Area guide · N20
House Extensions in Totteridge (N20)
Planning a house extension in Totteridge? We design, gain planning permission and build extensions across one of North London's premier addresses — Totteridge Village, Totteridge Lane, the Common and the lanes between the green-belt fields. A single-storey rear here usually builds for £55,000–£110,000, Barnet Council decides the applications, and the schemes that succeed are design-led full applications — double-storey rears, wrap-arounds and whole-house reworks rather than off-the-peg boxes. The conversation starts with a free site visit, where we'll walk the plot with you and set out what it can genuinely take.
Live planning data
What Barnet Council is actually approving right now
Part of our job is watching the planning registers: every residential decision in North London gets recorded, so you can see what the council is passing rather than guessing. In the most recent decision window, N20 recorded five residential approvals — a mix of dormer roof extensions and part single, part two-storey side and rear schemes — and Barnet Council approved 63 residential schemes borough-wide over the same fortnight. The backdrop is a council that approves good schemes at volume.
Totteridge itself plays by different rules from the rest of N20, and it pays to understand why. Much of the Village and Totteridge Lane sits within a conservation area, with green belt wrapping the fields and the Common — so the permitted-development shortcuts that drive approval numbers in neighbouring Whetstone are often unavailable, or unwise, here. Schemes on the Lane succeed as full applications decided on design quality: proportion, materials, and how the house reads from the lane and across the open land behind it. That's not a barrier — it's a brief. Substantial, ambitious extensions are approved in Totteridge; they're designed, not templated.
Source: Barnet Council's published planning decisions. The figures sketch the local approvals climate rather than our own portfolio — and bear in mind that every application stands or falls on its particular facts.
Local knowledge
Totteridge's housing stock — and what works on each
Totteridge is small, green and remarkably varied — and the right scheme depends on which part you're in.
Totteridge Village and Totteridge Lane (the conservation area). Large detached houses on generous plots, from period homes to substantial later rebuilds. This is where Totteridge's signature projects happen: double-storey rear extensions (£90,000–£200,000), wrap-arounds (£85,000–£175,000), basements and whole-house reworks that re-plan the entire ground floor. In the conservation area the council weighs materials, roof form and street presence carefully — schemes win on drawings that respect the lane.
Totteridge Common and the green-belt edge. Houses backing onto or sitting within the green belt face a different test: policy resists additions that are disproportionate to the original house. The answer is usually a carefully judged extension that spends the allowance where it adds most value — or, where rights are tight, a design-led case showing the openness of the green belt is preserved. We read these constraints early, before you fall in love with a scheme that can't fly.
The streets towards Whetstone. At the eastern end of N20, near Totteridge & Whetstone station, the stock shifts to bay-fronted 1930s semis and the rules shift with it — hip-to-gable lofts with rear dormers (£65,000–£110,000) and single-storey rears (£55,000–£110,000) are the staples, often under permitted development, exactly as the wider N20 approvals pattern shows.
Modern closes and infill. Tucked off the Lane are pockets of later housing where the conservation overlay may not apply and conventional rear and roof schemes work well. We confirm street by street rather than assume.
Every street is different. That's the point.
We design to Totteridge's stock and to what the council demonstrably approves — not to a template. A free site visit tells you what your house can take.
Get my free estimateHonest numbers
What a house extension costs in Totteridge in 2026
Totteridge build costs carry a premium over the North London baseline — typically 20–25% more — reflecting the scale of the houses, conservation-grade materials and the specification these homes warrant. Realistic all-in build ranges, excluding VAT, professional fees and kitchen fit-out:
| Extension type | Typical Totteridge cost | On-site time | Usual planning route |
|---|---|---|---|
| Side-return extension | £45,000 – £80,000 | 2–3 months | PD outside the conservation area; otherwise full application |
| Single-storey rear | £55,000 – £110,000 | 3–4 months | PD on many plots; design-led in the conservation area |
| Kitchen extension (incl. mid-range kitchen) | £65,000 – £135,000 | 3–4 months | As above |
| Hip-to-gable loft + rear dormer | £65,000 – £110,000 | 6–10 weeks | PD towards Whetstone; full application on the Lane |
| Wrap-around extension | £85,000 – £175,000 | 4–6 months | Full application |
| Double-storey rear | £90,000 – £200,000 | 5–7 months | Full application |
| Garage conversion | £22,000 – £45,000 | 4–6 weeks | Usually permitted development |
Expect £3,400–£5,200 per square metre in Totteridge, against the wider North London range of £2,800–£4,200. The difference buys the detailing, glazing and materials these houses deserve — and that conservation officers expect to see. After a free site visit you'll get a quote that's both fixed and fully itemised — nothing vague, nothing left to drift.
