The whole spectrum — rear extensions, side returns, wraparounds, double-storey, basement digs. Planning-led design with detailed technical phase, ideal for edwardian villas in Queen's Park and Mapesbury typical of Brent.
On the 6m route, more refusals than grants: 27 prior approvals granted against 249 refused, with 518 ruled not required. Brent approved 78.5% of householder applications overall and issued 399 enforcement notices, more than any other London borough.
| Measure | Brent | London |
|---|---|---|
| Larger-extension notifications | 794 | 518 not required, 27 granted, 249 refused |
| Householder approval rate | 78.5% | 83.0% |
| Enforcement notices issued | 399 | highest of the 33 |
| Extension applications in the Datahub | 12,772 | 69% approved |
| Article 4 areas in the register | 162 | fourth most of the 16 boroughs in the Article 4 register |
| Lawful development certificates issued | 1,367 | — |
Sources: decision and enforcement figures from MHCLG District Planning Application Statistics (PS1 and PS2), twelve quarters to March 2026; the Datahub row from the Planning London Datahub, retrieved 15 August 2026, comparable within Brent only; the Article 4 register from the MHCLG Planning Data Platform, retrieved 1 September 2026. A 'not required' ruling means the extension may be built as notified.
In Brent — Edwardian villas in Queen's Park and Mapesbury; Victorian terraces in Kilburn and Harlesden; 1930s semi-detached in Wembley; post-war tower blocks in Church End for the most part — a house extension drawings package is the full measured-survey-to-submission drawing set London Borough of Brent needs in order to determine an application: existing and proposed plans, elevations and sections at 1:100 and 1:50, a location and site plan, and the supporting statements the case officer asks for.
Prepared and reviewed by the architectural technologist team at Architectural Drawings London — CIAT Affiliate, professional indemnity insured.Last reviewed 2026-08-03.
The whole spectrum — rear extensions, side returns, wraparounds, double-storey, basement digs. Planning-led design with detailed technical phase, ideal for edwardian villas in Queen's Park and Mapesbury typical of Brent.
Housing stock in Brent: Edwardian villas in Queen's Park and Mapesbury; Victorian terraces in Kilburn and Harlesden; 1930s semi-detached in Wembley; post-war tower blocks in Church End.
Character: Highly diverse borough; Queen's Park and Mapesbury are heritage-controlled; Wembley is a major regeneration hub.
Article 4: the Article 4 directions here target conversion to multiple occupancy on named streets around Wembley and Harlesden rather than blanketing the borough, so the answer depends on your road.
A laser survey of the existing house, a photographic record of its present condition, and a check of that exact address against Brent's Article 4 and conservation boundaries. All of it happens before we quote a fee rather than after you have paid one.
Two or three genuine options at concept stage, not one scheme with the colours changed: different internal layouts, different glazing strategies, different roof forms, set against each other before anything is committed to.
Location plan, a floor plan of the house now and one of the house proposed, an elevation for every face that changes, sections through the new work, and a design and access statement on any scheme where Brent's validation list calls for one.
Steel beam, foundation, lintel design. Chartered engineer sign-off.
Party wall notices wherever the work is notifiable, and a Thames Water build-over agreement wherever the extension lands within three metres of a public sewer. Both are inexpensive to arrange in advance and costly to discover halfway through a dig.
Single planning or regs submission.
Planning + building regs + structural.
Listed, conservation, complex sites.
Move the controls for an indicative figure. It anchors your budget — it is not a quote. Every project is priced after a site survey.
Build costs are separate and quoted by your contractor. See our published fees.
Each Brent postcode district on our books, what was built there, and the authority that validates an extension in it. Every charge listed is a 2026 statutory application fee for England, and not one of them is a build cost.
| Postcode | Area | Dominant stock | What it means for a house extension |
|---|---|---|---|
| NW2 | Cricklewood / Neasden | Edwardian villas and terraces | NW2 divides Cricklewood and Neasden three ways, between Brent, Barnet and Camden. Three authorities means three sets of local policy sitting under one postcode, and a scheme drawn to satisfy one of them can be rejected at validation by another. |
| NW10 | Willesden / Harlesden / Kensal Green | Modern apartments, post-war estates | NW10 runs through Willesden, Harlesden and Kensal Green with the Ealing border cutting across it. Harlesden additionally carries Article 4 restrictions on conversion, so both questions, which council decides and which rights survive, need answering here before any design work starts. |
| HA0 | Wembley / Sudbury | 1930s semi-detached, new-build | HA0 covers Wembley / Sudbury only; Brent Council handles the house extension. |
| HA9 | Wembley / Wembley Park | 1930s semi-detached, new-build | HA9 is Wembley and Wembley Park, wholly inside Brent. It has absorbed most of the borough's recent building, and 17.0% of all Brent dwellings were completed after 2010. On the newer estates a management company's covenants can block an extension that planning policy would have allowed. |
| NW6 | Kilburn / West Hampstead / Queen's Park | Mansion blocks, post-war flats | NW6 spans Kilburn, West Hampstead and Queen's Park across the Camden and Brent boundary. Two councils apply two designation maps to what reads on the ground as one continuous run of terraces, so the road settles which validation list an extension is drawn to. |
| NW9 | Colindale / Kingsbury | Post-war flats, new-build | NW9 splits Colindale and Kingsbury between Barnet and Brent. The Kingsbury inter-war semis take a rear extension comfortably. The Colindale side is dominated by recent flats, where permitted development rights do not exist at all and every alteration is an application. |
Pitch, wall construction and the depth of ground behind the house vary within a single Brent street, and each of them sets a ceiling on what an extension can achieve at one particular address.
