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House extension plans in Northgate & West Green — a glazed single-storey rear extension on a period home
Northgate & West Green · House Extension Drawings & Planning

House extension plans in Northgate & West Green

Single-storey, double-storey, rear and side extension drawings for Northgate & West Green homes — measured to Crawley Borough Council's design guidance, delivered in days and revised free until your decision, with a free approval-odds check before you commit.

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Northgate & West Green householder planning by the numbers

Crawley Borough Council granted 82% of the householder planning decisions it made in its latest published year — 5 points below the 87% England-wide householder average. Northgate & West Green contains Dyers Almshouses Conservation Area, St. Peters Conservation Area, Sunnymead Conservation Area conservation areas (Dyers Almshouses Conservation Area designated 1996), so materials, fenestration and roof form are assessed against the appraisal, which is where a policy-literate drawing pack earns its keep. Its dominant postwar (1945–1970) housing stock sets the design brief on most streets.

Under Class B, a rear dormer stays permitted development up to 40m³ of added roof volume on a terrace or 50m³ on a semi-detached or detached house, while Class A allows a single-storey rear extension of 3m beyond the original rear wall on a terrace and 4m on a detached house before a full application is needed. Northgate & West Green carries at least one Article 4 direction, and conservation areas including Dyers Almshouses Conservation Area, St. Peters Conservation Area and Sunnymead Conservation Area remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Northgate & West Green is determined against an 8-week statutory target.

Dyers Almshouses (conservation area designated in 1996), St. Peters (conservation area designated in 2022) and Sunnymead (conservation area designated in 2004) — these are the Northgate & West Green pockets our drawings cover most. Heritage designations here include Dyers Almshouses Conservation Area, St. Peters Conservation Area and Sunnymead Conservation Area. Crawley Borough Council weighs each proposal against Crawley Borough Council's development plan and the design policies it applies to householder applications, where the 5,720 homes here are 37% 1945-1954, 7% 1955-1964, 7% 1983-1992, which is what sets the realistic roof and rear-projection options. On roofs the borough is simple gabled and hipped roofs typical of early postwar building and shallow gabled roofs typical of that period's building, over early postwar houses (37% of 5,720 homes), late-1950s and early-1960s houses (7%) and 1980s estate houses (7%).

What actually constrains a project in Northgate & West Green

Northgate & West Green's designated heritage is specific, and it is the first thing we check against your address: Dyers Almshouses (conservation area designated in 1996), St. Peters (conservation area designated in 2022) and Sunnymead (conservation area designated in 2004). Inside those boundaries permitted development is curtailed and Crawley Borough Council assesses materials, window detail and roof form against the area's own appraisal, so a scheme that would be waved through two streets away can need a full application here.

Crawley Borough Council has 19 recorded Article 4 directions, removing permitted development for painting the exterior — check the address before assuming PD applies in Northgate & West Green.

On stock, Northgate & West Green is early postwar houses (37% of 5,720 homes), late-1950s and early-1960s houses (7%) and 1980s estate houses (7%) — which is why simple gabled and hipped roofs typical of early postwar building and shallow gabled roofs typical of that period's building govern what a loft or rear projection can realistically be. Crawley Borough Council decided 122 householder applications in the latest published year and granted 82%, with 26% issued inside the eight-week target. Those are the numbers our drawings are prepared against.

The full build-period split for Northgate & West Green runs pre-1900 3% (170 homes), 1900-1918 3% (150 homes), 1919-1929 2% (100 homes), 1930-1939 5% (270 homes), 1945-1954 37% (2,100 homes), 1955-1964 7% (410 homes), 1965-1972 5% (270 homes), 1973-1982 3% (160 homes), 1983-1992 7% (410 homes), 1993-1999 6% (320 homes) and 2000-2008 7% (390 homes). That distribution is why pre-1900 detailing dominates the drawings here, and it is measured from council-tax records rather than assumed from the street name.

Crawley Borough Council also decides for Southgate and Three Bridges, so a decision in Northgate & West Green sits inside a wider pattern of decisions we track across the same authority — useful when an officer cites a precedent from the next area over.

The Article 4 directions recorded for this council include Aintree Road & Epsom Road, Arden Road, Ardingly Close and Beverley Mews. Each removes a specific permitted-development right inside its own boundary, which is why the check is done on the address rather than on the town.

Northgate & West Green in numbers — housing stock and planning decisions

Published figures for Northgate & West Green and Crawley Borough Council. These are the numbers that decide what is realistic on your street, so we work from them rather than from national averages.

