Kensington and Chelsea, London
Double-storey extension drawings in Kensington and Chelsea
Double-storey extension drawings for a Kensington and Chelsea home start at £1,295 including VAT. The extensions policy in the Local Plan 2024 (New Local Plan Review) asks extensions to stay subordinate to the original building, and the borough resists any addition that disturbs the even rhythm of a terrace's rear elevations.
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Kensington and Chelsea's policy on double-storey extensions
The extensions policy in the Local Plan sets the test for an upper-floor addition here. It says extensions must be subordinate to the original building and are resisted where they disrupt the even rhythm of rear additions or impair the symmetry of a terrace. There is no depth figure to design to, which makes judgement, not arithmetic, the test.
In practice, that means a double-storey addition is read against its neighbours. On a terrace where every back addition steps down at the same height, a new upper floor that rises above the line is the exact thing the policy names. Where the terrace has already been broken by earlier extensions, the case is different, and we gather those approvals as evidence.
We therefore start with an elevation of the whole terrace rear, drawn from survey and the council's register, and test the proposal against it. That drawing does more for an application here than any dimension.
Local figures for Kensington and Chelsea
| Measure | Value | Period | Source |
|---|---|---|---|
| Conservation areas | 39 named conservation areas published by the council | — | planning.data.gov.uk |
| Article 4 directions | 84 Article 4 directions published by the council | — | planning.data.gov.uk |
| Listed building entries | 1,350 list entries (Historic England, within the LPA boundary) | — | planning.data.gov.uk |
| Tree preservation orders | 4,560 tree preservation orders published by the council | — | planning.data.gov.uk |
| Supplementary planning document | Basements SPD | 2016 | rbkc.gov.uk |
| Householder decisions | 664 decisions | 1 July 2025 - 30 June 2026 | assets.publishing.service.gov.uk |
| Householder applications granted | 93.7 % | 1 July 2025 - 30 June 2026 | assets.publishing.service.gov.uk |
| Householder applications decided in time | 91.9 % decided within 8 weeks or an agreed extended period | 1 July 2025 - 30 June 2026 | assets.publishing.service.gov.uk |
| Class A, para A.1(h) | Over one storey: max 3 m beyond the original rear wall and not within 7 m of the rear boundary | — | legislation.gov.uk |
| Class A, para A.2(c) | No rear extension of more than one storey under PD on article 2(3) land | — | legislation.gov.uk |
| Approved Document B Vol 1, 2019 ed. incl. 2026 amendments, para 2.10 | Escape window: unobstructed openable area at least 0.33 m², at least 450 mm high and 450 mm wide, bottom of opening no more than 1100 mm above floor | — | gov.uk |
| Party Wall etc. Act 1996 s3(2)(a) | Party structure notice at least 2 months before work | — | legislation.gov.uk |
A blank value means the figure has not been published, not that there are none. Check your own address with the council.
The 45-degree test in plan
A line from the middle of the neighbour's nearest window: the extension should stay behind it.
- A · Test used in daylight assessments
- 45 degrees (plan and elevation)
Basements, trees and what sits below the extension
Where a scheme combines an upper floor with a basement, the council's Basements SPD also applies. The borough also has 4,560 tree preservation orders in force, so a mature garden tree near the footprint can shape the foundation design as much as the neighbours' windows.
We show both on the site plan and flag them before the structural engineer is briefed, which avoids a redesign once a root protection area is mapped.
A borough of heritage constraints
Kensington and Chelsea has 39 conservation areas, 84 Article 4 directions and 1,350 listed building entries. In a conservation area: No rear extension of more than one storey under PD on article 2(3) land.
Owners of listed houses need listed building consent for most work. Our architectural drawings in Kensington and Chelsea page explains how we run those checks.
Permitted development and the upper floor
Where an address is outside the protected land, the national rule is: Over one storey: max 3 m beyond the original rear wall and not within 7 m of the rear boundary. A long plot can meet it, but an Article 4 direction can remove the right, so we check the address before relying on it.
Even then the conditions remain. Side windows: Upper-floor side windows obscure-glazed and non-opening below 1.7 m above floor. Roof: Roof pitch of a 2+ storey enlargement to match the original house so far as practicable.
Fire escape and party structure
A first-floor bedroom needs an escape window: Escape window: unobstructed openable area at least 0.33 m², at least 450 mm high and 450 mm wide, bottom of opening no more than 1100 mm above floor. Terrace owners should also plan the notices: Party structure notice at least 2 months before work. Where excavation is involved: Adjacent excavation notice at least 1 month before work: within 3 m and deeper than the neighbour's foundations, or within 6 m and cutting a 45° line from their foundations.
Householder decisions in the borough
The borough decided 664 householder applications in its latest published year and granted 93.7 per cent, deciding 91.9 per cent on time. These numbers cover every kind of householder scheme and carry no promise about one house.
Your drawing set, the price and nearby services
The set covers both floors, the roof section and every elevation, plus the rear terrace elevation described above. It starts at £1,295 with VAT included, fixed before you commit. A second chartered technologist checks every sheet, and we redraw free until approval where changes are requested.
Weighing a wider scheme? See house extension drawings in Kensington and Chelsea, or rear extension drawings in Kensington and Chelsea for a ground-floor option. Next door, Westminster and Hammersmith and Fulham each have their own rules.
What you receive
Related pages
Other services in Kensington and Chelsea
Questions
Is there a maximum depth for a rear extension in Kensington and Chelsea?
The extensions policy gives no depth figure. It asks extensions to be subordinate to the original building and resists those that disrupt the even rhythm of rear additions or the symmetry of a terrace.
How many conservation areas are there in Kensington and Chelsea?
39, with 84 Article 4 directions and 1,350 listed building entries.
Can a double-storey extension be permitted development in Kensington and Chelsea?
Only outside protected land and within the national limits. The rule is: Over one storey: max 3 m beyond the original rear wall and not within 7 m of the rear boundary. An Article 4 direction can remove it.
How much do double-storey extension drawings cost in Kensington and Chelsea?
From £1,295 including VAT, fixed up front. The council's application fee is separate.
Sources and dates
- planning.data.gov.uk, retrieved
- planning.data.gov.uk, retrieved
- planning.data.gov.uk, retrieved
- planning.data.gov.uk, retrieved
- rbkc.gov.uk, retrieved
- assets.publishing.service.gov.uk, retrieved
- legislation.gov.uk, retrieved
- gov.uk, retrieved
- legislation.gov.uk, retrieved
- rbkc.gov.uk, retrieved
- merton.gov.uk, retrieved
- Contains public sector information licensed under the Open Government Licence v3.0.
- Contains OS data © Crown copyright and database right 2026.
- Contains HM Land Registry data © Crown copyright and database right 2026. This data is licensed under the Open Government Licence v3.0.
- Contains Historic England data © Historic England 2026. Contains Ordnance Survey data © Crown copyright and database right 2026.
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