Skip to content
ProjectsCost GuidesGuidesAnswersInsightsAbout
Get a Quote

Barnet · London

Wraparound Extension in Barnet

North London borough with large 1930s semis ideal for loft conversions and wraparound extensions.

N2N3N11N12N20NW4NW7NW11EN4EN5
Typical Barnet cost
£90k–£200k
Timeline
1422 wks
Build estimator

Get a 60-second estimate

Indicative range
£45,000£120,000
814 weeks on site

Barnet

Wraparound Extension specialists across Barnet.

We deliver wraparound extension projects across the full Barnet postcode set — N2, N3, N11, N12, N20, NW4, NW7, NW11, EN4, EN5. North London borough with large 1930s semis ideal for loft conversions and wraparound extensions.

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 Barnet 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 Barnet 2026.

ConfigurationCost rangeTimeline
Standard wraparound (3m side + 3m rear)£90,000£125,00014–17 wks
Larger wraparound (3m side + 5m rear)£115,000£155,00016–19 wks
Premium wraparound with structural glass£145,000£200,00018–22 wks

Local advantage

Eight years of wraparound extension work in Barnet.

Familiarity with Barnet's planning officers, party wall surveyors and approved inspectors cuts weeks off the approval timeline. We deliver consistent quality across all 10 postcodes the borough covers.

Recent Barnet work

Wraparound Extension examples.

Wraparound kitchen extension in Barnet
Open plan family room in Barnet
Full glazed rear wall in Barnet
Kitchen island with pendant lights in Barnet
Compare

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.

Builderr fixed price
£145,000
a wraparound extension in Barnet · no provisional sums
Typical builder + variations
£174,000
+£29,000 vs Builderr (≈20% overrun)
Cowboy outfit + cost creep
£210,250
+£65,250 vs Builderr (≈45% overrun)
CriterionBuilderrTypical London builderCowboy outfit
Labour modelDirectly employed team (PAYE)Mixed subcontract gangsDay-rate cash labour
PricingFixed-scope itemised quoteEstimate + provisional sumsVerbal price + variations
Design & engineeringIn-house architect + SEOutsourced, separate billingBuilder draws on the back of an envelope
Planning + LDC handledYes — included in priceOften charged extraBuilder asks you to apply
Party wall surveyorsInstructed by usYour responsibilitySkipped (illegal)
Building controlPlans + site inspections booked by usBuilding Notice routeNot registered
Project managementDedicated PM, weekly photo updatesForeman doubles upOwner-manager juggles 5 jobs
Payment scheduleStage payments against signed-off milestonesWeekly invoicesCash up front
Insurance£10M PL + 10yr structural warranty£2–5M PL onlyNo documented cover
Snags at handover<3 typical20–30 typicalWalk-off mid-job common
Variation creep0% — fixed scope+15–25% over original quote+40%+ regularly
Bottom line

Save £29,000£65,250 on a wraparound extension in Barnet.

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 Barnet.

How much does a wraparound extension cost in Barnet?+

Wraparound Extension projects in Barnet typically cost £90,000–£200,000. Barnet sits across postcodes N2, N3, N11, N12; local rates align with the wider London market.

Do wraparound extensions in Barnet need planning permission?+

North London borough with large 1930s semis ideal for loft conversions and wraparound extensions. 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 Barnet postcodes?+

Yes — we deliver wraparound extension projects across all Barnet postcodes including N2, N3, N11, N12, N20, NW4, NW7, NW11, EN4, EN5.

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 Barnet wraparound extension quote.

Senior consultant call within one business hour. Fixed-scope quote for your Barnet project — no provisional sums.