Single-storey, double-storey, rear and side extension drawings for Westminster homes — measured to Westminster City Council's design guidance, delivered in days and revised free until your decision, with a free approval-odds check before you commit.
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.
Westminster homes come in a handful of recurring shapes, and each one points to a different extension. 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, 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. Westminster City Council judges every one of them against the Westminster City Plan and the Basements SPD, 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. Basement excavation is tightly policed on depth, garden coverage and construction impact given the density of listed and stucco stock, so we design around it from the first sketch rather than discover it at validation.
Westminster also protects whole streets — Bayswater, Maida Vale, Pimlico, Marylebone and Queen's Park among them. 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. 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.
Plenty of Westminster 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 Westminster City Council if any of these apply:
We draw the footprint, the ridge and eaves heights and the neighbours' daylight on the page — the relationships Westminster City Council's officers weigh first — and submit a validation-complete pack, whether that is a lawful development certificate, a prior-approval notification or a full householder application.
Below is Westminster City Council's real householder decision record, drawn 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. 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, 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 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 stucco-fronted georgian and victorian terraces, a side-return infill frequently pairs with it to square off the plan; on wider mews houses to the rear of the grand streets, a two-storey side or rear extension can add a bedroom above without swallowing the garden.
Mansard and roof extensions are steered by the roof-extension policy to sit within an unbroken terrace profile. 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 Westminster City 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.
We draw extensions on every street in the borough. A few of the neighbourhoods where Westminster projects come up most often:
Extension drawings for Bayswater's stucco terraces around leafy garden squares — footprint-checked, daylight-tested and drawn to Westminster City Council's guidance.
Extension drawings for Maida Vale's red-brick and stucco mansion blocks along wide avenues — footprint-checked, daylight-tested and drawn to Westminster City Council's guidance.
Extension drawings for Pimlico's Thomas Cubitt's uniform white stucco terraces — footprint-checked, daylight-tested and drawn to Westminster City Council's guidance.
Extension drawings for Marylebone's Georgian and Victorian terraces mixed with mansion flats — footprint-checked, daylight-tested and drawn to Westminster City Council's guidance.
Extension drawings for Belgravia's grand stucco terraces served by their own mews — footprint-checked, daylight-tested and drawn to Westminster City Council's guidance.
Extension drawings for Queen's Park's the model-cottage streets of the Queen's Park Estate on the Westminster side — footprint-checked, daylight-tested and drawn to Westminster City Council's guidance.
The right extension in Westminster 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 type | Permitted development? | What it adds | What Westminster City Council checks |
|---|---|---|---|
| Single-storey rear | Often, within 3m/4m depth (6m/8m via prior approval) | Bigger kitchen-diner across the back | Depth, height, neighbour daylight (45°) |
| Side-return infill | Sometimes, if within width and height limits | Squares off an L-shaped ground floor | Width vs the original house, glazing to boundary |
| Two-storey rear/side | No — full application | Extra bedroom or bathroom above | Bulk, overlooking, 7m rear-boundary gap |
| Wraparound (rear + side) | No — full application | Whole-width open-plan ground floor | Combined footprint and garden retained |
Route depends on your street — conservation areas such as Bayswater and Maida Vale and Article 4 directions can remove permitted-development rights.
A fixed process built around how Westminster City Council validates and decides householder extension applications — most drawings are submission-ready within seven days of survey.
Tell us your Westminster 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 Westminster City Council decisions.
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.
Chartered designers develop the single-storey, two-storey or side extension to your brief, drawn inside the permitted-development limits or to Westminster City Council's extension design guidance.
We submit the certificate, prior-approval notice or application, manage validation and case-officer queries, and revise the drawings free until Westminster City Council issues its decision.
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 Westminster you will need to apply to Westminster City 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 Bayswater and Maida Vale.
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 Westminster City Council and a neighbour-consultation period, and it does not apply on designated land such as Westminster's conservation areas. We confirm which route your property qualifies for before drawing.
Two-storey and double-storey extensions almost always need a full householder application to Westminster City 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.
A householder planning application in Westminster 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. Westminster City Council is the decision-maker.
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 Westminster City Council's building control or an approved inspector can sign the work off.
Every house and brief is different, so we price each Westminster extension individually and send a fixed, no-obligation quote back within one working day. It covers the full drawing pack with free revisions until Westminster City 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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Same fixed quotes, same fast drawings — wherever your project is.