Area guide · NW4
House Extensions in Hendon (NW4)
Planning a house extension in Hendon? We design, gain planning permission and build extensions and loft conversions across NW4 — from the 1930s semi heartland to the Edwardian terraces around Hendon Central. The going rate to build a single-storey rear is £45,000–£90,000, applications go through Barnet Council, and the borough's most-approved project type right now — the hip-to-gable loft conversion — is tailor-made for Hendon's hipped-roof semis. Let us walk your 1930s semi with you on a free site visit — by the end of it you'll know exactly what your street will take.
Live planning data
What Barnet Council is approving right now
We follow each residential planning decision issued in North London — meaning the pattern is visible before you spend a penny on drawings, with no guessing about what the council will accept. In the most recent two-week decision window, Barnet Council approved 63 residential schemes across the borough, and two project types dominate the list:
- Hip-to-gable loft conversions with rear dormers — approved again and again, most of them as lawful development rather than full planning, because the borough's huge stock of hipped-roof 1930s semis is made for them
- Single-storey rear extensions — many with roof lanterns, many replacing tired conservatories — going through under permitted development or with light conditions
That borough-wide pattern matters more in Hendon than almost anywhere, because NW4 is precisely the housing it's built on. Street after street of bay-fronted, hipped-roof semis means Barnet's two most-approved schemes are also Hendon's two most natural ones. If that's the project you have in mind, you're in deeply well-trodden territory — and we design to that grain.
Source: Barnet Council's open planning register. What you're seeing is the borough-wide approvals pattern, not our own portfolio — and a pattern is not a promise: every application is decided on its individual details.
Local knowledge
Hendon's housing stock — and what works on each
Hendon reads as one suburb on a map, but it's really three or four distinct markets — and the right extension depends on which one you're in.
The 1930s semi heartland (most of NW4). Hendon's signature stock: hipped-roof, bay-fronted semis with side passages and proper gardens, built in the great interwar push along the Northern line. This is textbook hip-to-gable and 6-metre-rear territory. A hip-to-gable loft with rear dormer converts the wasted hip into a full double bedroom and en-suite for £55,000–£90,000. A single-storey rear extension — 3m deep under standard permitted development, up to 6m with larger-home prior approval — opens the kitchen to the garden for £45,000–£90,000. Do both, together or phased, and a three-bed semi becomes a five-bed family house without anyone changing school.
Edwardian terraces around Hendon Central. The older streets near the station are narrower, with rear closet wings — classic side-return extension territory (£35,000–£65,000), reclaiming the dead alley beside the kitchen for a full-width kitchen-diner, or a wrap-around (£70,000–£140,000) if you take the rear as well. Terraces mean party wall agreements with both neighbours; we manage that paperwork as part of the job.
The Burroughs and the historic core. The Burroughs is Hendon's civic and historic heart — Georgian frontages, the old town hall, the library and the Middlesex University campus give this pocket a character the rest of NW4 doesn't share. Older, more sensitive properties here reward careful design and honest materials, and planning is less of a formality. We check every address against Barnet's conservation map before any design work starts.
The Brent Cross effect. With the vast Brent Cross regeneration reshaping the area next door, the maths in Hendon increasingly favours extending over moving: add 20–40m² to the house you own, in an area on the way up, and you keep your street, your schools and your commute while the house grows around you.
Every street is different. That's the point.
We design to Hendon'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 Hendon in 2026
Genuine Hendon build figures sit in the bands below — well-executed labour and materials, with VAT, professional fees and kitchen fit-out on top:
| Extension type | Typical Hendon 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 |
Hendon builds at the standard North London rate of £2,800–£4,200 per square metre — straight multiplication puts a 20m² rear addition at £56,000–£84,000 of build cost. After the free site visit we commit to a fixed, fully itemised price, and it stays put: no creep between contract and completion.
