House Extensions · NW4 Hendon
Barnet protects the Hendon Burroughs and Church Farm conservation areas around the historic St Mary's core, alongside standard suburban householder control across the rest of NW4.
Working across the whole borough rather than just this area? See house extensions in Barnet.
House extensions in Hendon are dominated by single-storey rear and side-return additions on NW4's inter-war semis and terraces around hendon, with, with double-storey and wrap-around schemes where the plot allows. Barnet Council weighs depth, height and neighbour daylight; many extensions across Hendon, Brent Street, Hendon Central, West Hendon fringe are Permitted Development, which we confirm with a Lawful Development Certificate before you build.
The whole spectrum — rear extensions, side returns, wraparounds, double-storey, basement digs. Planning-led design with detailed technical phase, ideal for inter-war semis and terraces around hendon, with typical of Hendon.
Across Hendon, Brent Street, Hendon Central, West Hendon fringe in NW4, the dominant property is inter-war semis and terraces around hendon, with mansion flats, post-war estates and some edwardian houses. That stock shapes what house extension drawings looks like here: the right approach for a period terrace differs from a mansion-block flat or a new-build, and Barnet Council judges each on design quality and neighbour impact. We survey the specific Hendon property, confirm the planning route — Permitted Development, a Lawful Development Certificate, or full planning — and draw a council-ready set tailored to the NW4 streetscape.
Housing stock in NW4: Inter-war semis and terraces around Hendon, with mansion flats, post-war estates and some Edwardian houses.
Within the district: Hendon, Brent Street, Hendon Central, West Hendon fringe.
Streets we know in NW4: the streets around Hendon Central and Brent Street, the Park Road area and the inter-war terraces toward West Hendon. Each road has its own building line, boundary treatment and precedent that Barnet Council weighs when assessing a house extension drawings scheme.
Conservation areas: Hendon Burroughs / St Mary's, Church Farm (Hendon). Inside these, most external work needs full planning and a Heritage Statement.
Getting around NW4: Hendon Central on the Northern line, plus Hendon Thameslink.
Regeneration: Hendon falls within or beside the West Hendon / Brent Cross regeneration nearby, which shapes local planning policy and design expectations.
Property values: the top quarter of last year's NW4 sales began at £850,000. For houses specifically, Barnet's semi-detached median was £815,000 from 954 sales and detached £1,250,000 from 329 — borough-wide numbers, because the price paid file does not break this district down by house type.
Borough character: Suburban outer-London borough; permitted development used heavily; Hampstead Garden Suburb has its own residents' trust with additional design controls.
Measured existing survey, photographic record, Article 4 and conservation check specific to Hendon before we quote.
2–3 design options at concept stage — alternative layouts, glazing, roof forms.
Site location plan, existing and proposed plans, elevations, sections, D&AS where required.
Part L thermal, Part B fire, Part M accessibility, structural strategy.
Steel beam, foundation, lintel design. Chartered engineer sign-off.
Party Wall notices where needed; Thames Water Build Over Agreement where within 3m of a public sewer.
Single planning or building-regs submission.
Planning + building regs + structural.
Listed, conservation or complex sites.
Because NW4 is a settled family suburb of inter-war semis and terraces around Hendon Central and Brent Street — ideal for rear and side extensions and hip-to-gable loft conversions. Outside the historic Burroughs conservation area, much of the work runs on the Permitted Development route, confirmed with a Lawful Development Certificate.
Yes — the Hendon Burroughs and Church Farm conservation areas protect the historic St Mary's core and the older houses, so external changes there need full planning with a Heritage Statement. We design sympathetically and handle the Barnet application where the conservation route applies.
Usually yes on the inter-war semis outside the conservation areas — a hip-to-gable plus rear dormer within the volume allowance, confirmed by a Lawful Development Certificate. We check the head height and any constraint, then draw the scheme for Building Control too.
With NW4 houses around £550,000-£900,000, a direct Northern line and the Brent Cross regeneration nearby, a rear extension or loft adds family space worth above the build and drawing cost. NW4 offers strong north-west London value.
