The fast route to a deep single-storey rear extension in Kensington and Chelsea — up to 6 metres on an attached house or 8 on a detached one — via the Royal Borough of Kensington and Chelsea's prior approval scheme rather than a full planning application.
the Royal Borough of Kensington and Chelsea granted 85% of the householder planning decisions it made in its latest published year — 2 points below the 87% England-wide householder average. The borough runs the strictest basement policy in London — broadly one storey deep, under no more than half the garden, with a construction traffic management plan, 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.
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. Kensington and Chelsea carries at least one Article 4 direction, and conservation areas including Chelsea, Kensington and Holland Park remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Kensington and Chelsea is determined against an 8-week statutory target.
Chelsea (stucco terraces and mews streets off the King's Road), Kensington (grand stucco terraces and mansion blocks), Notting Hill (the Ladbroke Estate's stucco terraces around communal garden squares), Holland Park (large detached villas and substantial mansion flats), Knightsbridge (red-brick mansion blocks and stucco terraces) and Earls Court (tall Victorian terraces widely subdivided into flats) — these are the Kensington and Chelsea pockets our drawings cover most. Heritage designations here include Chelsea, Kensington, Holland Park, Ladbroke and Brompton. the Royal Borough of Kensington and Chelsea weighs each proposal against the RBKC Consolidated Local Plan and the Basements SPD, where with the roofscape closely protected, mansard and roof additions are judged against the prevailing profile of each terrace group. Subdivided period houses are common around Earls Court and Notting Hill, and converted flats hold no householder permitted-development rights.. On roofs the borough is concealed butterfly roofs behind the terrace parapets and mansard roofs added to the stucco terraces, over stucco-fronted Georgian and Victorian terraces, purpose-built mansion blocks and mews houses behind the main streets.
The ordinary Class A limits stop a single-storey rear extension at 3 metres on an attached house and 4 on a detached one. The larger home extension scheme doubles both, on condition that the council is told first. That notification is not an application for permission — the council cannot refuse on design, materials or policy grounds. It can only consider the effect on the amenity of adjoining premises, and only if a neighbour actually objects during the 21-day consultation.
The other conditions still apply and are strict: single storey only, no higher than 4 metres, eaves no higher than the existing eaves, and no more than half the land around the original house covered. It is not available on designated land, so a house in a conservation area such as Chelsea and Kensington cannot use it at all. Materials must be similar to the existing house, and the extension must not include a veranda, balcony or raised platform.
Kensington and Chelsea is largely stucco-fronted Georgian and Victorian terraces, purpose-built mansion blocks and mews houses behind the main streets. The borough runs the strictest basement policy in London — broadly one storey deep, under no more than half the garden, with a construction traffic management plan, which matters here because an objecting neighbour puts amenity squarely in front of a case officer. Almost the entire borough falls within a conservation area, and Article 4 directions strip out permitted-development rights so even minor external changes on the Ladbroke or Chelsea streets need consent.
The scheme is available where all of these hold. Fail any one and it is a full application to the Royal Borough of Kensington and Chelsea instead:
We prepare the notification pack the Royal Borough of Kensington and Chelsea needs — plans, elevations, a site plan with the adjoining owners identified — and manage the 21-day neighbour consultation so the 42-day clock is not restarted by an incomplete submission.
Below is the Royal Borough of Kensington and Chelsea's real householder decision record, drawn from official planning statistics and refreshed as new data lands. The Royal Borough grants a fair share of householder applications but under exacting design control, with borough-wide conservation status and its restrictive basement policy the defining constraints. Prior approval turns on neighbour amenity alone, so the drawings that matter are the ones showing the relationship to the boundary.
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 Chelsea, Kensington and Notting Hill, the notifications that clear without objection are the ones that treat the neighbour as the audience. We show the extension in section against the boundary, demonstrate the 45-degree daylight relationship to the nearest habitable window, and where the plot is tight we taper the depth away from the boundary rather than running the full 6 metres to the fence.
With the roofscape closely protected, mansard and roof additions are judged against the prevailing profile of each terrace group. Where an objection does arrive, the council's assessment is narrow: loss of light, outlook and overbearing effect on the adjoining property, nothing else. A pack that has already answered those three points on the drawings usually survives an objection, whereas one that leaves them to the officer's imagination usually does not.
We prepare prior-approval notifications across Kensington and Chelsea. A few of the areas where deep rear extensions come up most often:
Prior approval drawings for Chelsea — stucco terraces and mews streets off the King's Road — dimensioned to the 6m and 8m limits and prepared for the Royal Borough of Kensington and Chelsea's neighbour consultation.
