Area guide · EN4
House Extensions in East Barnet (EN4)
Planning a house extension in East Barnet? We design, gain planning permission and build extensions and loft conversions across EN4 — from the village core around St Mary's church to the 1930s avenues near Oak Hill Park. A typical single-storey rear here builds out at £45,000–£90,000, Barnet Council holds the decision-making pen, and its latest decisions in the East Barnet ward are listed further down this page, dated and referenced. Invite us round for a free site visit and we'll spell out what your own street will support.
Planning in East Barnet
What Barnet Council approves, and refuses, in East Barnet
Barnet's decision records show what the council is passing in EN4, which beats guesswork. The ones below come from its East Barnet ward, which stretches from the old village around St Mary's up to the Barnet side of Cockfosters, so a card on Games Road or Heddon Court Avenue belongs here as much as one near the church.
Look at the route line on each card. In this ward much of the roof work goes through as a lawful development certificate, the council's confirmation that a hip-to-gable or rear dormer is permitted development, rather than as a planning application. Single-storey rears turn up both ways: some as certificates, some as prior approval for a deeper extension, some as full householder applications when a side element or extra depth takes them past the permitted limits. Refusals are counted in the totals above the list, and the reasons behind any refusal are on Barnet's register under its reference.
Recent planning decisions around East Barnet
Extension, loft and basement applications decided in Barnet's East Barnet ward, 23 Sep 2025 to 22 Sep 2026.
The newest decisions in those wards
- ApprovedSep 2026
Ridgeway Avenue, EN4
Single storey rear extension with flat rooflights and 2no. roof lanterns
26/3223/192 · Barnet CouncilLawful development certificate
- ApprovedSep 2026
Margaret Road, EN4
Single storey side and rear extension with new rooflight and access steps following demolition of the existing rear projection
26/2735/HSE · Barnet CouncilHouseholder application
- ApprovedSep 2026
Park Road, EN4
Part single, part two storey front, side and rear extensions following demolition of the existing conservatory and garage. Alteration to…
26/2655/HSE · Barnet CouncilHouseholder application
- ApprovedSep 2026
Sambroke Square, EN4
Single storey rear extension
26/2649/HSE · Barnet CouncilHouseholder application
- ApprovedSep 2026
Lawton Road, EN4
Alterations and extensions to roof including insertion of 3no. rear window, 3no. front facing rooflights and new side gable window
26/3119/192 · Barnet CouncilLawful development certificate
- ApprovedAug 2026
Ridgeway Avenue, EN4
Single storey rear extension with 1no. rooflight following demolition of the existing conservatory. Roof extension involving rear dormer…
26/3037/192 · Barnet CouncilLawful development certificate
- ApprovedAug 2026
Ridgeway Avenue, EN4
Roof extension involving rear dormer window, 2no. front facing rooflights and new side gable window. New front porch
26/2396/192 · Barnet CouncilLawful development certificate
- ApprovedAug 2026
Ridgeway Avenue, EN4
Single storey rear extension with a proposed depth of 5.50m, maximum height of 3.50m and an eaves height of 3.00m
26/2409/PNH · Barnet CouncilPrior approval, larger home extension
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
East Barnet's housing stock — and what works on each
East Barnet is older than it looks — a proper village wrapped in Metroland — and the right extension depends on which layer you're in.
The village core around St Mary's. The streets around the old village hold East Barnet's Victorian cottages and earlier houses — smaller footprints, tighter plots, lots of charm. The plays here are the side-return extension (£35,000–£65,000) and modest single-storey rears, designed with period detail so they sit comfortably on the street. Close neighbours mean party wall consents come with the territory; we manage them as standard.
The 1930s hipped-roof semi belt. The defining East Barnet house: bay windows, hipped roof, side passage, decent garden. Two schemes dominate — the hip-to-gable loft with rear dormer (£55,000–£90,000), a staple of the ward's decisions, and the single-storey rear (£45,000–£90,000), often finished with a roof lantern over the kitchen. Do both, in one programme or phased, and you've effectively rebuilt the house around modern family life.
Around Oak Hill Park. The avenues bordering Oak Hill Park carry some of East Barnet's larger inter-war homes on wider plots. These take wrap-arounds (£70,000–£140,000), double-storey rears (£75,000–£160,000) and part single, part two-storey side-and-rear combinations — schemes that add two or three rooms in a single build.
Cul-de-sacs and post-war infill. East Barnet's quieter closes respond well to straightforward rear extensions and garage conversions (£18,000–£35,000) — often the cheapest habitable room you can add in the area.
The Barnet side of Cockfosters. West of Cockfosters station, Games Road, Mount Pleasant and Belmont Avenue are in Barnet's East Barnet ward, so Barnet decides there even though most people would call it Cockfosters. The line with Enfield runs through Heddon Court Avenue and Cat Hill, so on those two roads we check which council a particular house falls to. The eastern tip of the Monken Hadley conservation area also reaches Games Road, which is the one corner of the ward where conservation-area rules apply.
