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Greenwich · SE3 · SE7 · SE9

House Extensions in Greenwich

South-east borough mixing Georgian terraces and post-war semis — varied planning constraints. Single and double-storey extensions delivered as a fixed-scope design and build package.

Typical Greenwich cost
£50k–£220k
Timeline
1020 weeks

Postcodes covered

SE3SE7SE9SE10SE18
Build estimator

Get a 60-second estimate

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

Quick answer

Builderr delivers single-storey, double-storey and wraparound extensions across Greenwich — SE3, SE7, SE9, SE10, SE18 and SE28. Typical Greenwich extension cost £55,000–£170,000 over 11–22 weeks. Blackheath's Georgian and Victorian stock requires heritage-grade design; Eltham's 1930s semis take wraparounds well. Outside conservation zones, Greenwich retains strong PD rights and routinely approves 6m rear extensions under prior approval.

Greenwich conservation areas include West Greenwich, Maritime Greenwich, Blackheath, Charlton Village and Eltham. The World Heritage Site buffer adds further constraint on streets near the river.

Greenwich

House Extensions specialists across Greenwich.

We deliver house extensions projects across the full Greenwich postcode set — SE3, SE7, SE9, SE10, SE18. South-east borough mixing Georgian terraces and post-war semis — varied planning constraints.

Every Greenwich project includes a free desk-based planning assessment before we quote, so you know upfront whether permitted development, prior approval, or full planning applies to your specific address. Our local project manager for Greenwich has detailed knowledge of the planning department's preferences, the conservation area boundaries, and the common construction details for the prevailing housing stock here.

Quotes for Greenwich house extensions are fixed-scope after a site survey, valid for 60 days, and never carry provisional sums or open-ended day rates. Every project includes our 10-year structural warranty and 12-month defects period.

Planning in Greenwich

Local planning rules for house extensions in Greenwich.

Greenwich's conservation areas include West Greenwich, East Greenwich, Westcombe Park (Blackheath), Charlton Village and Eltham. The Maritime Greenwich UNESCO World Heritage Site adds an extra layer of planning sensitivity. The council's Local Plan is design-focused; planners insist on matching materials and traditional detailing in heritage areas. Modern rear extensions can be approved if they read as secondary to the host building. Pre-application consultation is recommended for any extension or roof addition.

Our planning team handles the full submission for Greenwich addresses including drawings, Design and Access Statements where required, and pre-application consultation with the council. We tell you whether your house extension is permitted development, prior approval, or full planning before you sign anything.

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
£135,000
a house extension in Greenwich · no provisional sums
Typical builder + variations
£162,000
+£27,000 vs Builderr (≈20% overrun)
Cowboy outfit + cost creep
£195,750
+£60,750 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 £27,000£60,750 on a house extension in Greenwich.

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 £135,000.

FAQ

House Extensions in Greenwich.

How much does a house extension cost in Greenwich?

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Most house extensions projects in Greenwich cost £50,000–£220,000 depending on size, spec and structural complexity. Inner London postcodes typically sit toward the upper end; outer borough projects trend mid-range. All Builderr Greenwich quotes are fixed-price with no provisional sums.

Do I need planning permission for a house extension in Greenwich?

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Planning rules vary across Greenwich. We check permitted development eligibility, conservation area status and any Article 4 directions affecting your specific postcode before quoting. Many house extensions fall under permitted development, but conservation areas and listed buildings need full planning.

How long does a house extension take in Greenwich?

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Typical timeline is 10–20 weeks on site, plus 4–8 weeks for design, structural engineering and approvals. If full planning is required (conservation areas, mansards, larger extensions), add 8–12 weeks for the planning decision before site start.

Do you have house extension references in Greenwich?

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Yes — we maintain a live reference list for Greenwich and can connect you with two or three completed clients within the borough. We've delivered projects across nearly every Greenwich postcode since 2022, so most prospective clients can visit a completed project nearby.

What's included in a Builderr house extension quote in Greenwich?

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Every Greenwich quote covers structural design, party wall notices and surveyor coordination, planning or prior approval submission where required, building control, full build, snagging and a 10-year structural warranty. Kitchen units, sanitaryware and bespoke finishes are itemised separately so you can flex spec without losing fixed-price certainty on the build.

Get a Greenwich house extension quote.

Senior consultant call within one business hour. Free desk-based planning assessment for SE3, SE7, SE9 and surrounding postcodes. Fixed-scope price — no provisional sums.