Area guide · N20

House Extensions in Totteridge (N20)

Planning a house extension in Totteridge? We design, gain planning permission and build extensions across Totteridge Village, Totteridge Lane, the Common and the lanes between the green-belt fields, and in Woodside Park, the N12 side of the same council ward. 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.

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Council

London Borough of Barnet

Typical single-storey rear

£55k–£110k

Standard householder decision

~8 weeks

Conservation area covers Totteridge Village and much of Totteridge Lane, with Article 4 directions

Green belt wraps the fields and the Common

Planning in Totteridge

What Barnet Council approves in Totteridge

Part of our job is reading the planning registers, so you can see what the council is passing rather than guessing. The decisions below come from Barnet's Totteridge & Woodside ward, and that ward is more mixed than its name suggests. It runs from the big houses on Totteridge Common and in the Village, through the suburban N20 streets south of Totteridge Lane, to Woodside Park's N12 roads and a fringe of NW7, so a conservation-area rework and a hip-to-gable on a semi can sit side by side in the list. Read the address before reading anything into the outcome.

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 work in neighbouring Whetstone are often unavailable, or unwise, here. Barnet has also made two Article 4 directions on the conservation area. The 1972 direction covers mapped parts of it and takes away the right to enlarge the house without an application, so there even a modest single-storey rear needs planning permission. The 2008 direction covers a short run of houses in Totteridge Village and brings changes to their street-facing elevations under control. 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.

Recent planning decisions around Totteridge

Extension, loft and basement applications decided in Barnet's Totteridge & Woodside ward, 23 Sep 2025 to 22 Sep 2026.

Decided

Approved

Refused

The newest decisions in those wards

RefusedSep 2026
Totteridge Common, N20
Enlargement, improvement, and alteration to the existing dwellinghouse, including 2no. single storey rear extensions, and a single storey…
26/2771/192 · Barnet CouncilLawful development certificate
ApprovedSep 2026
Laurel Way, N20
Conversion of the existing garage into habitable room, insertion of window to replace garage door. Changes to side fenestration. Removal…
26/2384/192 · Barnet CouncilLawful development certificate
ApprovedSep 2026
Totteridge Village, N20
Single storey rear extension. New first floor rear roof terrace with privacy screens. Changes to fenestration; replacement windows to…
26/2603/HSE · Barnet CouncilHouseholder application
ApprovedSep 2026
West Hill Way, N20
Demolition of existing garage and rear extension. Erection of single storey side and part single part two storey rear extension with…
26/2240/HSE · Barnet CouncilHouseholder application
RefusedSep 2026
Greenway Close, N20
Part single, part two storey side and rear extension following demolition of the existing conservatory. Roof extension involving including…
26/0660/HSE · Barnet CouncilHouseholder application
ApprovedSep 2026
Totteridge Common, N20
Single storey rear conservatory extension. Extension to existing raised terrace.
26/2554/HSE · Barnet CouncilHouseholder application
RefusedSep 2026
Longland Drive, N20
Single storey rear extension with a proposed maximum depth of 8.00 metres, maximum height of 3.30 metres and eaves height of 3.00 metres…
26/2782/PNH · Barnet CouncilPrior approval, larger home extension
ApprovedAug 2026
Cissbury Ring North, N12
Roof extension involving rear dormer window with juliette balcony, 3no. front facing rooflights and new side gable window. Ground floor…
26/2991/192 · Barnet CouncilLawful development certificate

Look a reference up on the council’s own register: Barnet Council planning search.

Source: GLA Planning London Datahub, 23 Sep 2025 – 22 Sep 2026. Data updated September 2026. This list last changed 23 September 2026. The datahub can lag a council’s own register by a few weeks.

These are council decisions on applications in these wards, shown as local planning context. They are not necessarily projects undertaken by us, and they are not our approval rate. Planning outcomes depend on your specific property and proposal.

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. South of Totteridge Lane, roads such as Southway, Greenway, Laurel Way and Ventnor Drive lie outside the conservation area and the green belt, so 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. A lawful development certificate is only granted if every part of the scheme is within the limits, though, and the ward's certificate decisions include refusals as well as approvals, so we check every element against the limits before applying.

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 estimate

Woodside Park (N12): the other half of the ward

The council ward is called Totteridge & Woodside, and its southern half is a different place from the lanes: Woodside Park, the N12 streets around Woodside Park station on the Northern line. Barnet decides here too, and none of these streets is in a conservation area or the green belt, so the full permitted development allowance generally applies.

