Brixton · SW2 · SW9 · Lambeth

House Extensions in Brixton

Rear extensions, side returns and wraparounds for Brixton's Victorian terraces. We handle Lambeth Council planning, party wall notices and Building Regulations from first survey to final snag — with honest SW2 & SW9 cost benchmarks up front.

Get Advice & Costs Call 07799 057452
Lambeth planning
PD checks, conservation pockets & Certificates of Lawfulness
Party wall handled
Notices served correctly, on time
JCT contracts
Staged payments, never more than 20% upfront
Free site survey
Honest advice on what your plot allows
Open-plan kitchen extension in a Brixton Victorian terrace

An Extension Builder That Knows SW2 & SW9

If you have had builders round already, you know the problem: one quotes £48,000 with no breakdown, another quotes £130,000 and neither explains the difference. The difference is almost entirely specification — not quality of construction — and an honest builder shows you exactly where the money goes before you commit.

We work with Brixton's Victorian terraces every week: solid brick walls, 150-year-old clay drainage that runs in unexpected directions, and Lambeth's mix of Permitted Development streets and conservation pockets around Brixton Hill and Acre Lane. We survey first, flag the risks early, and quote with a full breakdown.

  • Rear & Side Return Extensions
  • Wraparound Extensions
  • Two-Storey Additions
  • Extension + Full Renovation Projects
Discuss Your Extension

What a House Extension Costs in Brixton (2026)

SW2 & SW9 benchmarks including VAT, assuming a standard Victorian terrace with normal ground and access. A free site survey gives you an accurate, itemised figure.

Rear extension, 4m × 4m, standard spec
£55,000–£68,000
Side return infill, standard spec
£48,000–£65,000
Wraparound, mid spec
£90,000–£125,000
Two-storey rear extension
£95,000–£140,000

Want a personalised range first? Try our free Extension Cost Calculator — or read the full Brixton cost breakdown.

How Your Brixton Extension Runs

1. Free site survey

We assess your plot, drainage and ground conditions, and check whether your street falls in one of Lambeth's conservation pockets.

2. Design & planning

Drawings, structural calculations and either a Certificate of Lawfulness or a full planning application to Lambeth Council, managed for you.

3. Party wall & Building Regs

Party Wall Notices served on adjoining neighbours at least two months before work starts. Building Control applications and inspections handled throughout.

4. Build & handover

A single-storey rear extension typically takes 10–16 weeks on site under a written JCT contract with staged payments. We finish with a full snagging walkthrough.

Planning an Extension in Brixton?

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Brixton House Extension FAQs

Do I need planning permission for a rear extension in Brixton?

Many single-storey rear extensions on Brixton terraces fall under Permitted Development, but parts of Brixton Hill, Acre Lane and other pockets sit within conservation areas where a full application to Lambeth Council is needed. Either way, apply for a Certificate of Lawfulness (around £206) for legal certainty. We check your address at the free survey.

How much does a house extension cost in Brixton?

SW2 & SW9 benchmarks for 2026, including VAT: a 4m × 4m single-storey rear extension at standard spec £55,000–£68,000; a 4m × 5m mid-spec with structural glazing £68,000–£85,000; a side return infill £48,000–£65,000; a wraparound £90,000–£125,000; a two-storey rear extension £95,000–£140,000.

How long does a rear extension take?

The build typically takes 10–16 weeks on site. The total programme — architect, planning, party wall and Building Regulations — is typically 9–14 months where full planning permission is required.

What hidden costs should I budget for?

The common ones in Brixton's Victorian stock: deeper foundations if the ground is poor (£5,000–£15,000), rerouting 150-year-old clay drainage (£3,000–£8,000), and party wall surveyor fees if a neighbour dissents (£1,500–£3,000 per neighbour). A good builder flags these risks before you sign, not after the ground is open.

How much value does an extension add in SW2 & SW9?

The premium for a four-bedroom house over a three-bedroom on the same street is typically £100,000–£160,000 in Brixton. A well-executed rear extension creating that fourth bedroom or an open-plan ground floor costs £55,000–£85,000 — the arithmetic usually works.

Want the deep dive? Read our full Brixton extension cost guide, the Victorian side return guide and the wraparound extension guide.

Ready for an Honest Answer About Your Extension?

Free survey, straight advice, no pressure. If an extension is not right for your house, we will tell you.

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