MeasureNorthgate & West Green
Dwellings recorded5,720
Built pre-1900170 (3%)
Built 1900-1918150 (3%)
Built 1919-1929100 (2%)
Built 1930-1939270 (5%)
Built 1945-19542,100 (37%)
Built 1955-1964410 (7%)
Built 1965-1972270 (5%)
Built 1973-1982160 (3%)
Built 1983-1992410 (7%)
Built 1993-1999320 (6%)
Built 2000-2008390 (7%)
Built before 19196%
Built 1919–19396%
Built 1945–200871%
Conservation areas in Northgate & West Green3 (Dyers Almshouses Conservation Area, St. Peters Conservation Area…)
Conservation areas district-wide13
Article 4 directions recorded19
Householder applications decided122
Householder applications granted82%
Decided within 8 weeks26%

Dwelling stock from VOA council-tax data at 31 March 2025; conservation-area and Article 4 counts from planning.data.gov.uk (MHCLG); decision figures are Crawley Borough Council's own, from MHCLG live table PS2 for the year to 31 March 2026.

Extension plans built around Crawley Borough Council's rules

Northgate & West Green homes come in a handful of recurring shapes, and each one points to a different extension. The borough is built largely from early postwar houses (37% of 5,720 homes), late-1950s and early-1960s houses (7%) and 1980s estate houses (7%), so a Victorian terrace usually wants a rear or side-return infill, while an interwar semi has room for a wider single-storey wrap or a two-storey side addition. Crawley Borough Council judges every one of them against Crawley Borough Council's development plan and the design policies it applies to householder applications, weighing footprint, height and the impact on the house next door before it looks at the elevations.

That is why the drawings decide the outcome. We set the extension depth against the permitted-development limits precisely, keep the eaves and ridge within the allowances, and plot the 45-degree daylight lines to the neighbours' windows so the case officer can see the amenity test is passed. Northgate & West Green contains Dyers Almshouses Conservation Area, St. Peters Conservation Area, Sunnymead Conservation Area conservation areas (Dyers Almshouses Conservation Area designated 1996), so materials, fenestration and roof form are assessed against the appraisal, so we design around it from the first sketch rather than discover it at validation.

Northgate & West Green also protects whole streets — Dyers Almshouses Conservation Area, St. Peters Conservation Area and Sunnymead Conservation Area among them. Crawley Borough Council has 19 recorded Article 4 directions, removing permitted development for painting the exterior — check the address before assuming PD applies in Northgate & West Green. On designated land the larger-home extension route and most side extensions stop being permitted development, so we confirm your address against those layers before drawing a line.

Isometric house extension drawing for a Northgate & West Green home

Do I need planning permission to extend my house in Northgate & West Green?

Plenty of Northgate & West Green extensions are permitted development and need no planning application — a single-storey rear extension within the depth and height limits is the common case. You will normally need to apply to Crawley Borough Council if any of these apply:

  • The single-storey rear extension is deeper than 3 metres on a terrace or semi, or 4 metres on a detached house (6m/8m needs prior approval under the larger-home scheme)
  • It is a two-storey or double-storey extension, or the rear extension is higher than 4 metres
  • A side extension is wider than half the original house, or more than one storey
  • Any part projects forward of the principal (front) elevation, or the extension covers more than half the garden
  • Your home is in a conservation area such as Dyers Almshouses Conservation Area and St. Peters Conservation Area, where the larger-home route and side extensions are not permitted development
  • An Article 4 direction applies to your street — Northgate & West Green has several, so this is checked first

Northgate & West Green extension approval rates — live from council data

Below is Crawley Borough Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Crawley Borough Council granted 82% of its householder applications in the year to 31 March 2026, and Dyers Almshouses Conservation Area shapes what is approved here. A complete, policy-literate extension pack anticipates those pressure points before submission, which is why professionally drawn applications are decided faster and refused less often than DIY ones.

Source: MHCLG planning application statistics (householder decisions, England, 1 April 2025 - 31 March 2026). Compare every borough on our London approval-rate league table.

82%householder applications approved in Crawley
87%national average — Crawley is 5 points below the national average

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Which extensions get approved in Northgate & West Green

Across Dyers Almshouses, St. Peters and Sunnymead, the extension that lands most often is the single-storey rear addition — a glazed kitchen-diner across the back of the house, kept within the permitted-development depth or taken to a full application where the ground floor wants more. On the borough's early postwar houses (37% of 5,720 homes), a side-return infill frequently pairs with it to square off the plan; on wider 1980s estate houses (7%), a two-storey side or rear extension can add a bedroom above without swallowing the garden.

The 5,720 homes here are 37% 1945-1954, 7% 1955-1964, 7% 1983-1992, which is what sets the realistic roof and rear-projection options. We size the extension to the amenity and daylight tests, match the roof and materials to the host house, and keep enough garden to satisfy Crawley Borough Council's space standards — so the scheme answers the borough's questions before an objection can raise them. Where permitted-development rights are used up or removed, we prepare the householder application to the council's extension design guidance instead.