West of the station is a set of roads named after Sussex downland and villages: Cissbury Ring, Chanctonbury Way, Poynings Way, Lullington Garth, Rodmell Slope and Northiam among them. Two patterns run through the recent decisions there. Many houses have a garage at the side, and the usual scheme turns it into a room or replaces it with a single-storey side and rear extension. And the ground falls away behind a lot of these houses, so rear extensions come with steps down to the garden and a raised patio. That detail matters, because a raised platform more than 300mm high is not permitted development: an extension that would otherwise need no application can end up as a householder application because of the terrace outside it. We design the levels first for that reason. Roofs here take a rear dormer or a hip-to-gable, usually confirmed by a lawful development certificate.

East of the station, Woodside Park Road and Woodside Grove fall in Barnet's Woodhouse ward instead, and their decisions are on our North Finchley page. The Totteridge premium in the price table below reflects the big houses on the lanes; for Woodside Park, the North London baseline of £2,800–£4,200 per square metre is the better guide.

Honest 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. For how Barnet's constraints compare with Enfield's and Haringey's, see our North London extension guide.

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

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 our own North London build team, finishing with building control approval and a handover that leaves nothing behind.

Thinking bigger in Totteridge

Totteridge briefs run large. Along the Ridgeway and the lanes, detached houses on paddock-scale plots suit projects planned in decades rather than rooms: the double-storey rework, the basement leisure floor, the extension paired with a full internal remodel. The design conversation for that class of work starts with the green belt that laps the lanes.

It is exactly the territory of our large and luxury extensions service. The bands are set out honestly in the luxury extension cost guide, and the proportion rules that govern the lanes are unpacked in our guide to extending in the green belt.

Our work

Recent work near Totteridge

A recent commission for our build team was a full house transformation in Hadley Wood, taking a family home from 120m² to 360m² — the scale of rework Totteridge plots invite. It's in our Hadley Wood case study; tell us what you're weighing up when we visit and we'll talk it through.

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. Parts of it are also under Article 4 directions, and on those the right to extend without an application has gone altogether. We check your exact address against Barnet's conservation and Article 4 maps 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.

Does Woodside Park have the same restrictions as Totteridge?

No. Woodside Park's N12 streets share the council ward with Totteridge but sit outside the conservation area and the green belt, so the ordinary permitted development rules apply: a 3m rear on a semi or 4m on a detached house, doubled through prior approval, and a hip-to-gable loft within the volume allowance. Sloping gardens are the usual complication, because a raised terrace can tip a scheme into needing an application.

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.

What we build in Totteridge

The same team designs, gets planning and builds — one fixed, itemised price whichever route your Totteridge project takes.

Checking the rules for Totteridge first?

Nearby areas we cover

Whetstone · Barnet · Mill Hill · North Finchley · Finchley

What clients say

Rated 5.0 on Google

5.0 from 16 Google reviews

“The Extension Company built a 5m single storey rear extension on our Victorian terrace in Crouch End. Went down the permitted development route so no planning application needed, which they explained up front and saved us months. Kitchen-diner now opens onto the garden with sliding doors. £87k all in, matched the quote.”

Harry PopeSingle-storey rear extension, Crouch End · Google review · June 2026

“From the initial site visit onwards to my property in Barnet, we felt that the team actually listened to what we wanted. They suggested a few changes to the layout that we hadn't considered, and those changes have made a huge difference. Would definitely use again and recommend”

Ceri JenkinsBarnet · Google review · September 2026

“Used The Extension Company for a loft conversion on our semi detached in Barnet and couldn't be happier. They explained what was possible at the first visit, sorted the planning side, and gave a fixed price with no surprises at the end. The hip-to-gable and rear dormer gave us a big double bedroom with an en-suite. Tidy, professional and finished on schedule. Would recommend to anyone in North London thinking about a loft conversion.”

Billie CampbellHip-to-gable & rear dormer loft conversion, Barnet · Google review · June 2026

“We had been putting off our loft conversion for years because the whole process felt overwhelming. The team made it much easier than expected and handled the drawings, planning and build for us. We now have a lovely extra bedroom and shower room.”

Daniel LangleyLoft conversion · Google review · September 2026

“Our wrap-around extension has completely transformed the ground floor. We now have the open plan kitchen and family space we wanted without losing all of the garden. Thanks to everyone involved.”

Lesley ClarkWrap-around extension · Google review · September 2026

“Really pleased with the work from The Extension Company. We had our extension done in Hampstead and the whole experience was excellent. Great communication from start to finish, The quality of the finish is excellent and we’re really happy with the result. Would definitely recommend them if you’re thinking about an extension.”

Alban PershqefaExtension, Hampstead · Google review · August 2026

Reviews shown word for word from our Google profile. See 9 more client reviews · Read all 16 reviews on Google

Free site visit

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 by the Pine Grove team.

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