Area guide · N3
House Extensions in Finchley (N3)
Planning a house extension in Finchley? We design, gain planning permission and build extensions and loft conversions across N3 — Church End, Finchley Central and the streets around Victoria Park. This is Finchley proper: East Finchley (N2) and North Finchley (N12) have pages of their own. Build budgets for a single-storey rear sit at £45,000–£90,000, Barnet Council is the deciding authority, and Barnet's recent N3 decisions are listed further down, with refusals alongside approvals. One free site visit and you'll know precisely where your street stands.
Planning in Finchley
What Barnet Council has approved in Finchley
Barnet's published decisions turn "will they accept it?" from a guess into a lookup. The list on this page covers two Barnet wards, Finchley Church End and West Finchley, and between them they reach a little beyond N3 at both ends: north to the N12 streets around Tally Ho corner, and west to the NW4 roads on the Holders Hill side. So a handful of N12 and NW4 addresses sit among the N3 ones.
What fills it is the everyday work that changes how an N3 house lives: single-storey rears, some replacing a tired conservatory; side extensions along the old passage; and roof extensions, many of them decided as lawful development certificates rather than planning applications. Look at the route beside each decision as well as the outcome. A householder application was needed because something in the scheme went beyond permitted development, or because the house is in one of the conservation areas below.
Recent planning decisions around Finchley
Extension, loft and basement applications decided in Barnet's Finchley Church End and West Finchley wards, 23 Sep 2025 to 22 Sep 2026.
The newest decisions in those wards
- ApprovedSep 2026
Lichfield Grove, N3
Single storey rear extension with 1no. rooflight. Addition of 1no. front and 1no. rear facing rooflights to existing roof
26/1138/HSE · Barnet CouncilHouseholder application
- ApprovedSep 2026
Arden Road, N3
Roof extension involving side dormer window with pitched roof and glazing. Alterations to fenestration including insertion of first floor…
26/3248/192 · Barnet CouncilLawful development certificate
- ApprovedSep 2026
Stanhope Avenue, N3
Single storey rear extension with green roof and new terrace area following demolition of the existing shed. New ground floor side window…
26/1622/HSE · Barnet CouncilHouseholder application
- ApprovedSep 2026
Rosemont Avenue, N12
Single storey rear extension with flat roof and 1no. rooflight following demolition of the existing conservatory. Reinstatement of the…
26/2544/HSE · Barnet CouncilHouseholder application
- ApprovedSep 2026
Manor View, N3
Roof extension involving side/rear wraparound dormer and 1no. front facing rooflight and flat rooflights. Changes to the side fenestration
26/2638/192 · Barnet CouncilLawful development certificate
- ApprovedSep 2026
Station Road, N3
Single storey rear/side extension. Changes to side fenestration including the addition of one first floor window
26/2858/HSE · Barnet CouncilHouseholder application
- ApprovedSep 2026
Ridge Close, NW4
Roof extension with rear dormer window, 2 side facing rooflights. Changes to fenestration; new bifold doors at ground floor level
26/2928/192 · Barnet CouncilLawful development certificate
- ApprovedSep 2026
Wentworth Park, N3
Single storey front, side and rear extension following demolition of the existing garage. Formation of side annexe. First floor rear…
26/2590/HSE · Barnet CouncilHouseholder application
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
Finchley's housing stock — and what works on each
Finchley is a varied patch — village core, Edwardian suburb and Metroland all in one postcode.
Church End. The historic heart of Finchley around the parish church carries Victorian and Edwardian streets with proper proportions — high ceilings, original details, and side alleys begging to be used. The side-return extension (£35,000–£65,000) and the wrap-around (£70,000–£140,000) are the signature schemes, opening dark galley kitchens into wide, light family rooms.
The Victoria Park streets. The Edwardian terraces and semis around Victoria Park are classic family-house territory. Single-storey rears (£45,000–£90,000) and loft conversions add the fourth bedroom and second bathroom these houses always seem to be one short of; the Finchley loft conversion guide goes through the roof options for these streets.
The 1930s semi avenues. Finchley's inter-war streets bring hipped roofs and side passages — ideal for the hip-to-gable loft with rear dormer (£55,000–£90,000) and for side extensions replacing passages and covered ways. Garage conversions (£18,000–£35,000) are the quiet bargain of this stock.
West Finchley and the Dollis Brook side. The streets running down towards the Dollis Brook mix 1930s semis with pockets of later infill, and gardens are noticeably generous. The rear-extension-plus-loft combination works exceptionally well here — and where the garden allows, a garden room adds a working-from-home base without touching the main house.
Finchley Garden Village. The 1910s cottage-style enclave is a conservation area, and deservedly so. Materials, rooflines and boundary treatments all matter here, and the section below explains why even small changes need consent. Extensions still happen; they're simply designed with conservation literacy.
Every street is different. That's the point.
We design to Finchley'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 estimateFinchley's conservation areas, and where Article 4 applies
Barnet has several conservation areas in the two wards this page covers, and they don't all work the same way for an extension.
Finchley Garden Village (designated 1978) and Moss Hall Crescent (1974, at the N12 end of West Finchley ward) each have an Article 4 direction that covers the whole area. Both directions take away the right to extend the house (Part 1, Class A), so a single-storey rear that would often be permitted development elsewhere in N3 needs a planning application there.
Finchley Church End (1979) covers the old centre around the parish church. National conservation-area rules apply across it: no side extensions, no two-storey rear extensions and no larger-home prior approval under permitted development. An Article 4(2) direction made in 2011 goes further on particular houses within it, again including Class A.
