes HA1, HA2, HA3, HA5; local rates align with the wider London market.
Do wraparound extensions in Harrow need planning permission?+
Suburban borough with 1930s semis — hip-to-gable lofts and rear extensions common. 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 Harrow postcodes?+
Yes — we deliver wraparound extension projects across all Harrow postcodes including HA1, HA2, HA3, HA5, HA7, HA8.
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 Harrow wraparound extension quote.
Senior consultant call within one business hour. Fixed-scope quote for your Harrow project — no provisional sums.
Other types in Harrow
Explore other build types in Harrow.
Wraparound Extension across London