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Free 2026 London Planning ReportHouse Extension Drawings in Hampstead NW3

Basement conversion drawings for a Victorian villa in Hampstead NW3, London Borough of Camden
Hampstead · NW3 · Camden

House Extension Drawings in Hampstead NW3

Fixed-fee, MCIAT-chartered house extension drawings for Hampstead (NW3) homeowners — London Borough of Camden validation and local constraints handled from the start.

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Hampstead (NW3) is, in permitted-development terms, close to a special case. Three conservation areas cover the district — Hampstead, Belsize and Fitzjohns/Netherhall — and Camden has attached a non-immediate Article 4 direction to each of them, on top of the borough-wide Basements direction. The practical effect is that very little in NW3 proceeds under permitted development.

That reshapes what a project looks like here. Basement works need a full application under the Basements direction; the non-immediate Article 4 directions across Hampstead (excluding Frognal Way), Belsize and Fitzjohns/Netherhall strip further rights inside those conservation areas; the village core carries a very high concentration of listed buildings needing listed building consent alongside planning; and because so many of the large Fitzjohns Avenue and Belsize Park villas were long ago converted into flats, a large share of NW3 work is flat alteration — where permitted development rights do not exist in the first place. We establish the designation, listing and tenure position for an NW3 address before drawing to Camden's guidance.

Basement conversion drawings for a Victorian villa in Hampstead NW3, London Borough of Camden
Isometric illustration of a Hampstead NW3 home house extension drawings design
Proposed floor plan
Hampstead NW3

Planning in Hampstead (NW3): what to know before you apply

NW3 is one of the most heavily restricted districts in London for householder work. Camden's Basements Article 4 direction removes permitted development rights for basement schemes, and non-immediate Article 4 directions apply across all three conservation areas — Hampstead (excluding Frognal Way), Belsize and Fitzjohns/Netherhall — removing further rights inside them. The village core has a very high concentration of listed buildings requiring listed building consent, and the widespread conversion of the large villas into flats means many NW3 projects have no permitted development rights regardless of designation. Assume a full application in NW3.

Typical Hampstead housing stock

Georgian houses in the old village core, substantial Victorian red-brick villas along Fitzjohns Avenue and Netherhall Gardens, and large Victorian semi-detached and terraced houses through Belsize Park, much of it converted to flats.

Streets we regularly draw for in Hampstead

Hampstead High Street · Fitzjohns Avenue · Netherhall Gardens · Belsize Park Gardens

What NW3 is actually built of

Measured from 237 classified residential buildings in NW3, not from a description of the area.

Hampstead NW3 housing mix

Residential building form across the NW3 postcode district, from 237 classified buildings.

Attached on more than one side43%
Attached on one side37%
Detached20%
Median building footprint92 m²
Addresses per buildingAbove about 2 means flats and maisonettes dominate2.82
Buildings classified237

Source: Ordnance Survey National Geographic Database (derived statistics). Contains OS data © Crown copyright and database right 2026. Contains Royal Mail data © Royal Mail copyright and database right 2026. Extracted 2026-08-17.

House Extension Drawings for Hampstead (NW3) homes: the package and the process

Extension drawings are read for their dimensions. The proposed plan needs depth measured from the original rear wall — not from a previous extension — eaves and ridge heights taken from existing ground level, and the distance to each boundary marked. A site plan showing how much garden remains is what an officer reaches for when the amenity question comes up.

We draw the existing building accurately first, because everything else is measured from it. Where the original footprint has already been added to, that history goes on the drawing: it decides which allowances are still available and it is the first thing an officer checks against the council's own records.

The plot decides the extension type long before taste does. A mid-terrace has depth to work with and an alley if it is lucky; a semi has one clear flank; a detached house can go wide. Reading the building form first is what stops a design being drawn that the plot cannot take.

Which extension types do you draw?

Every London extension is shaped by the plot, the neighbours and the borough's design guidance. We draw them all.

Rear extension

A single-storey rear extension is often permitted development within depth limits — ideal for an open-plan kitchen-diner.

Side-return

Fills the alley beside a Victorian terrace, widening the ground floor without losing garden.

Wraparound

Combines a rear and side-return extension for a transformative ground floor, usually needing planning permission.

Double-storey

Adds space above and below, subject to tighter scale and neighbour-impact scrutiny.