College Farm (1989) and Glenhill Close (2001) complete the list. Glenhill Close's Article 4 direction covers walls, fences and gates only, so its houses keep the conservation-area version of the permitted development rules for extensions; planning.data.gov.uk maps no Article 4 direction on College Farm.
A dormer is outside permitted development in every one of them. We check the exact address on Barnet's maps before any drawing starts, and our conservation area guide explains what the design has to answer.
Honest numbers
What a house extension costs in Finchley in 2026
Expect Finchley build costs to fall within these honest, all-in bands — quality labour and materials, with VAT, professional fees and kitchen fit-out excluded:
| Extension type | Typical Finchley cost | On-site time | Usual planning route |
|---|---|---|---|
| Side-return extension | £35,000 – £65,000 | 2–3 months | Often permitted development |
| Single-storey rear | £45,000 – £90,000 | 3–4 months | Often permitted development |
| Kitchen extension (incl. mid-range kitchen) | £55,000 – £110,000 | 3–4 months | Often permitted development |
| Hip-to-gable loft + rear dormer | £55,000 – £90,000 | 6–10 weeks | Usually permitted development |
| Wrap-around extension | £70,000 – £140,000 | 4–6 months | Full application |
| Double-storey rear | £75,000 – £160,000 | 5–7 months | Full application |
| Garage conversion | £18,000 – £35,000 | 4–6 weeks | Usually permitted development |
Per square metre, Finchley pricing holds to the £2,800–£4,200 North London norm, with period-property care nudging Edwardian stock towards the upper half. On those rates a 22m² rear addition prices out at roughly £62,000–£92,000. Your quote — fixed, and itemised down to individual trades — follows the free site visit, and it won't grow between signature and completion.
Permissions, handled
Planning permission in Finchley — what you need to know
A large share of N3 projects proceed without a full application. Semis and terraces carry an automatic right to a 3m single-storey rear extension and detached houses to 4m — and prior approval under the larger home extension scheme can take those limits out to 6m and 8m. Lofts enjoy a generous volume allowance, which is why a rear dormer with rooflights in the front slope so often goes through as a certificate.
You'll need permission for: wrap-arounds, double-storey rears, flats and maisonettes, most work in the conservation areas above, and houses where PD rights are already spent. A standard householder application generally takes Barnet about eight weeks to determine.
Party walls: terraces and semis make the Party Wall Act a fact of life in Finchley — budget £1,000–£2,500 per affected neighbour where surveyors are appointed. We serve the notices and manage the process so it never stalls your build.
Our approach: design to the demonstrated grain of local approvals — and where the project is permitted development, secure a Lawful Development Certificate anyway. It's the document your buyer's solicitor will ask for in five years' time. Our North London guide puts Barnet's rules next to Enfield's and Haringey's if you're comparing areas.
How it works
How it works
- Free site visit — we call at your Finchley home, listen to the plan, and give you straight talk on feasibility, likely cost and the planning path.
- Design & drawings — a complete set of plans with 3D visuals, drawn to suit the bones of your house and the rhythm of your days.
- Planning, handled — Barnet Council receives a complete, well-argued application from us, and we manage every exchange until it's decided.
- Fixed-price build — the construction phase lands with our established North London team and ends with building control sign-off and a clean, complete handover.
Our work
Recent work near Finchley
Closest to home is a job our build team finished in Finchley itself: an Edwardian house converted into three flats, stripped back to brick and extended 3m at the rear on all three floors. For a whole-house brief on a bigger plot, the Hadley Wood case study shows a family home taken from 120m² to 360m². Point us at your plans during the visit and we'll go through them with you.
Questions, answered
Finchley extension FAQs
What does a house extension cost in Finchley?
N3 sits at standard North London rates — roughly £2,800–£4,200/m². That's £45,000–£90,000 for a single-storey rear, £55,000–£90,000 for a hip-to-gable loft and £70,000 upwards for wrap-around schemes, excluding VAT and fees. We confirm with a fixed, itemised quote.
I'm in Finchley Garden Village — can I still extend?
Usually yes, with the right design. The Garden Village is a conservation area with an Article 4 direction over the whole of it, so even a single-storey rear needs a planning application and materials and detailing are scrutinised — but well-mannered extensions do gain consent. We design to the enclave's character from the first sketch.
Can I replace my covered side way with a proper side extension?
Often, yes. A single-storey side extension is permitted development on many Finchley semis within the width and height limits, though not in a conservation area, where it needs planning permission. It's a cost-effective upgrade on Finchley's 1930s stock, and it often pairs with a rear extension in a single build.
Do loft dormers in N3 need planning permission?
Often not — lofts carry a generous PD volume allowance, and a rear dormer with rooflights in the front slope is the format that most often goes through as a certificate. A dormer on the front slope, or any dormer in a conservation area, does need permission. We confirm your roof's remaining allowance, then secure a Lawful Development Certificate for certainty.
What's the realistic timeline for a Finchley application?
Around eight weeks for a standard householder decision once validated; prior-approval applications for larger rear extensions run to a shorter statutory period.
Which parts of Finchley do you cover?
All of N3 — Church End, Finchley Central, the Victoria Park streets and Finchley Garden Village — plus North Finchley, East Finchley and the rest of North London.
What we build in Finchley
The same team designs, gets planning and builds — one fixed, itemised price whichever route your Finchley project takes.
Nearby areas we cover
What clients say
Rated 5.0 on Google
“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.”
“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”
“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.”
“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.”
“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.”
“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.”
Reviews shown word for word from our Google profile. See 9 more client reviews · Read all 16 reviews on Google
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