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 the projects currently clearing in East Barnet are single-storey rears with roof lanterns and combined side-and-rear extensions. Invite us round for a free site visit and we'll spell out what your own street will support.
Live planning data
What Barnet Council is actually approving right now
Because we log every residential planning decision across North London, you get to see exactly what Barnet is passing rather than relying on guesswork. In the most recent decision window, EN4 recorded six residential approvals, and two of them are East Barnet roads:
- East Walk, EN4 — single-storey rear extension with a roof lantern and patio alterations (approved subject to conditions)
- Ashurst Road, EN4 — part single, part two-storey side and rear extension with rooflights (approved subject to conditions)
The same EN4 pool also shows hip-to-gable loft conversions being approved repeatedly — Haslemere Avenue and Rosslyn Avenue among recent examples — which makes sense given the postcode's deep stock of hipped-roof semis. Borough-wide, Barnet approved 63 residential schemes in the same two-week window.
Read together, the message for East Barnet is clear: the council is comfortable with glazed single-storey rears — East Walk's roof lantern went through with standard conditions — and with more ambitious side-and-rear combinations, as Ashurst Road's part two-storey scheme shows. If your plan looks like either, you're working with the grain of recent decisions. That's exactly how we design.
Source: Barnet Council's open planning records. Treat these as a barometer of local decision-making — they aren't our builds, and the outcome of any application always hangs on its own particulars.
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), which the EN4 approvals record shows going through again and again, and the single-storey rear (£45,000–£90,000), increasingly finished with a roof lantern, as approved on East Walk. 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 side-and-rear combinations like Ashurst Road's — 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.
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 why EN4's hip-to-gable conversions keep clearing.
Where permission is needed: part two-storey schemes like Ashurst Road's, 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 — and the recent record of 63 approvals in a fortnight borough-wide shows well-prepared schemes moving through steadily.
"Approved subject to conditions" — the phrase attached to both East Walk and Ashurst Road — 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 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 long-vetted North London builders carry 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: a full house transformation taking a family home from 120m² to 360m², a 55m² garden room with kitchen and bathroom, and an Edwardian conversion in Finchley, a short drive west. Bring your wish-list to the site visit and we'll match it against the jobs we've finished nearby.
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 — and East Barnet has fresh local precedent: the East Walk approval was a single-storey rear extension with a roof lantern and patio alterations. Lanterns transform the light in a kitchen-diner and rarely cause planning difficulty when the overall scheme is compliant.
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. EN4's recent record shows these approved repeatedly — Haslemere Avenue and Rosslyn Avenue among them — usually as lawful development under the generous loft volume allowance.
Could I combine a side and rear extension in one project, like Ashurst Road?
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 Ashurst Road's consent shows Barnet passing exactly this in East Barnet.
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?
Parts of the area have real historic character, so we never assume either way — we check your exact address against Barnet's conservation map at the free consultation, before any design work begins.
Nearby areas we cover
Ready to see what's possible on your street?
Free site visit anywhere in East Barnet, honest feasibility advice and a fixed, itemised price — design, planning and build handled end to end.
Or call us — 020 3051 9430