How designation changes a Brent house extension: Brent Council maintains 22 conservation areas, including Mapesbury, Kensal Green, Harlesden. Inside any of them a Brent house extension cannot rely on permitted development, and the route becomes a £548 householder application determined in 8 weeks rather than a £249 prior approval in 6 weeks. Harlesden sets the tone for Brent casework.
Brent and Article 4: Article 4 for HMO conversions in specific streets around Wembley and Harlesden. A house extension planned at a NW2 address is checked against that direction first; Brent Council publishes the Brent extent, and the NW2 line rarely follows the Brent boundary you would expect.
The building fabric around Brent: Edwardian villas in Queen's Park and Mapesbury; Victorian terraces in Kilburn and Harlesden; 1930s semi-detached in Wembley; post-war tower blocks in Church End. Highly diverse borough; Queen's Park and Mapesbury are heritage-controlled; Wembley is a major regeneration hub. A house extension in Brent 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 Brent Council.
Sources for this Brent 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.
What Brent owners genuinely ask us about extension drawings, answered from the borough's own recorded numbers instead of from general guidance.
Start a free quote →Most extensions in Brent stay inside permitted development, at three metres to the rear of an attached house or four metres behind a detached one, while a side addition is capped at one half of the width the house had when it was first built. Article 4 directions strip those rights from certain named streets in the borough. Flats are excluded outright, and so are listed buildings and anything within a designated boundary. We test eligibility against the address before quoting.
The baseline allowance runs to a single-storey rear projection of three metres where the house is attached and four where it is detached, all of it permitted development. Prior approval doubles those to 6m and 8m. Brent is not generous on that second route: of 794 larger householder applications determined across the three years ending March 2026, it refused 249, a 31.4% refusal share where the 33 boroughs pooled sit at 24.9%. Flats, listed buildings and Article 4 streets fall outside the whole scheme.
Brent's median sale price went backwards last year. It fell 1.8%, from £560,000 in 2024 to £550,000 in 2025 across 2,057 registered transactions, with a quarter of those sales completing below £408,900 (HM Land Registry, Price Paid dataset, retrieved 1 September 2026). That bears directly on an extension budget, because a softening median narrows the margin between what a scheme costs and what it returns, and it makes the difference between the two cost lines matter more. Ours is fixed: planning drawings, building regulations and the structural calculations, all inside one figure agreed at instruction. The builder's is priced by the square metre and moves with access, ground conditions and specification; a side return works out cheaper per square metre than a double-storey rear.
Beyond what the national framework already requires, Brent has adopted no basement policy at all, so a basement conversion here is weighed on structural design, on drainage and on flood risk, with no bespoke local test to satisfy. Flood Zone 3 covers 2.96% of the borough, so at most addresses the flood question resolves quickly. The item that more often holds up a Brent basement is the Thames Water build-over agreement.
Most Victorian terraces in Brent (particularly in Queen's Park) benefit from both — a side return extension infills the narrow side passage to create a wider kitchen, a rear extension projects back into the garden. A wraparound combines the two. We recommend the best option at the free site visit.
Brent's edwardian villas in Queen's Park and Mapesbury terraced and semi-detached stock typically suits rear single-storey extensions (kitchen-diners), side-return infill extensions, or double-storey rear. Wraparound extensions combine both directions for maximum gain. We recommend the most viable option at the free site visit.
We cover all Brent postcodes — NW2, NW6, NW9, NW10, HA0, HA9 — with local surveyors. Survey appointments within 3 working days.
Applications here are read against the London Plan and against Brent's own adopted policies together. Three things settle most householder cases: whether the materials match or deliberately complement what already stands, whether the neighbour keeps their daylight and outlook, and whether the new fabric satisfies Part L. Where a site's planning history is contested we include a summary of pre-application advice, because an officer who can see the history has been addressed reads the rest of the application differently.
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