Back-of-house extension drawings for Westminster homes — the glazed kitchen-diner across the rear, drawn to Westminster City Council's depth and daylight limits, delivered in days and revised free until your decision, with a free approval-odds check first.
Westminster City Council granted 87% of the householder planning decisions it made in its latest published year — level with the 87% England-wide householder average. Basement excavation is tightly policed on depth, garden coverage and construction impact given the density of listed and stucco stock, which is where a policy-literate drawing pack earns its keep. Its dominant Georgian (1714–1837) and Victorian (1837–1901) housing stock sets the design brief on most streets.
The permitted-development ceilings are fixed: 40m³ of new roof volume for a terraced loft and 50m³ for a semi or detached house under Class B, plus a 3m single-storey rear extension on a terrace or 4m on a detached house under Class A. Westminster carries at least one Article 4 direction, and conservation areas including Bayswater, Maida Vale and Pimlico remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Westminster is determined against an 8-week statutory target.
Bayswater (stucco terraces around leafy garden squares), Maida Vale (red-brick and stucco mansion blocks along wide avenues), Pimlico (Thomas Cubitt's uniform white stucco terraces), Marylebone (Georgian and Victorian terraces mixed with mansion flats), Belgravia (grand stucco terraces served by their own mews) and Queen's Park (the model-cottage streets of the Queen's Park Estate on the Westminster side) — these are the Westminster pockets our drawings cover most. Heritage designations here include Bayswater, Maida Vale, Pimlico, Marylebone and Queen's Park. Westminster City Council weighs each proposal against the Westminster City Plan and the Basements SPD, where mansard and roof extensions are steered by the roof-extension policy to sit within an unbroken terrace profile. Larger stucco houses in Bayswater and Marylebone are widely converted into flats, which carry no householder permitted-development rights.. On roofs the borough is mansard roofs to the stucco terraces and concealed butterfly roofs behind parapets, over stucco-fronted Georgian and Victorian terraces, purpose-built mansion flats and mews houses to the rear of the grand streets.
The rear extension is the workhorse of Westminster home improvement — it is how a dark back kitchen becomes an open family room facing the garden. Because the borough is built largely from stucco-fronted Georgian and Victorian terraces, purpose-built mansion flats and mews houses to the rear of the grand streets, most back walls sit close to a neighbour on at least one side, and that proximity, not the design, is what Westminster City Council scrutinises. The council reads the proposal against the Westminster City Plan and the Basements SPD, and the first line an officer draws is the 45-degree splay from the neighbour's nearest window.
So the drawings live or die on geometry. We set the depth against the exact permitted-development figure, hold the eaves and the flat-roof or lantern build-up under the 4-metre height ceiling, and show the projection tested against both the 45-degree plan angle and the 25-degree section angle to the neighbouring windows. Basement excavation is tightly policed on depth, garden coverage and construction impact given the density of listed and stucco stock, so the rear elevation is composed around it rather than corrected after an objection.
Where the property sits in a conservation area — Bayswater, Maida Vale, Pimlico, Marylebone and Queen's Park among Westminster's — the larger-home extension route is switched off and even a modest rear addition needs consent. The overwhelming majority of Westminster lies within a conservation area, and Article 4 directions across districts like Bayswater and Pimlico remove permitted-development rights on facades, roofs and windows. We confirm the designation before the survey.
Many single-storey rear extensions in Westminster are permitted development and need no application. You will normally need to apply to Westminster City Council, or use the larger-home prior-approval route, if any of these apply:
We draw the depth, the roof build-up and the daylight splays to each neighbour on the page — the tests Westminster City Council's officers apply first — and submit a validation-complete pack, whether that is a lawful development certificate, a larger-home prior-approval notice or a full householder application.
Below is Westminster City Council's real householder decision record, taken from official planning statistics and refreshed as new data lands. Westminster grants a high share of householder applications, though near-total conservation-area coverage and a restrictive basement regime are the constraints behind most refusals. Rear extensions turn most often on neighbour daylight and depth, so a drawing pack that proves those tests upfront is decided faster and refused less often than a DIY submission.
Source: MHCLG planning application statistics (householder decisions, rolling year). Compare every borough on our London approval-rate league table.
Tell us about your project and get a fixed, no-obligation quote back within one working day. If you don't need planning permission at all, we'll tell you that too — for free.
Across Bayswater, Maida Vale and Pimlico, the approved rear extension is typically a single-storey glazed box within the depth limit, roofed either flat with a lantern or in a shallow mono-pitch, and finished in brick or render to match the host wall. On the borough's stucco-fronted georgian and victorian terraces, keeping the projection to the permitted-development figure often avoids an application entirely; where owners want the full 6 metres, the larger-home route succeeds when the neighbour-consultation period passes without a sustained objection.