Prior approval drawings for Kensington — grand stucco terraces and mansion blocks — dimensioned to the 6m and 8m limits and prepared for the Royal Borough of Kensington and Chelsea's neighbour consultation.
Prior approval drawings for Notting Hill — the Ladbroke Estate's stucco terraces around communal garden squares — dimensioned to the 6m and 8m limits and prepared for the Royal Borough of Kensington and Chelsea's neighbour consultation.
Prior approval drawings for Holland Park — large detached villas and substantial mansion flats — dimensioned to the 6m and 8m limits and prepared for the Royal Borough of Kensington and Chelsea's neighbour consultation.
Prior approval drawings for Knightsbridge — red-brick mansion blocks and stucco terraces — dimensioned to the 6m and 8m limits and prepared for the Royal Borough of Kensington and Chelsea's neighbour consultation.
Prior approval drawings for Earls Court — tall Victorian terraces widely subdivided into flats — dimensioned to the 6m and 8m limits and prepared for the Royal Borough of Kensington and Chelsea's neighbour consultation.
Same extension, two routes, very different tests.
| Route | Depth allowed | What the council may consider | Timescale |
|---|---|---|---|
| Ordinary Class A permitted development | 3m attached / 4m detached | Nothing — no application needed | Immediate |
| Larger home extension prior approval | 6m attached / 8m detached | Amenity of adjoining premises, only if a neighbour objects | 21-day consultation, 42-day determination |
| Full householder application | No fixed limit | Design, materials, policy, amenity, everything | 8-week target |
| Any of these on designated land | 3m / 4m only | Prior approval scheme unavailable | Full application beyond the limits |
Limits and procedure from the GPDO 2015, Schedule 2, Part 1, Class A and paragraph A.4, made permanent by amendment in 2019.
A process built around the 21-day consultation, which is where these schemes are won or lost.
Send us your Kensington and Chelsea postcode and house type. We confirm whether the property is on designated land, whether the scheme is available, and what depth you can realistically take.
We measure the original rear wall, eaves height, boundary distances and the neighbouring windows that the amenity assessment will turn on.
We draw the extension to the 6m or 8m limit with the boundary relationship shown in section, and prepare the written description and adjoining-owner details the Royal Borough of Kensington and Chelsea needs to start the consultation.
We submit, track the 21-day consultation and the 42-day determination, respond to any objection on amenity grounds, and revise free until the decision.
Three metres on a terraced or semi-detached house and four on a detached one under ordinary permitted development. Under the larger home extension prior approval scheme those double to six and eight metres, provided you notify the Royal Borough of Kensington and Chelsea before starting and the conditions on height, materials and land coverage are met. The scheme is not available on designated land.
It is a notification, not an application for permission. You tell the Royal Borough of Kensington and Chelsea what you intend to build, it writes to the adjoining owners, and they have 21 days to object. If nobody objects, you may build. If someone does, the council assesses the effect on the amenity of adjoining premises and must decide within 42 days. Design and policy are not in scope.
The council then considers the impact on the amenity of the adjoining property — loss of light, loss of outlook, and overbearing effect — and nothing else. It cannot refuse because it dislikes the design or the materials. We prepare the drawings so those three questions are already answered in section and on the site plan, which is what usually carries an objected scheme through. This applies to your Kensington and Chelsea address specifically. the Royal Borough of Kensington and Chelsea is the decision-maker.
No. The larger home extension scheme is unavailable on designated land, which includes conservation areas such as Chelsea and Kensington, national landscapes, national parks and world heritage sites. On those properties the ordinary 3-metre and 4-metre limits apply, and anything deeper needs a full householder application to the Royal Borough of Kensington and Chelsea.
Twenty-one days for the neighbour consultation, and a maximum of 42 days from a valid submission for the council to determine it. If the council does not respond within 42 days you may proceed as notified. That deadline is the scheme's real advantage over a full application, and it is why validation completeness matters so much. This applies to your Kensington and Chelsea address specifically. the Royal Borough of Kensington and Chelsea is the decision-maker.
Yes — always. Prior approval deals only with the planning position. A 6-metre rear extension still needs building control approval for foundations, structure, drainage, thermal performance and fire safety, and the beam over the opening into the existing house needs designing and calculating. We prepare both sets so the notified scheme is the buildable one. This applies to your Kensington and Chelsea address specifically. the Royal Borough of Kensington and Chelsea is the decision-maker.
We quote each Kensington and Chelsea scheme individually, because plot shape and the boundary relationship drive the work, and send a fixed, no-obligation quote within one working day. It covers the notification pack and free revisions until the Royal Borough of Kensington and Chelsea determines it. Call 020 7864 7245 to start.
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Same fixed quotes, same fast drawings — wherever your project is.