Permissions, handled
Planning permission in Totteridge — what you need to know
The fundamentals still apply. Under permitted development a semi or terrace can take a 3m single-storey rear extension and a detached house 4m; secure prior approval through the larger-home scheme and those depths grow to 6m and 8m. Lofts carry a generous volume allowance. On the Whetstone side of N20 those routes work daily, and a standard householder application typically clears Barnet's desk in about eight weeks.
But in the conservation area and green belt, strategy changes. Conservation-area status restricts what can be done without permission and raises the design bar for everything else; green-belt policy resists disproportionate additions over the original house. In practice, most Totteridge schemes go in as full applications, and the winning ones are won at the drawing stage — proportion, materials, landscape. We treat the planning constraints as the design brief. Where any element can be secured as permitted development, we still recommend a Lawful Development Certificate for clean paperwork at resale.
Party walls: many Totteridge houses are detached, so formal party wall awards are rarer than in terraced streets — but excavating foundations near a boundary can still trigger the Party Wall Act. Where it applies, budget £1,000–£2,500 per affected neighbour if surveyors are appointed. We manage the notices as standard.
How it works
How it works
- Free site visit — we spend time at your Totteridge house, listen to your ambitions, and set out frankly what's achievable, what it should cost and how the planning route runs — conservation and green-belt constraints included.
- Design & drawings — plans and 3D imagery worked up to conservation-area standard and fitted to the way your household actually lives.
- Planning, handled — every form, drawing and supporting document goes to Barnet Council under our name, and we steer the application through to its decision.
- Fixed-price build — construction by the North London crew we've vetted over years, finishing with building control approval and a handover that leaves nothing behind.
Our work
Recent work near Totteridge
Recent commissions for our build team across North London include a full house transformation taking a family home from 120m² to 360m² — the scale of rework Totteridge plots invite — plus a 55m² garden room with kitchen and bathroom and an Edwardian conversion in nearby Finchley. Tell us what you're weighing up when we visit and we'll pull out the case studies that speak to it.
Questions, answered
Totteridge extension FAQs
What do extensions cost at Totteridge's end of the market?
Budget £3,400–£5,200/m² — a 20–25% premium on the North London baseline. A single-storey rear typically runs £55,000–£110,000, a double-storey rear £90,000–£200,000, and whole-house reworks beyond that. Figures exclude VAT and fees; we confirm with a fixed quote after a site visit.
Is my house inside the Totteridge conservation area?
The conservation area takes in Totteridge Village and much of Totteridge Lane, but boundaries matter — two houses a few hundred metres apart can face quite different rules. We check your exact address against Barnet's conservation map before any design work starts.
Can I extend a house in the green belt?
Usually yes, within limits — green-belt policy resists additions that are disproportionate to the original house. The craft is in spending that allowance where it transforms how the house lives, and presenting the case well. We assess your remaining headroom at the first visit.
Will my Totteridge project need a full planning application?
Most do, and that's no bad thing. With conservation and green-belt overlays, the certain route is a well-argued full application — Barnet decides householder schemes in about eight weeks, and design quality is what carries the day here.
Are basements and double-storey extensions realistic in Totteridge?
Yes — on plots this size, double-storey rears and basements are often the most coherent way to add serious space, particularly where ground-level footprint is constrained by policy. Both go in as full applications, with proper structural and drainage design behind them.
Do I need party wall agreements for a detached house?
Often not — but not never. Excavation close to a neighbouring structure can trigger the Party Wall Act even with a gap between houses. Where it applies, allow £1,000–£2,500 per affected neighbour; we handle the notices end to end.
Nearby areas we cover
Ready to see what's possible on your street?
Free site visit anywhere in Totteridge, honest feasibility advice and a fixed, itemised price — design, planning and build handled end to end.
Or call us — 020 3051 9430