Permissions, handled
Planning permission in Hendon — what you need to know
Most Hendon extensions don't need a full planning application. The PD baseline grants 3m of rear extension depth on semis and terraces and 4m on detached homes; through the larger home extension scheme that stretches to 6m (8m detached), with the council consulting your neighbours under prior approval instead of running a full application. Loft conversions enjoy a generous volume allowance, which is exactly why hip-to-gable schemes fill Barnet's approvals list as lawful development.
Where you do need permission: double-storey and wrap-around schemes, flats and maisonettes, anything in a conservation area — where permitted development rights are restricted — and houses where a previous owner has already used the PD allowance, which is common on streets that have been extending since the 1980s. Allow around eight weeks for Barnet to determine a standard householder application.
Party walls: Hendon is overwhelmingly semi-detached and terraced, so the Party Wall Act applies to most projects. Budget £1,000–£2,500 per affected neighbour if surveyors are appointed — and have the friendly conversation over the fence early; it keeps things smooth and inexpensive. We serve the notices for you.
Our approach: we design to what Barnet Council demonstrably approves, and when the lawful development route makes better sense we'll secure the certificate for you — the piece of paper that heads off awkward questions at remortgage or sale.
How it works
How it works
- Free site visit — we walk your hipped-roof Hendon semi (or your Edwardian terrace near the station), hear the plan, and respond with honest numbers and a clear route.
- Design & drawings — proper drawings and 3D views, composed around your floor plan and the way your family uses it.
- Planning, handled — we take the whole Barnet Council process off your hands, from preparing the file to chasing the decision.
- Fixed-price build — execution by our dependable North London crew, wrapped up with building control certification and a genuinely tidy exit.
Our work
Recent work near Hendon
Among our build team's latest North London completions: 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 neighbouring Finchley. Say the word at your site visit and we'll show you whichever of these best matches your own scheme.
Questions, answered
Hendon extension FAQs
What should I budget for a house extension in Hendon?
Around £45,000–£90,000 for a single-storey rear extension, £55,000–£90,000 for a hip-to-gable loft and £18,000–£35,000 for a garage conversion — excluding VAT and fees, on NW4 build rates of £2,800–£4,200 per square metre. Every quote we give is fixed and itemised after a free site visit.
Can I really extend 6 metres without full planning permission?
On most Hendon semis, yes. The larger home extension scheme allows rear extensions up to 6m (8m on detached houses) through prior approval, where Barnet Council consults your neighbours instead of running a full application. We confirm your house qualifies before any design work begins.
Is a hip-to-gable loft the right move for a 1930s Hendon semi?
Almost always. It's the most-approved scheme type in Barnet right now, NW4's hipped roofs are the exact stock it suits, and the generous permitted development volume allowance typically delivers a double bedroom plus en-suite without a full application.
Does the Brent Cross regeneration change the case for extending?
It strengthens it. With the area beside NW4 improving and the cost of moving high, adding space to the house you already own is increasingly the better-value route — and well-extended semis hold their value strongly in improving areas.
What about older houses near The Burroughs?
Hendon's historic core calls for a more sensitive touch — proportions, rooflines and materials carry real weight, and planning is less of a formality than on the 1930s streets. We check your address against Barnet's conservation map at the free consultation, before you spend anything.
Which parts of Hendon do you cover?
All of NW4 — Hendon Central, West Hendon, the streets around The Burroughs and Middlesex University, and the Brent Cross side — plus neighbouring Mill Hill, Golders Green, Finchley and Edgware.
Nearby areas we cover
What clients say
Rated 5.0 on Google
“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.…” read the full review
“Really impressed with the entire project. The side extension and conservatory have been finished to a very high standard and the team made the process straight forward and stress-free. It’s transformed the space and added so much value, would definitely recommend.”
“Brilliant experience with the extension company, transparent from the word go. Completed a double story extension for me and I couldn’t be more pleased. Thank you”
“I got the extension company to do a bathroom refurb for us a January they done a great job they managed to fit in a large shower as well as a bath”
Reviews shown word for word from our Google profile. Read all 8 reviews on Google
Free site visit
Ready to see what's possible on your street?
Free site visit anywhere in Hendon, 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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