Barnet Council charges its own statutory application fee (currently £548 for a householder planning application, £610 for a full application). We quote the drawings as one fixed price and the free site survey covers every NW4 address.
For a NW4 project across Hendon, Brent Street, Hendon Central, West Hendon fringe, expect roughly 3–4 weeks from instruction to submission: week 1 the measured survey, weeks 2–3 the drawings and your revisions, then validation and the statutory determination by Barnet Council (8 weeks for a householder application). We carry the Hendon application through every officer query to the decision.
Hendon (NW4) sits primarily in Barnet, so applications are decided by Barnet Council. Conservation areas within NW4 include Hendon Burroughs / St Mary's, Church Farm (Hendon), where full planning and a Heritage Statement are required. We confirm the planning route for your exact address before quoting.
Almost always. Any structural work behind house extension drawings in Hendon — new openings, steel beams, loft floors, foundations — needs Building Regulations approval covering structure (Part A), fire escape (Part B) and insulation (Part L), submitted to Barnet Council Building Control or an approved inspector. On NW4's typically terraced and semi-detached stock, a Party Wall notice to adjoining neighbours is normally required before the steelwork. We coordinate both as part of the Complete package.
In value terms, yes. The bigger risk is an unapproved or non-compliant scheme — which is why council-ready drawings and a clean Building Control sign-off matter on NW4 homes.
Moving, or weighing up a site in the next borough along? Here is the complete service list for N2, N3, N10, N12, N20, NW2, NW7 and NW11.
Pick a slot that suits you. No obligation and no sales pressure, just straight answers on your planning route.
Every NW4 postcode district we draw in, the stock that dominates it and the authority that validates a house extension there. NW4 fees below are the statutory England rates for 2026, not house extension estimates.
| Postcode | Area | Dominant stock | What it means for a house extension |
|---|---|---|---|
| NW4 | Hendon | 1930s semi-detached, post-war flats | A house extension at an NW4 address in Hendon is determined by Barnet Council under its own Local Plan policies for Hendon. |
| N2 | East Finchley | Edwardian terraces, 1930s semi-detached | Adjoining district to NW4, also inside Barnet for house extension purposes. |
| N3 | Finchley Central | 1930s semi-detached, Edwardian villas | Adjoining district to NW4, also inside Barnet for house extension purposes. |
| N11 | New Southgate / Bounds Green | mixed stock | Adjoining district to NW4, also inside Barnet for house extension purposes. |
| N12 | North Finchley / Woodside Park | 1930s semi-detached, Edwardian villas | Adjoining district to NW4, also inside Barnet for house extension purposes. |
Roof pitch, wall build-up and plot depth change every few NW4 streets, and each one changes what a house extension can achieve at that address.
NW4 (Hendon) conservation designations: there are 20 across Barnet Council, Mill Hill, Hendon, Golders Green among them. Designation costs a NW4 (Hendon) owner the permitted-development route: a house extension then needs a £548 householder application over 8 weeks, in place of the £249 prior approval route that takes 6 weeks. Monken Hadley is the NW4 (Hendon) designation that most often changes a house extension design.
No blanket Article 4 over NW4 (Hendon): Barnet Council has not withdrawn permitted development across NW4 (Hendon), so a house extension outside a NW4 (Hendon) conservation area usually keeps it. The £274 Lawful Development Certificate is still the document a NW4 owner wants on file.
The building fabric around NW4 (Hendon): 1930s semi-detached dominates; Edwardian villas in Muswell Hill, Finchley; Garden Suburb Arts & Crafts in Hampstead Garden Suburb; post-war flats in Colindale. Suburban outer-London borough; permitted development used heavily; Hampstead Garden Suburb has its own residents' trust with additional design controls. A house extension in NW4 (Hendon) is scoped against that stock first, because it decides whether the scheme runs as permitted development, a £274 Lawful Development Certificate, or a full £548 application to Barnet Council.
Sources for this NW4 house extension page: borough policies maps and conservation-area registers (2025–26), Royal Mail postcode district boundaries, the Town and Country Planning (Fees for Applications) (England) Regulations, the Town and Country Planning (General Permitted Development) (England) Order 2015 as amended, and the Party Wall etc. Act 1996.
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