Basement

Creates space downward where footprint is limited, with structural and party-wall care.

Do I need planning permission for a house extension in London?

Single-storey rear extensions within permitted development limits (up to 6m for terraced/semi-detached homes under the larger-home scheme, subject to neighbour consultation) may not need a full application. Wraparounds, double-storeys and anything in a conservation area usually do. We assess your plot and recommend the right route before drawing. The current depth, height and eaves limits are set out in full in the guide to planning permission for a rear extension, and where you would rather one practice ran the design, the application and the building-regulations stage together, Architectural Drawings covers that full scope.

How do you maximise the footprint the council will approve?

We know each borough's depth, height and daylight standards, so we design to the edge of what will be approved rather than guessing — and we check the 45-degree neighbour daylight rule and any rear building line before submission. Where a plot is tight we test a permitted-development scheme against a slightly larger householder application and show you the trade-off in space, cost and timescale, so the drawn scheme is the one that actually maximises value rather than just floor area.

Typical London extension drawing packages
ExtensionTypical routePackageFee from
Single-storey rearPermitted development / householderPlanning + building regs£1,100
Side-returnHouseholder planningPlanning + building regs + structural£1,600
WraparoundHouseholder planningFull package + structural£2,200
Double-storeyHouseholder planningFull package + structural£2,400
Sheet from a house extension drawings package drawn for a Hampstead property in NW3, showing the existing and proposed arrangement at scale
A sheet from the house extension drawings package we submit to London Borough of Camden for Hampstead (NW3) properties.
FAQ

House Extension Drawings in Hampstead NW3 — FAQs

How far can I extend without planning permission in London?+
Under permitted development, single-storey rear extensions can reach 3m (terraced/semi) or 4m (detached), or up to 6–8m under the prior-approval larger-home scheme — but conservation areas and Article 4 directions can remove these rights. We check your property first.
Do extension drawings include structural calculations?+
Our full package includes structural drawings and calculations coordinated in-house, so your builder can price and build without waiting on an engineer.
How long do extension drawings take?+
Typically about 7 days from survey to a full drawing set delivered to your online portal.
Will my rear extension need a party wall agreement?+
If you build up to or on a shared boundary, excavate near a neighbour's foundations, or cut into a party wall for a steel, the Party Wall etc. Act 1996 usually applies. Our drawings show the works clearly so a party wall surveyor — or your neighbour — can see exactly what is proposed, which keeps that process quick.
Can I extend a house in a conservation area?+
Yes, but conservation areas and Article 4 directions commonly remove permitted development for rear and side extensions, so the work needs a full householder application designed to the council's heritage guidance. We confirm your property's designation before recommending a route.
Do I need planning permission for a rear extension in Camden?+
Frequently, yes. Much of Camden sits within a conservation area or is listed, and near-borough-wide conservation coverage removes permitted development for many external works. On unlisted homes outside a conservation area a rear extension may still qualify, but in Hampstead, Belsize Park and Primrose Hill a full application is usually needed. We confirm the exact constraints for your address before drawing.
What is a Basement Impact Assessment and will I need one in Camden?+
Camden operates one of the most rigorous basement policies in London. Schemes involving a basement or lower-ground extension generally require a Basement Impact Assessment addressing structural stability, drainage and groundwater. If you are considering below-ground space we flag the requirement early and coordinate the assessment so the application is complete when it is submitted.
Can I make changes to a listed building in Camden?+
Often, but listed-building consent is usually required alongside — or instead of — planning permission, and internal as well as external changes can be controlled. Camden has a high density of listed buildings in Hampstead, Bloomsbury and Fitzrovia. We screen listing status for your address first and prepare the heritage-led drawings and justification the council expects.
How long does Camden take to decide an application?+
Camden determines most householder applications within the statutory eight-week period once validated; basement, conservation and listed-building cases can involve additional consultation. We prepare Camden submissions to the council's validation and design standards to avoid the drawing queries that cause most delays.
How much do planning drawings cost in Camden?+
We agree a fixed fee before we start, typically around 30% below an architect's fee for the same council-accepted drawings, with free redraws until Camden approves. A conservation-area rear extension, a basement and a listed-building scheme differ in the evidence required, so we quote once we have seen your project rather than by the hour.
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