Single-storey rear extension opening onto the garden of a Northgate & West Green house

House extensions across Northgate & West Green

We draw extensions on every street in the borough. A few of the neighbourhoods where Northgate & West Green projects come up most often:

Dyers Almshouses

Extension drawings for Dyers Almshouses's conservation area designated in 1996 — footprint-checked, daylight-tested and drawn to Crawley Borough Council's guidance.

St. Peters

Extension drawings for St. Peters's conservation area designated in 2022 — footprint-checked, daylight-tested and drawn to Crawley Borough Council's guidance.

Sunnymead

Extension drawings for Sunnymead's conservation area designated in 2004 — footprint-checked, daylight-tested and drawn to Crawley Borough Council's guidance.

Which extension suits your Northgate & West Green home?

The right extension in Northgate & West Green depends on your house type and how much garden you can give up. This is how the main options compare on planning route and what they add.

Extension typePermitted development?What it addsWhat Crawley Borough Council checks
Single-storey rearOften, within 3m/4m depth (6m/8m via prior approval)Bigger kitchen-diner across the backDepth, height, neighbour daylight (45°)
Side-return infillSometimes, if within width and height limitsSquares off an L-shaped ground floorWidth vs the original house, glazing to boundary
Two-storey rear/sideNo — full applicationExtra bedroom or bathroom aboveBulk, overlooking, 7m rear-boundary gap
Wraparound (rear + side)No — full applicationWhole-width open-plan ground floorCombined footprint and garden retained

Route depends on your street — conservation areas such as Dyers Almshouses Conservation Area and St. Peters Conservation Area and Article 4 directions can remove permitted-development rights.

Four steps to an approved Northgate & West Green extension

A fixed process built around how Crawley Borough Council validates and decides householder extension applications — most drawings are submission-ready within seven days of survey.

  1. 1

    Free approval check

    Tell us your Northgate & West Green postcode and house type. We confirm your conservation and Article 4 status, how much permitted-development depth you have left, and score your odds against live Crawley Borough Council decisions.

  2. 2

    Measured survey

    We measure the existing footprint, floor and eaves levels, boundary distances and the neighbours' window positions — the numbers the depth limits and daylight tests depend on.

  3. 3

    Extension design & drawings

    Chartered designers develop the single-storey, two-storey or side extension to your brief, drawn inside the permitted-development limits or to Crawley Borough Council's extension design guidance.

  4. 4

    Submission & follow-through

    We submit the certificate, prior-approval notice or application, manage validation and case-officer queries, and revise the drawings free until Crawley Borough Council issues its decision.

Frequently asked questions

Do I need planning permission to extend my house in Northgate & West Green?

Not always. A single-storey rear extension up to 3 metres deep on a terrace or semi, or 4 metres on a detached house, and no higher than 4 metres, is usually permitted development. In Northgate & West Green you will need to apply to Crawley Borough Council for two-storey extensions, side extensions wider than half the house, anything forward of the front wall, deeper rear extensions under the larger-home prior-approval route, and any extension in a conservation area such as Dyers Almshouses Conservation Area and St. Peters Conservation Area.

How deep can a single-storey rear extension go in Northgate & West Green without planning permission?

Standard permitted development allows 3 metres on a terraced or semi-detached house and 4 metres on a detached one. The larger-home extension scheme can double that to 6 or 8 metres, but it needs a prior-approval notification to Crawley Borough Council and a neighbour-consultation period, and it does not apply on designated land such as Northgate & West Green's conservation areas. We confirm which route your property qualifies for before drawing.

Can I build a double-storey extension in Northgate & West Green?

Two-storey and double-storey extensions almost always need a full householder application to Crawley Borough Council, because they fall outside permitted development on most homes. The council looks closely at bulk, overlooking of neighbours and the 7-metre gap a two-storey rear extension must keep from the rear boundary. We design to those tests and show the daylight and privacy angles on the drawings. This applies to your Northgate & West Green address specifically.

How long does Crawley Borough Council take to decide an extension application?

A householder planning application in Northgate & West Green runs to a statutory eight-week target, a larger-home prior-approval notification to around six weeks including the neighbour-consultation period, and a lawful development certificate to eight weeks. Incomplete submissions stall at validation, so we submit a complete pack and manage officer queries to keep the decision on schedule. Crawley Borough Council is the decision-maker.

Will my extension in Northgate & West Green need building regulations approval as well as planning?

Yes — planning permission and building regulations are separate consents, and almost every extension needs both. Planning governs whether you can build it; building control governs how it is built, covering structure, insulation, drainage and fire safety. We prepare the building-regulations drawings alongside the planning set so Crawley Borough Council's building control or an approved inspector can sign the work off. This applies to your Northgate & West Green address specifically.

How much do extension plans in Northgate & West Green cost?

Every house and brief is different, so we price each Northgate & West Green extension individually and send a fixed, no-obligation quote back within one working day. It covers the full drawing pack with free revisions until Crawley Borough Council approves, and we tell you upfront whether your extension qualifies as permitted development. Call 020 7864 7245 to get started.

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