Mansard and roof extensions are steered by the roof-extension policy to sit within an unbroken terrace profile. We keep the extension inside the daylight splays, set any glazed roof below the first-floor cill, and retain the garden depth Westminster City Council expects — so the back elevation answers the amenity case before a neighbour can lodge one. Two-storey rear extensions we draw with the 7-metre boundary gap and privacy screening resolved on the plan.
We draw rear extensions on every street in the borough. A few of the neighbourhoods where Westminster back-of-house projects come up most often:
Rear extension drawings for Bayswater's stucco terraces around leafy garden squares — depth-checked, daylight-tested and drawn to Westminster City Council's guidance.
Rear extension drawings for Maida Vale's red-brick and stucco mansion blocks along wide avenues — depth-checked, daylight-tested and drawn to Westminster City Council's guidance.
Rear extension drawings for Pimlico's Thomas Cubitt's uniform white stucco terraces — depth-checked, daylight-tested and drawn to Westminster City Council's guidance.
Rear extension drawings for Marylebone's Georgian and Victorian terraces mixed with mansion flats — depth-checked, daylight-tested and drawn to Westminster City Council's guidance.
Rear extension drawings for Belgravia's grand stucco terraces served by their own mews — depth-checked, daylight-tested and drawn to Westminster City Council's guidance.
Rear extension drawings for Queen's Park's the model-cottage streets of the Queen's Park Estate on the Westminster side — depth-checked, daylight-tested and drawn to Westminster City Council's guidance.
How far you can extend at the back in Westminster depends on your house type and the route you take. This is how the options compare.
| Route | Depth allowed | Consent needed | What Westminster City Council checks |
|---|---|---|---|
| Standard permitted development | 3m terrace/semi · 4m detached | Lawful development certificate (optional) | Depth, 4m height, materials |
| Larger-home prior approval | 6m terrace/semi · 8m detached | Prior-approval notice + neighbour consultation | Neighbour objections on amenity |
| Full householder application | Beyond the above, or two-storey | Full planning permission | Daylight (45°/25°), bulk, garden retained |
| Conservation area | Case by case | Full planning permission | Character, roof form, boundary treatment |
The larger-home route is switched off on designated land — conservation areas such as Bayswater and Maida Vale and Article 4 streets need a full application.
A fixed process built around how Westminster City Council validates and decides rear-extension applications — most drawings are submission-ready within seven days of survey.
Send us your Westminster postcode and house type. We confirm your conservation and Article 4 status, how much rear-extension depth you have under permitted development, and score your odds against live Westminster City Council decisions.
We measure the original rear wall, floor and eaves levels, side and rear boundary distances and the neighbours' window positions — the numbers the depth limit and daylight splays depend on.
Chartered designers develop the single or two-storey rear extension to your brief, drawn inside the permitted-development limits or to Westminster City Council's extension design guidance, with the daylight angles shown.
We submit the certificate, prior-approval notice or application, handle validation and case-officer queries, and revise the drawings free until Westminster City Council issues its decision.
Often not. 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 Westminster. You will need to involve Westminster City Council for anything deeper via the larger-home route, for two-storey rear extensions, and for any rear extension in a conservation area such as Bayswater and Maida Vale, where those permitted-development rights fall away.
The larger-home extension scheme lets a single-storey rear extension reach 6 metres on a terrace or semi, or 8 metres on a detached house — double the standard allowance. It is not automatic: you submit a prior-approval notification to Westminster City Council, neighbours are consulted, and if one objects on amenity grounds the council rules on it. It also does not apply on designated land such as Westminster's conservation areas.
It is the daylight test Westminster City Council applies to protect neighbours. Drawn on plan, a line at 45 degrees from the midpoint of the neighbour's nearest ground-floor window should not be crossed by your extension; a companion 25-degree line is checked in section. If the projection breaches it, the extension is likely to be shortened or refused, so we test and prove it on the drawings before submission.
A two-storey rear extension almost always needs a full householder application to Westminster City Council, as it sits outside permitted development on most homes. The council checks that it stays at least 7 metres from the rear boundary, does not overbear the neighbours and avoids new overlooking. We resolve the boundary gap, privacy and daylight on the plans so the application is decided on its merits.
Frequently, yes. If the rear extension involves work to a shared wall, building up to the boundary, or excavating foundations near a neighbour's structure, the Party Wall etc. Act applies and you must serve notice — this is separate from Westminster City Council's planning decision. We flag it early and can prepare the drawings a party-wall surveyor needs alongside the planning set.
We price each Westminster rear extension on its own footprint and send a fixed, no-obligation quote within one working day. It covers the full drawing pack with free revisions until Westminster City Council approves, and we confirm at the outset whether your extension is permitted development, needs prior approval, or a full application. Call 020 7864 7245 to begin.
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Same fixed quotes, same fast drawings — wherever your project is.