Dormer, hip-to-gable and mansard loft conversion drawings for Westminster homes — prepared to Westminster City Council's design guidance, delivered in days and revised free until your decision lands, with a free approval-odds score 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.
Westminster's roofs set the brief. 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, and its lofts sit under mansard roofs to the stucco terraces and concealed butterfly roofs behind parapets — the geometry that decides whether a rear dormer, a hip-to-gable or a mansard gives you the headroom you want. Westminster City Council assesses loft proposals against the Westminster City Plan and the Basements SPD, and its case officers read each roof against the pair next door and the wider street before they read the plans.
That makes drawing quality decisive. We measure ridge and eaves heights, roof pitch and the existing stair, calculate the added volume against the permitted-development limits exactly, and show the workings on the drawings so Westminster City Council can verify them. Basement excavation is tightly policed on depth, garden coverage and construction impact given the density of listed and stucco stock, so we resolve it on the page rather than leave it for the case officer to raise.
Westminster also carries protected 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. We check your address against those designations before a line is drawn.
Many Westminster loft conversions proceed without planning permission — a rear dormer within the permitted-development volume limits (40 cubic metres on a terrace, 50 on a semi or detached house) is usually lawful. You will normally need a full application to Westminster City Council if any of these apply:
We draw the roof line, the ridge height and the neighbour's daylight on the page — the relationships Westminster City Council's officers check first — and submit a validation-complete pack, whether that is a lawful development certificate or a full householder application.
Below is Westminster City Council's real householder decision record, pulled from official planning statistics and updated 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. Professionally prepared loft drawings anticipate those pressure points before submission, which is why complete, policy-literate packs are decided faster and refused less often than DIY applications.
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 recurring loft is the rear dormer — a box across the back roof slope that turns a cramped attic into a full-height double bedroom and en-suite. On mansard roofs to the stucco terraces, that is usually the most efficient use of the roof; where the stock is concealed butterfly roofs behind parapets, a hip-to-gable followed by a rear dormer unlocks far more space, though it needs a full application.
Mansard and roof extensions are steered by the roof-extension policy to sit within an unbroken terrace profile. We draw the dormer inside the volume allowance, keep the flat-roof build-up below the ridge, and set the face back from the eaves as the rules require — so the pack answers Westminster City Council's questions before they are asked. Where permitted-development rights are exhausted or removed, we prepare a householder application composed to the borough's roof-alteration guidance instead.
We draw loft conversions on every street in the borough. A few of the neighbourhoods where Westminster roofs come up most often:
Loft conversion drawings for Bayswater's stucco terraces around leafy garden squares — measured, volume-checked and drawn to Westminster City Council's guidance.
Loft conversion drawings for Maida Vale's red-brick and stucco mansion blocks along wide avenues — measured, volume-checked and drawn to Westminster City Council's guidance.
Loft conversion drawings for Pimlico's Thomas Cubitt's uniform white stucco terraces — measured, volume-checked and drawn to Westminster City Council's guidance.
Loft conversion drawings for Marylebone's Georgian and Victorian terraces mixed with mansion flats — measured, volume-checked and drawn to Westminster City Council's guidance.
Loft conversion drawings for Belgravia's grand stucco terraces served by their own mews — measured, volume-checked and drawn to Westminster City Council's guidance.
Loft conversion drawings for Queen's Park's the model-cottage streets of the Queen's Park Estate on the Westminster side — measured, volume-checked and drawn to Westminster City Council's guidance.
The right loft in Westminster depends on your roof. This is how the main types compare on planning route and the space they add.
| Loft type | Permitted development? | Space & headroom | What Westminster City Council checks |
|---|---|---|---|
| Rear dormer | Usually yes, within volume limits | Full-height double room at the back | Volume, set-back from eaves, ridge height |
| Hip-to-gable | No — full application | Extends the whole side of the roof | Roof bulk and the symmetry of the pair |
| Mansard | No — full application | Maximum floor area across the roof | Street character, especially in conservation areas |
| Rooflights only | Usually yes (Class C) | Light and headroom, no extra footprint | Whether rooflights sit within the existing slope |
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 loft applications — most drawings are submission-ready within seven days of survey.
Tell us your Westminster postcode and roof type. We confirm your conservation and Article 4 status, how much permitted-development volume you have left, and score your odds against live Westminster City Council decisions.
We measure ridge and eaves heights, roof pitch, joist levels and the existing stair — the numbers the volume calculation and head heights depend on.
Chartered designers develop the dormer, hip-to-gable or mansard to your brief, drawn inside the Class B limits or to Westminster City Council's roof-alteration guidance.
We submit the certificate or application, manage validation and case-officer queries, and revise the drawings free until Westminster City Council issues its decision.
Often not. A rear dormer within 40 cubic metres on a terrace, or 50 on a semi-detached or detached house, set back from the eaves and no higher than the ridge, is usually permitted development. In Westminster the main exceptions are hip-to-gable conversions, dormers visible from the highway, and homes in conservation areas such as Bayswater and Maida Vale or on streets with an Article 4 direction. Westminster City Council is the decision-maker.
Generally no. In conservation areas including Bayswater and Maida Vale, Class B permitted-development rights for lofts are removed, so a rear dormer that would be lawful elsewhere needs a full application to Westminster City Council. 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 check your exact address before drawing.
On mansard roofs to the stucco terraces, common across Westminster, a rear dormer is usually the most efficient conversion and often permitted development. Where the roof is concealed butterfly roofs behind parapets, a hip-to-gable followed by a rear dormer gains far more usable space but needs planning permission. Our survey confirms which your roof supports before we draw. Westminster City Council is the decision-maker.
A householder planning application in Westminster runs to a statutory eight-week target, and a lawful development certificate to eight weeks as well, though validation can add time if the pack is incomplete. We submit validation-complete drawings and manage case-officer queries to keep the decision on track. Westminster City Council is the decision-maker.
If your dormer is permitted development, a lawful development certificate from Westminster City Council is council-stamped proof of that — worth having, because every buyer's solicitor will ask for it when you sell. We prepare and submit the certificate application with the same drawing pack.
Every roof is different, so we quote each Westminster project individually — a fixed, no-obligation price back within one working day. The quote covers the full drawing pack with free revisions until Westminster City Council approves, and we tell you upfront whether your loft qualifies as permitted development. Call 020 7864 7245 to start.
Answer five quick questions and get a free planning score for your exact address — instantly. Then, if you want the full picture, unlock the detailed analysis: your council's live approval rates, local precedents, constraints on your street and a step-by-step route to permission.
Same fixed quotes, same fast drawings — wherever your project is.