Every street is different. That's the point.
We design to East Barnet'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 East Barnet in 2026
The build ranges below reflect real East Barnet pricing — solid-standard labour and materials, before VAT, professional fees and kitchen fit-out are added:
| Extension type | Typical East Barnet 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 |
For back-of-envelope purposes, East Barnet builds price at £2,800–£4,200 per square metre — the going North London rate. That puts an 18m² rear addition somewhere around £50,000–£75,000 before fees. Once we've done the free site visit, the guesswork stops: you get a fixed, line-by-line quote, and that contract figure is exactly what you'll pay.
Permissions, handled
Planning permission in East Barnet — what you need to know
Plenty of East Barnet projects skip the full application. The permitted development baseline gives semis and terraces 3m of single-storey rear depth and detached houses 4m; apply for prior approval under the larger home extension scheme and the ceiling lifts to 6m and 8m. Lofts carry a generous volume allowance too, which is how many of EN4's hip-to-gable conversions avoid a full application.
Where permission is needed: part two-storey side-and-rear schemes, wrap-arounds, double-storey rears, flats, and houses whose PD rights have already been used up. Expect roughly eight weeks between validation and a decision on a standard householder application.
"Approved subject to conditions" — the usual wording on a householder consent — is normal, not a warning sign. Conditions are usually routine: matching materials, building to the approved drawings, sensible working hours. We design so the conditions stay routine.
Party walls: semis and cottages mean the Party Wall Act applies to most East Barnet projects — budget £1,000–£2,500 per affected neighbour where surveyors are appointed. We prepare and serve the notices as part of the service. And wherever a scheme proceeds under permitted development, we obtain a Lawful Development Certificate, so your paperwork is bulletproof when you sell. How Barnet's approach compares with Enfield's next door is set out in our North London borough guide.
How it works
How it works
- Free site visit — we visit your East Barnet home, hear what you're hoping for, and tell you plainly what will work, what it'll cost and how the consent route looks.
- Design & drawings — a full drawing pack with 3D visuals, designed around your rooms, your garden and your routines.
- Planning, handled — we compile the application, lodge it with Barnet Council and stay on it until the decision is in.
- Fixed-price build — our own North London build team carries the job through to building control sign-off and a spotless handover.
Our work
Recent work near East Barnet
Fresh from our build team's North London diary, and not far from East Barnet: a full house transformation in Hadley Wood, taking a family home from 120m² to 360m². The details are in our Hadley Wood case study; bring your wish-list to the site visit and we'll work through it with you.
Questions, answered
East Barnet extension FAQs
What's a sensible budget for an extension in East Barnet?
At North London rates of £2,800–£4,200/m², expect £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 or part two-storey schemes — excluding VAT and fees. Garage conversions start around £18,000. We confirm with a fixed quote after a free visit.
Can I put a roof lantern on my rear extension?
Yes. A lantern on a flat-roofed single-storey rear is a standard detail and can sit within permitted development when the extension itself does. It transforms the light in a kitchen-diner and rarely causes planning difficulty when the overall scheme is compliant; the height of the lantern above the flat roof is the detail to get right.
My semi has a hipped roof — how much loft space can I actually gain?
A hip-to-gable conversion with a rear dormer typically yields a proper double bedroom plus en-suite. On an unextended semi it usually goes through as lawful development under the loft volume allowance of 50 cubic metres, which is why so many of East Barnet's loft decisions are certificates rather than planning permissions.
Could I combine a side and rear extension in one project?
Often it's the smartest sequencing — one build, one set of scaffolding, one round of disruption. Part single, part two-storey side-and-rear schemes need a full application, and Barnet looks hardest at the first-floor side element: its set-back from the front, its roof and the gap it leaves to the boundary.
Will I need party wall agreements?
If you share a wall or build near the boundary — which covers most of East Barnet's semis and cottages — yes. Allow £1,000–£2,500 per affected neighbour where surveyors are appointed. We handle the notices and keep the process off your plate.
Is East Barnet in a conservation area?
Mostly not. None of Barnet's conservation areas is centred on East Barnet, but the eastern tip of the Monken Hadley conservation area reaches Games Road on the Cockfosters side. Parts of the old village still have real historic character, so we check your exact address against Barnet's conservation map at the free consultation, before any design work begins.
What we build in East Barnet
The same team designs, gets planning and builds — one fixed, itemised price whichever route your East Barnet project takes.
- Kitchen extensions in East Barnet
- Side return extensions in East Barnet
- Double-storey & wrap-around in East Barnet
- Loft conversions in East Barnet
- Orangeries in East Barnet
- Garden rooms & offices in East Barnet
Checking the rules for East Barnet first?
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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